commit fea18c6863 upstream.
vmap_pages_pte_range() enters the lazy MMU mode, but fails to leave it in
case an error is encountered.
Link: https://lkml.kernel.org/r/20250623075721.2817094-1-agordeev@linux.ibm.com
Fixes: 2ba3e6947a ("mm/vmalloc: track which page-table levels were modified")
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/r/202506132017.T1l1l6ME-lkp@intel.com/
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 0ea148a799 upstream.
This commit fixes two kinds of races, they may have different results:
Barry reported a BUG_ON in commit c50f8e6053, we may see the same
BUG_ON if the filemap lookup returned NULL and folio is added to swap
cache after that.
If another kind of race is triggered (folio changed after lookup) we
may see RSS counter is corrupted:
[ 406.893936] BUG: Bad rss-counter state mm:ffff0000c5a9ddc0
type:MM_ANONPAGES val:-1
[ 406.894071] BUG: Bad rss-counter state mm:ffff0000c5a9ddc0
type:MM_SHMEMPAGES val:1
Because the folio is being accounted to the wrong VMA.
I'm not sure if there will be any data corruption though, seems no.
The issues above are critical already.
On seeing a swap entry PTE, userfaultfd_move does a lockless swap cache
lookup, and tries to move the found folio to the faulting vma. Currently,
it relies on checking the PTE value to ensure that the moved folio still
belongs to the src swap entry and that no new folio has been added to the
swap cache, which turns out to be unreliable.
While working and reviewing the swap table series with Barry, following
existing races are observed and reproduced [1]:
In the example below, move_pages_pte is moving src_pte to dst_pte, where
src_pte is a swap entry PTE holding swap entry S1, and S1 is not in the
swap cache:
CPU1 CPU2
userfaultfd_move
move_pages_pte()
entry = pte_to_swp_entry(orig_src_pte);
// Here it got entry = S1
... < interrupted> ...
<swapin src_pte, alloc and use folio A>
// folio A is a new allocated folio
// and get installed into src_pte
<frees swap entry S1>
// src_pte now points to folio A, S1
// has swap count == 0, it can be freed
// by folio_swap_swap or swap
// allocator's reclaim.
<try to swap out another folio B>
// folio B is a folio in another VMA.
<put folio B to swap cache using S1 >
// S1 is freed, folio B can use it
// for swap out with no problem.
...
folio = filemap_get_folio(S1)
// Got folio B here !!!
... < interrupted again> ...
<swapin folio B and free S1>
// Now S1 is free to be used again.
<swapout src_pte & folio A using S1>
// Now src_pte is a swap entry PTE
// holding S1 again.
folio_trylock(folio)
move_swap_pte
double_pt_lock
is_pte_pages_stable
// Check passed because src_pte == S1
folio_move_anon_rmap(...)
// Moved invalid folio B here !!!
The race window is very short and requires multiple collisions of multiple
rare events, so it's very unlikely to happen, but with a deliberately
constructed reproducer and increased time window, it can be reproduced
easily.
This can be fixed by checking if the folio returned by filemap is the
valid swap cache folio after acquiring the folio lock.
Another similar race is possible: filemap_get_folio may return NULL, but
folio (A) could be swapped in and then swapped out again using the same
swap entry after the lookup. In such a case, folio (A) may remain in the
swap cache, so it must be moved too:
CPU1 CPU2
userfaultfd_move
move_pages_pte()
entry = pte_to_swp_entry(orig_src_pte);
// Here it got entry = S1, and S1 is not in swap cache
folio = filemap_get_folio(S1)
// Got NULL
... < interrupted again> ...
<swapin folio A and free S1>
<swapout folio A re-using S1>
move_swap_pte
double_pt_lock
is_pte_pages_stable
// Check passed because src_pte == S1
folio_move_anon_rmap(...)
// folio A is ignored !!!
Fix this by checking the swap cache again after acquiring the src_pte
lock. And to avoid the filemap overhead, we check swap_map directly [2].
The SWP_SYNCHRONOUS_IO path does make the problem more complex, but so far
we don't need to worry about that, since folios can only be exposed to the
swap cache in the swap out path, and this is covered in this patch by
checking the swap cache again after acquiring the src_pte lock.
Testing with a simple C program that allocates and moves several GB of
memory did not show any observable performance change.
Link: https://lkml.kernel.org/r/20250604151038.21968-1-ryncsn@gmail.com
Fixes: adef440691 ("userfaultfd: UFFDIO_MOVE uABI")
Signed-off-by: Kairui Song <kasong@tencent.com>
Closes: https://lore.kernel.org/linux-mm/CAMgjq7B1K=6OOrK2OUZ0-tqCzi+EJt+2_K97TPGoSt=9+JwP7Q@mail.gmail.com/ [1]
Link: https://lore.kernel.org/all/CAGsJ_4yJhJBo16XhiC-nUzSheyX-V3-nFE+tAi=8Y560K8eT=A@mail.gmail.com/ [2]
Reviewed-by: Lokesh Gidra <lokeshgidra@google.com>
Acked-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Barry Song <baohua@kernel.org>
Reviewed-by: Chris Li <chrisl@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
(cherry picked from commit 0ea148a799)
[ lokeshgidra: resolved merged conflict caused by the difference in
move_swap_pte() arguments ]
Signed-off-by: Lokesh Gidra <lokeshgidra@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 5c5f0468d1 upstream.
The following data-race was found in show_numa_info():
==================================================================
BUG: KCSAN: data-race in vmalloc_info_show / vmalloc_info_show
read to 0xffff88800971fe30 of 4 bytes by task 8289 on cpu 0:
show_numa_info mm/vmalloc.c:4936 [inline]
vmalloc_info_show+0x5a8/0x7e0 mm/vmalloc.c:5016
seq_read_iter+0x373/0xb40 fs/seq_file.c:230
proc_reg_read_iter+0x11e/0x170 fs/proc/inode.c:299
....
write to 0xffff88800971fe30 of 4 bytes by task 8287 on cpu 1:
show_numa_info mm/vmalloc.c:4934 [inline]
vmalloc_info_show+0x38f/0x7e0 mm/vmalloc.c:5016
seq_read_iter+0x373/0xb40 fs/seq_file.c:230
proc_reg_read_iter+0x11e/0x170 fs/proc/inode.c:299
....
value changed: 0x0000008f -> 0x00000000
==================================================================
According to this report,there is a read/write data-race because
m->private is accessible to multiple CPUs. To fix this, instead of
allocating the heap in proc_vmalloc_init() and passing the heap address to
m->private, vmalloc_info_show() should allocate the heap.
Link: https://lkml.kernel.org/r/20250508165620.15321-1-aha310510@gmail.com
Fixes: 8e1d743f2c ("mm: vmalloc: support multiple nodes in vmallocinfo")
Signed-off-by: Jeongjun Park <aha310510@gmail.com>
Suggested-by: Eric Dumazet <edumazet@google.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit cbe4134ea4 ]
Export anon_inode_make_secure_inode() to allow KVM guest_memfd to create
anonymous inodes with proper security context. This replaces the current
pattern of calling alloc_anon_inode() followed by
inode_init_security_anon() for creating security context manually.
This change also fixes a security regression in secretmem where the
S_PRIVATE flag was not cleared after alloc_anon_inode(), causing
LSM/SELinux checks to be bypassed for secretmem file descriptors.
As guest_memfd currently resides in the KVM module, we need to export this
symbol for use outside the core kernel. In the future, guest_memfd might be
moved to core-mm, at which point the symbols no longer would have to be
exported. When/if that happens is still unclear.
Fixes: 2bfe15c526 ("mm: create security context for memfd_secret inodes")
Suggested-by: David Hildenbrand <david@redhat.com>
Suggested-by: Mike Rapoport <rppt@kernel.org>
Signed-off-by: Shivank Garg <shivankg@amd.com>
Link: https://lore.kernel.org/20250620070328.803704-3-shivankg@amd.com
Acked-by: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit c1feab95e0 ]
Quite a few places want to build a struct qstr by given string;
it would be convenient to have a primitive doing that, rather
than open-coding it via QSTR_INIT().
The closest approximation was in bcachefs, but that expands to
initializer list - {.len = strlen(string), .name = string}.
It would be more useful to have it as compound literal -
(struct qstr){.len = strlen(string), .name = string}.
Unlike initializer list it's a valid expression. What's more,
it's a valid lvalue - it's an equivalent of anonymous local
variable with such initializer, so the things like
path->dentry = d_alloc_pseudo(mnt->mnt_sb, &QSTR(name));
are valid. It can also be used as initializer, with identical
effect -
struct qstr x = (struct qstr){.name = s, .len = strlen(s)};
is equivalent to
struct qstr anon_variable = {.name = s, .len = strlen(s)};
struct qstr x = anon_variable;
// anon_variable is never used after that point
and any even remotely sane compiler will manage to collapse that
into
struct qstr x = {.name = s, .len = strlen(s)};
What compound literals can't be used for is initialization of
global variables, but those are covered by QSTR_INIT().
This commit lifts definition(s) of QSTR() into linux/dcache.h,
converts it to compound literal (all bcachefs users are fine
with that) and converts assorted open-coded instances to using
that.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Stable-dep-of: cbe4134ea4 ("fs: export anon_inode_make_secure_inode() and fix secretmem LSM bypass")
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 0cf4b1687a upstream.
While an OOM failure in commit_merge() isn't really feasible due to the
allocation which might fail (a maple tree pre-allocation) being 'too small
to fail', we do need to handle this case correctly regardless.
In vma_merge_existing_range(), we can theoretically encounter failures
which result in an OOM error in two ways - firstly dup_anon_vma() might
fail with an OOM error, and secondly commit_merge() failing, ultimately,
to pre-allocate a maple tree node.
The abort logic for dup_anon_vma() resets the VMA iterator to the initial
range, ensuring that any logic looping on this iterator will correctly
proceed to the next VMA.
However the commit_merge() abort logic does not do the same thing. This
resulted in a syzbot report occurring because mlockall() iterates through
VMAs, is tolerant of errors, but ended up with an incorrect previous VMA
being specified due to incorrect iterator state.
While making this change, it became apparent we are duplicating logic -
the logic introduced in commit 41e6ddcaa0 ("mm/vma: add give_up_on_oom
option on modify/merge, use in uffd release") duplicates the
vmg->give_up_on_oom check in both abort branches.
Additionally, we observe that we can perform the anon_dup check safely on
dup_anon_vma() failure, as this will not be modified should this call
fail.
Finally, we need to reset the iterator in both cases, so now we can simply
use the exact same code to abort for both.
We remove the VM_WARN_ON(err != -ENOMEM) as it would be silly for this to
be otherwise and it allows us to implement the abort check more neatly.
Link: https://lkml.kernel.org/r/20250606125032.164249-1-lorenzo.stoakes@oracle.com
Fixes: 47b16d0462 ("mm: abort vma_modify() on merge out of memory failure")
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reported-by: syzbot+d16409ea9ecc16ed261a@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-mm/6842cc67.a00a0220.29ac89.003b.GAE@google.com/
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Jann Horn <jannh@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 517f496e1e upstream.
After commit 1aaf8c1229 ("mm: gup: fix infinite loop within
__get_longterm_locked") we are able to longterm pin folios that are not
supposed to get longterm pinned, simply because they temporarily have the
LRU flag cleared (esp. temporarily isolated).
For example, two __get_longterm_locked() callers can race, or
__get_longterm_locked() can race with anything else that temporarily
isolates folios.
The introducing commit mentions the use case of a driver that uses
vm_ops->fault to insert pages allocated through cma_alloc() into the page
tables, assuming they can later get longterm pinned. These pages/ folios
would never have the LRU flag set and consequently cannot get isolated.
There is no known in-tree user making use of that so far, fortunately.
To handle that in the future -- and avoid retrying forever to
isolate/migrate them -- we will need a different mechanism for the CMA
area *owner* to indicate that it actually already allocated the page and
is fine with longterm pinning it. The LRU flag is not suitable for that.
Probably we can lookup the relevant CMA area and query the bitmap; we only
have have to care about some races, probably. If already allocated, we
could just allow longterm pinning)
Anyhow, let's fix the "must not be longterm pinned" problem first by
reverting the original commit.
Link: https://lkml.kernel.org/r/20250611131314.594529-1-david@redhat.com
Fixes: 1aaf8c1229 ("mm: gup: fix infinite loop within __get_longterm_locked")
Signed-off-by: David Hildenbrand <david@redhat.com>
Closes: https://lore.kernel.org/all/20250522092755.GA3277597@tiffany/
Reported-by: Hyesoo Yu <hyesoo.yu@samsung.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Peter Xu <peterx@redhat.com>
Cc: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
Cc: Aijun Sun <aijun.sun@unisoc.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 4f489fe6af upstream.
memcg_path_store() assigns a newly allocated memory buffer to
filter->memcg_path, without deallocating the previously allocated and
assigned memory buffer. As a result, users can leak kernel memory by
continuously writing a data to memcg_path DAMOS sysfs file. Fix the leak
by deallocating the previously set memory buffer.
Link: https://lkml.kernel.org/r/20250619183608.6647-2-sj@kernel.org
Fixes: 7ee161f18b ("mm/damon/sysfs-schemes: implement filter directory")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: <stable@vger.kernel.org> [6.3.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 081056dc00 upstream.
Currently, __split_vma() triggers hugetlb page table unsharing through
vm_ops->may_split(). This happens before the VMA lock and rmap locks are
taken - which is too early, it allows racing VMA-locked page faults in our
process and racing rmap walks from other processes to cause page tables to
be shared again before we actually perform the split.
Fix it by explicitly calling into the hugetlb unshare logic from
__split_vma() in the same place where THP splitting also happens. At that
point, both the VMA and the rmap(s) are write-locked.
An annoying detail is that we can now call into the helper
hugetlb_unshare_pmds() from two different locking contexts:
1. from hugetlb_split(), holding:
- mmap lock (exclusively)
- VMA lock
- file rmap lock (exclusively)
2. hugetlb_unshare_all_pmds(), which I think is designed to be able to
call us with only the mmap lock held (in shared mode), but currently
only runs while holding mmap lock (exclusively) and VMA lock
Backporting note:
This commit fixes a racy protection that was introduced in commit
b30c14cd61 ("hugetlb: unshare some PMDs when splitting VMAs"); that
commit claimed to fix an issue introduced in 5.13, but it should actually
also go all the way back.
[jannh@google.com: v2]
Link: https://lkml.kernel.org/r/20250528-hugetlb-fixes-splitrace-v2-1-1329349bad1a@google.com
Link: https://lkml.kernel.org/r/20250528-hugetlb-fixes-splitrace-v2-0-1329349bad1a@google.com
Link: https://lkml.kernel.org/r/20250527-hugetlb-fixes-splitrace-v1-1-f4136f5ec58a@google.com
Fixes: 39dde65c99 ("[PATCH] shared page table for hugetlb page")
Signed-off-by: Jann Horn <jannh@google.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org> [b30c14cd6102: hugetlb: unshare some PMDs when splitting VMAs]
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
[stable backport: added missing include]
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 383c4613c6 upstream.
Commit 3ea277194d ("mm, mprotect: flush TLB if potentially racing with a
parallel reclaim leaving stale TLB entries") described a theoretical race
as such:
"""
Nadav Amit identified a theoretical race between page reclaim and mprotect
due to TLB flushes being batched outside of the PTL being held.
He described the race as follows:
CPU0 CPU1
---- ----
user accesses memory using RW PTE
[PTE now cached in TLB]
try_to_unmap_one()
==> ptep_get_and_clear()
==> set_tlb_ubc_flush_pending()
mprotect(addr, PROT_READ)
==> change_pte_range()
==> [ PTE non-present - no flush ]
user writes using cached RW PTE
...
try_to_unmap_flush()
The same type of race exists for reads when protecting for PROT_NONE and
also exists for operations that can leave an old TLB entry behind such as
munmap, mremap and madvise.
"""
The solution was to introduce flush_tlb_batched_pending() and call it
under the PTL from mprotect/madvise/munmap/mremap to complete any pending
tlb flushes.
However, while madvise_free_pte_range() and
madvise_cold_or_pageout_pte_range() were both retro-fitted to call
flush_tlb_batched_pending() immediately after initially acquiring the PTL,
they both temporarily release the PTL to split a large folio if they
stumble upon one. In this case, where re-acquiring the PTL
flush_tlb_batched_pending() must be called again, but it previously was
not. Let's fix that.
There are 2 Fixes: tags here: the first is the commit that fixed
madvise_free_pte_range(). The second is the commit that added
madvise_cold_or_pageout_pte_range(), which looks like it copy/pasted the
faulty pattern from madvise_free_pte_range().
This is a theoretical bug discovered during code review.
Link: https://lkml.kernel.org/r/20250606092809.4194056-1-ryan.roberts@arm.com
Fixes: 3ea277194d ("mm, mprotect: flush TLB if potentially racing with a parallel reclaim leaving stale TLB entries")
Fixes: 9c276cc65a ("mm: introduce MADV_COLD")
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Jann Horn <jannh@google.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mel Gorman <mgorman <mgorman@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 1013af4f58 upstream.
huge_pmd_unshare() drops a reference on a page table that may have
previously been shared across processes, potentially turning it into a
normal page table used in another process in which unrelated VMAs can
afterwards be installed.
If this happens in the middle of a concurrent gup_fast(), gup_fast() could
end up walking the page tables of another process. While I don't see any
way in which that immediately leads to kernel memory corruption, it is
really weird and unexpected.
Fix it with an explicit broadcast IPI through tlb_remove_table_sync_one(),
just like we do in khugepaged when removing page tables for a THP
collapse.
Link: https://lkml.kernel.org/r/20250528-hugetlb-fixes-splitrace-v2-2-1329349bad1a@google.com
Link: https://lkml.kernel.org/r/20250527-hugetlb-fixes-splitrace-v1-2-f4136f5ec58a@google.com
Fixes: 39dde65c99 ("[PATCH] shared page table for hugetlb page")
Signed-off-by: Jann Horn <jannh@google.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f83f362d40 upstream.
In dirty_ratio_handler(), vm_dirty_bytes must be set to zero before
calling writeback_set_ratelimit(), as global_dirty_limits() always
prioritizes the value of vm_dirty_bytes.
It's domain_dirty_limits() that's relevant here, not node_dirty_ok:
dirty_ratio_handler
writeback_set_ratelimit
global_dirty_limits(&dirty_thresh) <- ratelimit_pages based on dirty_thresh
domain_dirty_limits
if (bytes) <- bytes = vm_dirty_bytes <--------+
thresh = f1(bytes) <- prioritizes vm_dirty_bytes |
else |
thresh = f2(ratio) |
ratelimit_pages = f3(dirty_thresh) |
vm_dirty_bytes = 0 <- it's late! ---------------------+
This causes ratelimit_pages to still use the value calculated based on
vm_dirty_bytes, which is wrong now.
The impact visible to userspace is difficult to capture directly because
there is no procfs/sysfs interface exported to user space. However, it
will have a real impact on the balance of dirty pages.
For example:
1. On default, we have vm_dirty_ratio=40, vm_dirty_bytes=0
2. echo 8192 > dirty_bytes, then vm_dirty_bytes=8192,
vm_dirty_ratio=0, and ratelimit_pages is calculated based on
vm_dirty_bytes now.
3. echo 20 > dirty_ratio, then since vm_dirty_bytes is not reset to
zero when writeback_set_ratelimit() -> global_dirty_limits() ->
domain_dirty_limits() is called, reallimit_pages is still calculated
based on vm_dirty_bytes instead of vm_dirty_ratio. This does not
conform to the actual intent of the user.
Link: https://lkml.kernel.org/r/20250415090232.7544-1-alexjlzheng@tencent.com
Fixes: 9d823e8f6b ("writeback: per task dirty rate limit")
Signed-off-by: Jinliang Zheng <alexjlzheng@tencent.com>
Reviewed-by: MengEn Sun <mengensun@tencent.com>
Cc: Andrea Righi <andrea@betterlinux.com>
Cc: Fenggaung Wu <fengguang.wu@intel.com>
Cc: Jinliang Zheng <alexjlzheng@tencent.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit cd3c93167d ]
Since we are about to stash some more information into the pp_magic
field, let's move the magic signature checks into a pair of helper
functions so it can be changed in one place.
Reviewed-by: Mina Almasry <almasrymina@google.com>
Tested-by: Yonglong Liu <liuyonglong@huawei.com>
Acked-by: Jesper Dangaard Brouer <hawk@kernel.org>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://patch.msgid.link/20250409-page-pool-track-dma-v9-1-6a9ef2e0cba8@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 70d1eb031a upstream.
The common case is to grow reallocations, and since init_on_alloc will
have already zeroed the whole allocation, we only need to zero when
shrinking the allocation.
Link: https://lkml.kernel.org/r/20250515214217.619685-2-kees@kernel.org
Fixes: a0309faf1c ("mm: vmalloc: support more granular vrealloc() sizing")
Signed-off-by: Kees Cook <kees@kernel.org>
Tested-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Eduard Zingerman <eddyz87@gmail.com>
Cc: "Erhard F." <erhard_f@mailbox.org>
Cc: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f7a35a3c36 upstream.
Patch series "mm: vmalloc: Actually use the in-place vrealloc region".
This fixes a performance regression[1] with vrealloc()[1].
The refactoring to not build a new vmalloc region only actually worked
when shrinking. Actually return the resized area when it grows. Ugh.
Link: https://lkml.kernel.org/r/20250515214217.619685-1-kees@kernel.org
Fixes: a0309faf1c ("mm: vmalloc: support more granular vrealloc() sizing")
Signed-off-by: Kees Cook <kees@kernel.org>
Reported-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Closes: https://lore.kernel.org/all/20250515-bpf-verifier-slowdown-vwo2meju4cgp2su5ckj@6gi6ssxbnfqg [1]
Tested-by: Eduard Zingerman <eddyz87@gmail.com>
Tested-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Tested-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Reviewed-by: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Cc: "Erhard F." <erhard_f@mailbox.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e05741fb10 upstream.
__alloc_pages_slowpath has no change detection for ac->nodemask in the
part of retry path, while cpuset can modify it in parallel. For some
processes that set mempolicy as MPOL_BIND, this results ac->nodemask
changes, and then the should_reclaim_retry will judge based on the latest
nodemask and jump to retry, while the get_page_from_freelist only
traverses the zonelist from ac->preferred_zoneref, which selected by a
expired nodemask and may cause infinite retries in some cases
cpu 64:
__alloc_pages_slowpath {
/* ..... */
retry:
/* ac->nodemask = 0x1, ac->preferred->zone->nid = 1 */
if (alloc_flags & ALLOC_KSWAPD)
wake_all_kswapds(order, gfp_mask, ac);
/* cpu 1:
cpuset_write_resmask
update_nodemask
update_nodemasks_hier
update_tasks_nodemask
mpol_rebind_task
mpol_rebind_policy
mpol_rebind_nodemask
// mempolicy->nodes has been modified,
// which ac->nodemask point to
*/
/* ac->nodemask = 0x3, ac->preferred->zone->nid = 1 */
if (should_reclaim_retry(gfp_mask, order, ac, alloc_flags,
did_some_progress > 0, &no_progress_loops))
goto retry;
}
Simultaneously starting multiple cpuset01 from LTP can quickly reproduce
this issue on a multi node server when the maximum memory pressure is
reached and the swap is enabled
Link: https://lkml.kernel.org/r/20250416082405.20988-1-zhangtianyang@loongson.cn
Fixes: c33d6c06f6 ("mm, page_alloc: avoid looking up the first zone in a zonelist twice")
Signed-off-by: Tianyang Zhang <zhangtianyang@loongson.cn>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 06717a7b6c upstream.
I am seeing soft lockup on certain machine types when a cgroup OOMs. This
is happening because killing the process in certain machine might be very
slow, which causes the soft lockup and RCU stalls. This happens usually
when the cgroup has MANY processes and memory.oom.group is set.
Example I am seeing in real production:
[462012.244552] Memory cgroup out of memory: Killed process 3370438 (crosvm) ....
....
[462037.318059] Memory cgroup out of memory: Killed process 4171372 (adb) ....
[462037.348314] watchdog: BUG: soft lockup - CPU#64 stuck for 26s! [stat_manager-ag:1618982]
....
Quick look at why this is so slow, it seems to be related to serial flush
for certain machine types. For all the crashes I saw, the target CPU was
at console_flush_all().
In the case above, there are thousands of processes in the cgroup, and it
is soft locking up before it reaches the 1024 limit in the code (which
would call the cond_resched()). So, cond_resched() in 1024 blocks is not
sufficient.
Remove the counter-based conditional rescheduling logic and call
cond_resched() unconditionally after each task iteration, after fn() is
called. This avoids the lockup independently of how slow fn() is.
Link: https://lkml.kernel.org/r/20250523-memcg_fix-v1-1-ad3eafb60477@debian.org
Fixes: ade81479c7 ("memcg: fix soft lockup in the OOM process")
Signed-off-by: Breno Leitao <leitao@debian.org>
Suggested-by: Rik van Riel <riel@surriel.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Michael van der Westhuizen <rmikey@meta.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Pavel Begunkov <asml.silence@gmail.com>
Cc: Chen Ridong <chenridong@huawei.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit fefc075182 upstream.
The page allocator tracks the number of zones that have unaccepted memory
using static_branch_enc/dec() and uses that static branch in hot paths to
determine if it needs to deal with unaccepted memory.
Borislav and Thomas pointed out that the tracking is racy: operations on
static_branch are not serialized against adding/removing unaccepted pages
to/from the zone.
Sanity checks inside static_branch machinery detects it:
WARNING: CPU: 0 PID: 10 at kernel/jump_label.c:276 __static_key_slow_dec_cpuslocked+0x8e/0xa0
The comment around the WARN() explains the problem:
/*
* Warn about the '-1' case though; since that means a
* decrement is concurrent with a first (0->1) increment. IOW
* people are trying to disable something that wasn't yet fully
* enabled. This suggests an ordering problem on the user side.
*/
The effect of this static_branch optimization is only visible on
microbenchmark.
Instead of adding more complexity around it, remove it altogether.
Link: https://lkml.kernel.org/r/20250506133207.1009676-1-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Fixes: dcdfdd40fa ("mm: Add support for unaccepted memory")
Link: https://lore.kernel.org/all/20250506092445.GBaBnVXXyvnazly6iF@fat_crate.local
Reported-by: Borislav Petkov <bp@alien8.de>
Tested-by: Borislav Petkov (AMD) <bp@alien8.de>
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: <stable@vger.kernel.org> [6.5+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 75cb1cca2c upstream.
As David pointed out, what truly matters for mremap and userfaultfd move
operations is the soft dirty bit. The current comment and
implementation—which always sets the dirty bit for present PTEs and
fails to set the soft dirty bit for swap PTEs—are incorrect. This could
break features like Checkpoint-Restore in Userspace (CRIU).
This patch updates the behavior to correctly set the soft dirty bit for
both present and swap PTEs in accordance with mremap.
Link: https://lkml.kernel.org/r/20250508220912.7275-1-21cnbao@gmail.com
Fixes: adef440691 ("userfaultfd: UFFDIO_MOVE uABI")
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Reported-by: David Hildenbrand <david@redhat.com>
Closes: https://lore.kernel.org/linux-mm/02f14ee1-923f-47e3-a994-4950afb9afcc@redhat.com/
Acked-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 90abee6d78 upstream.
The test robot identified c2f6ea38fc ("mm: page_alloc: don't steal
single pages from biggest buddy") as the root cause of a 56.4% regression
in vm-scalability::lru-file-mmap-read.
Carlos reports an earlier patch, c0cd6f557b ("mm: page_alloc: fix
freelist movement during block conversion"), as the root cause for a
regression in worst-case zone->lock+irqoff hold times.
Both of these patches modify the page allocator's fallback path to be less
greedy in an effort to stave off fragmentation. The flip side of this is
that fallbacks are also less productive each time around, which means the
fallback search can run much more frequently.
Carlos' traces point to rmqueue_bulk() specifically, which tries to refill
the percpu cache by allocating a large batch of pages in a loop. It
highlights how once the native freelists are exhausted, the fallback code
first scans orders top-down for whole blocks to claim, then falls back to
a bottom-up search for the smallest buddy to steal. For the next batch
page, it goes through the same thing again.
This can be made more efficient. Since rmqueue_bulk() holds the
zone->lock over the entire batch, the freelists are not subject to outside
changes; when the search for a block to claim has already failed, there is
no point in trying again for the next page.
Modify __rmqueue() to remember the last successful fallback mode, and
restart directly from there on the next rmqueue_bulk() iteration.
Oliver confirms that this improves beyond the regression that the test
robot reported against c2f6ea38fc1b:
commit:
f3b92176f4 ("tools/selftests: add guard region test for /proc/$pid/pagemap")
c2f6ea38fc ("mm: page_alloc: don't steal single pages from biggest buddy")
acc4d5ff0b ("Merge tag 'net-6.15-rc0' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net")
2c847f27c3 ("mm: page_alloc: speed up fallbacks in rmqueue_bulk()") <--- your patch
f3b92176f4c2f6ea38fcacc4d5ff0b 2c847f27c37da65a93d23c237c5
---------------- --------------------------- --------------------------- ---------------------------
%stddev %change %stddev %change %stddev %change %stddev
\ | \ | \ | \
25525364 ± 3% -56.4% 11135467 -57.8% 10779336 +31.6% 33581409 vm-scalability.throughput
Carlos confirms that worst-case times are almost fully recovered
compared to before the earlier culprit patch:
2dd482ba62 (before freelist hygiene): 1ms
c0cd6f557b (after freelist hygiene): 90ms
next-20250319 (steal smallest buddy): 280ms
this patch : 8ms
[jackmanb@google.com: comment updates]
Link: https://lkml.kernel.org/r/D92AC0P9594X.3BML64MUKTF8Z@google.com
[hannes@cmpxchg.org: reset rmqueue_mode in rmqueue_buddy() error loop, per Yunsheng Lin]
Link: https://lkml.kernel.org/r/20250409140023.GA2313@cmpxchg.org
Link: https://lkml.kernel.org/r/20250407180154.63348-1-hannes@cmpxchg.org
Fixes: c0cd6f557b ("mm: page_alloc: fix freelist movement during block conversion")
Fixes: c2f6ea38fc ("mm: page_alloc: don't steal single pages from biggest buddy")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Brendan Jackman <jackmanb@google.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Reported-by: Carlos Song <carlos.song@nxp.com>
Tested-by: Carlos Song <carlos.song@nxp.com>
Tested-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202503271547.fc08b188-lkp@intel.com
Reviewed-by: Brendan Jackman <jackmanb@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org> [6.10+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c2f6ea38fc upstream.
The fallback code searches for the biggest buddy first in an attempt to
steal the whole block and encourage type grouping down the line.
The approach used to be this:
- Non-movable requests will split the largest buddy and steal the
remainder. This splits up contiguity, but it allows subsequent
requests of this type to fall back into adjacent space.
- Movable requests go and look for the smallest buddy instead. The
thinking is that movable requests can be compacted, so grouping is
less important than retaining contiguity.
c0cd6f557b ("mm: page_alloc: fix freelist movement during block
conversion") enforces freelist type hygiene, which restricts stealing to
either claiming the whole block or just taking the requested chunk; no
additional pages or buddy remainders can be stolen any more.
The patch mishandled when to switch to finding the smallest buddy in that
new reality. As a result, it may steal the exact request size, but from
the biggest buddy. This causes fracturing for no good reason.
Fix this by committing to the new behavior: either steal the whole block,
or fall back to the smallest buddy.
Remove single-page stealing from steal_suitable_fallback(). Rename it to
try_to_steal_block() to make the intentions clear. If this fails, always
fall back to the smallest buddy.
The following is from 4 runs of mmtest's thpchallenge. "Pollute" is
single page fallback, "steal" is conversion of a partially used block.
The numbers for free block conversions (omitted) are comparable.
vanilla patched
@pollute[unmovable from reclaimable]: 27 106
@pollute[unmovable from movable]: 82 46
@pollute[reclaimable from unmovable]: 256 83
@pollute[reclaimable from movable]: 46 8
@pollute[movable from unmovable]: 4841 868
@pollute[movable from reclaimable]: 5278 12568
@steal[unmovable from reclaimable]: 11 12
@steal[unmovable from movable]: 113 49
@steal[reclaimable from unmovable]: 19 34
@steal[reclaimable from movable]: 47 21
@steal[movable from unmovable]: 250 183
@steal[movable from reclaimable]: 81 93
The allocator appears to do a better job at keeping stealing and polluting
to the first fallback preference. As a result, the numbers for "from
movable" - the least preferred fallback option, and most detrimental to
compactability - are down across the board.
Link: https://lkml.kernel.org/r/20250225001023.1494422-2-hannes@cmpxchg.org
Fixes: c0cd6f557b ("mm: page_alloc: fix freelist movement during block conversion")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Brendan Jackman <jackmanb@google.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit da8bf5daa5 upstream.
When increasing the array size in memblock_double_array() and the slab
is not yet available, a call to memblock_find_in_range() is used to
reserve/allocate memory. However, the range returned may not have been
accepted, which can result in a crash when booting an SNP guest:
RIP: 0010:memcpy_orig+0x68/0x130
Code: ...
RSP: 0000:ffffffff9cc03ce8 EFLAGS: 00010006
RAX: ff11001ff83e5000 RBX: 0000000000000000 RCX: fffffffffffff000
RDX: 0000000000000bc0 RSI: ffffffff9dba8860 RDI: ff11001ff83e5c00
RBP: 0000000000002000 R08: 0000000000000000 R09: 0000000000002000
R10: 000000207fffe000 R11: 0000040000000000 R12: ffffffff9d06ef78
R13: ff11001ff83e5000 R14: ffffffff9dba7c60 R15: 0000000000000c00
memblock_double_array+0xff/0x310
memblock_add_range+0x1fb/0x2f0
memblock_reserve+0x4f/0xa0
memblock_alloc_range_nid+0xac/0x130
memblock_alloc_internal+0x53/0xc0
memblock_alloc_try_nid+0x3d/0xa0
swiotlb_init_remap+0x149/0x2f0
mem_init+0xb/0xb0
mm_core_init+0x8f/0x350
start_kernel+0x17e/0x5d0
x86_64_start_reservations+0x14/0x30
x86_64_start_kernel+0x92/0xa0
secondary_startup_64_no_verify+0x194/0x19b
Mitigate this by calling accept_memory() on the memory range returned
before the slab is available.
Prior to v6.12, the accept_memory() interface used a 'start' and 'end'
parameter instead of 'start' and 'size', therefore the accept_memory()
call must be adjusted to specify 'start + size' for 'end' when applying
to kernels prior to v6.12.
Cc: stable@vger.kernel.org # see patch description, needs adjustments for <= 6.11
Fixes: dcdfdd40fa ("mm: Add support for unaccepted memory")
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/da1ac73bf4ded761e21b4e4bb5178382a580cd73.1746725050.git.thomas.lendacky@amd.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit be6e843fc5 upstream.
When migrating a THP, concurrent access to the PMD migration entry during
a deferred split scan can lead to an invalid address access, as
illustrated below. To prevent this invalid access, it is necessary to
check the PMD migration entry and return early. In this context, there is
no need to use pmd_to_swp_entry and pfn_swap_entry_to_page to verify the
equality of the target folio. Since the PMD migration entry is locked, it
cannot be served as the target.
Mailing list discussion and explanation from Hugh Dickins: "An anon_vma
lookup points to a location which may contain the folio of interest, but
might instead contain another folio: and weeding out those other folios is
precisely what the "folio != pmd_folio((*pmd)" check (and the "risk of
replacing the wrong folio" comment a few lines above it) is for."
BUG: unable to handle page fault for address: ffffea60001db008
CPU: 0 UID: 0 PID: 2199114 Comm: tee Not tainted 6.14.0+ #4 NONE
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:split_huge_pmd_locked+0x3b5/0x2b60
Call Trace:
<TASK>
try_to_migrate_one+0x28c/0x3730
rmap_walk_anon+0x4f6/0x770
unmap_folio+0x196/0x1f0
split_huge_page_to_list_to_order+0x9f6/0x1560
deferred_split_scan+0xac5/0x12a0
shrinker_debugfs_scan_write+0x376/0x470
full_proxy_write+0x15c/0x220
vfs_write+0x2fc/0xcb0
ksys_write+0x146/0x250
do_syscall_64+0x6a/0x120
entry_SYSCALL_64_after_hwframe+0x76/0x7e
The bug is found by syzkaller on an internal kernel, then confirmed on
upstream.
Link: https://lkml.kernel.org/r/20250421113536.3682201-1-gavinguo@igalia.com
Link: https://lore.kernel.org/all/20250414072737.1698513-1-gavinguo@igalia.com/
Link: https://lore.kernel.org/all/20250418085802.2973519-1-gavinguo@igalia.com/
Fixes: 84c3fc4e9c ("mm: thp: check pmd migration entry in common path")
Signed-off-by: Gavin Guo <gavinguo@igalia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Cc: Florent Revest <revest@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a0309faf1c upstream.
Introduce struct vm_struct::requested_size so that the requested
(re)allocation size is retained separately from the allocated area size.
This means that KASAN will correctly poison the correct spans of requested
bytes. This also means we can support growing the usable portion of an
allocation that can already be supported by the existing area's existing
allocation.
Link: https://lkml.kernel.org/r/20250426001105.it.679-kees@kernel.org
Fixes: 3ddc2fefe6 ("mm: vmalloc: implement vrealloc()")
Signed-off-by: Kees Cook <kees@kernel.org>
Reported-by: Erhard Furtner <erhard_f@mailbox.org>
Closes: https://lore.kernel.org/all/20250408192503.6149a816@outsider.home/
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7b08b74f3d upstream.
On XEN PV, folio_pte_batch() can incorrectly batch beyond the end of a
folio due to a corner case in pte_advance_pfn(). Specifically, when the
PFN following the folio maps to an invalidated MFN,
expected_pte = pte_advance_pfn(expected_pte, nr);
produces a pte_none(). If the actual next PTE in memory is also
pte_none(), the pte_same() succeeds,
if (!pte_same(pte, expected_pte))
break;
the loop is not broken, and batching continues into unrelated memory.
For example, with a 4-page folio, the PTE layout might look like this:
[ 53.465673] [ T2552] folio_pte_batch: printing PTE values at addr=0x7f1ac9dc5000
[ 53.465674] [ T2552] PTE[453] = 000000010085c125
[ 53.465679] [ T2552] PTE[454] = 000000010085d125
[ 53.465682] [ T2552] PTE[455] = 000000010085e125
[ 53.465684] [ T2552] PTE[456] = 000000010085f125
[ 53.465686] [ T2552] PTE[457] = 0000000000000000 <-- not present
[ 53.465689] [ T2552] PTE[458] = 0000000101da7125
pte_advance_pfn(PTE[456]) returns a pte_none() due to invalid PFN->MFN
mapping. The next actual PTE (PTE[457]) is also pte_none(), so the loop
continues and includes PTE[457] in the batch, resulting in 5 batched
entries for a 4-page folio. This triggers the following warning:
[ 53.465751] [ T2552] page: refcount:85 mapcount:20 mapping:ffff88813ff4f6a8 index:0x110 pfn:0x10085c
[ 53.465754] [ T2552] head: order:2 mapcount:80 entire_mapcount:0 nr_pages_mapped:4 pincount:0
[ 53.465756] [ T2552] memcg:ffff888003573000
[ 53.465758] [ T2552] aops:0xffffffff8226fd20 ino:82467c dentry name(?):"libc.so.6"
[ 53.465761] [ T2552] flags: 0x2000000000416c(referenced|uptodate|lru|active|private|head|node=0|zone=2)
[ 53.465764] [ T2552] raw: 002000000000416c ffffea0004021f08 ffffea0004021908 ffff88813ff4f6a8
[ 53.465767] [ T2552] raw: 0000000000000110 ffff888133d8bd40 0000005500000013 ffff888003573000
[ 53.465768] [ T2552] head: 002000000000416c ffffea0004021f08 ffffea0004021908 ffff88813ff4f6a8
[ 53.465770] [ T2552] head: 0000000000000110 ffff888133d8bd40 0000005500000013 ffff888003573000
[ 53.465772] [ T2552] head: 0020000000000202 ffffea0004021701 000000040000004f 00000000ffffffff
[ 53.465774] [ T2552] head: 0000000300000003 8000000300000002 0000000000000013 0000000000000004
[ 53.465775] [ T2552] page dumped because: VM_WARN_ON_FOLIO((_Generic((page + nr_pages - 1), const struct page *: (const struct folio *)_compound_head(page + nr_pages - 1), struct page *: (struct folio *)_compound_head(page + nr_pages - 1))) != folio)
Original code works as expected everywhere, except on XEN PV, where
pte_advance_pfn() can yield a pte_none() after balloon inflation due to
MFNs invalidation. In XEN, pte_advance_pfn() ends up calling
__pte()->xen_make_pte()->pte_pfn_to_mfn(), which returns pte_none() when
mfn == INVALID_P2M_ENTRY.
The pte_pfn_to_mfn() documents that nastiness:
If there's no mfn for the pfn, then just create an
empty non-present pte. Unfortunately this loses
information about the original pfn, so
pte_mfn_to_pfn is asymmetric.
While such hacks should certainly be removed, we can do better in
folio_pte_batch() and simply check ahead of time how many PTEs we can
possibly batch in our folio.
This way, we can not only fix the issue but cleanup the code: removing the
pte_pfn() check inside the loop body and avoiding end_ptr comparison +
arithmetic.
Link: https://lkml.kernel.org/r/20250502215019.822-2-arkamar@atlas.cz
Fixes: f8d937761d ("mm/memory: optimize fork() with PTE-mapped THP")
Co-developed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Petr Vaněk <arkamar@atlas.cz>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit be8250786c upstream.
When memory allocation profiling is disabled at runtime or due to an
error, shutdown_mem_profiling() is called: slab->obj_exts which
previously allocated remains.
It won't be cleared by unaccount_slab() because of
mem_alloc_profiling_enabled() not true. It's incorrect, slab->obj_exts
should always be cleaned up in unaccount_slab() to avoid following error:
[...]BUG: Bad page state in process...
..
[...]page dumped because: page still charged to cgroup
[andriy.shevchenko@linux.intel.com: fold need_slab_obj_ext() into its only user]
Fixes: 21c690a349 ("mm: introduce slabobj_ext to support slab object extensions")
Cc: stable@vger.kernel.org
Signed-off-by: Zhenhua Huang <quic_zhenhuah@quicinc.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Harry Yoo <harry.yoo@oracle.com>
Tested-by: Harry Yoo <harry.yoo@oracle.com>
Acked-by: Suren Baghdasaryan <surenb@google.com>
Link: https://patch.msgid.link/20250421075232.2165527-1-quic_zhenhuah@quicinc.com
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
[surenb: fixed trivial merge conflict in alloc_tagging_slab_alloc_hook(),
skipped inlining free_slab_obj_exts() as it's already inline in 6.12]
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit eac8ea8736 upstream.
Commit 61167ad5fe ("mm: pass nid to reserve_bootmem_region()") introduce
a way to set nid to all reserved region.
But there is a corner case it will leave some region with invalid nid.
When memblock_set_node() doubles the array of memblock.reserved, it may
lead to a new reserved region before current position. The new region
will be left with an invalid node id.
Repeat the process when detecting it.
Fixes: 61167ad5fe ("mm: pass nid to reserve_bootmem_region()")
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
CC: Mike Rapoport <rppt@kernel.org>
CC: Yajun Deng <yajun.deng@linux.dev>
CC: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20250318071948.23854-3-richard.weiyang@gmail.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 06eaa824fd upstream.
The second parameter of memblock_set_node() is size instead of end.
Since it iterates from lower address to higher address, finally the node
id is correct. But during the process, some of them are wrong.
Pass size instead of end.
Fixes: 61167ad5fe ("mm: pass nid to reserve_bootmem_region()")
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
CC: Mike Rapoport <rppt@kernel.org>
CC: Yajun Deng <yajun.deng@linux.dev>
CC: stable@vger.kernel.org
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/r/20250318071948.23854-2-richard.weiyang@gmail.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 1b0449544c ]
Syzkaller reports a bug as follows:
Injecting memory failure for pfn 0x18b00e at process virtual address 0x20ffd000
Memory failure: 0x18b00e: dirty swapcache page still referenced by 2 users
Memory failure: 0x18b00e: recovery action for dirty swapcache page: Failed
page: refcount:2 mapcount:0 mapping:0000000000000000 index:0x20ffd pfn:0x18b00e
memcg:ffff0000dd6d9000
anon flags: 0x5ffffe00482011(locked|dirty|arch_1|swapbacked|hwpoison|node=0|zone=2|lastcpupid=0xfffff)
raw: 005ffffe00482011 dead000000000100 dead000000000122 ffff0000e232a7c9
raw: 0000000000020ffd 0000000000000000 00000002ffffffff ffff0000dd6d9000
page dumped because: VM_BUG_ON_FOLIO(!folio_test_uptodate(folio))
------------[ cut here ]------------
kernel BUG at mm/swap_state.c:184!
Internal error: Oops - BUG: 00000000f2000800 [#1] SMP
Modules linked in:
CPU: 0 PID: 60 Comm: kswapd0 Not tainted 6.6.0-gcb097e7de84e #3
Hardware name: linux,dummy-virt (DT)
pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : add_to_swap+0xbc/0x158
lr : add_to_swap+0xbc/0x158
sp : ffff800087f37340
x29: ffff800087f37340 x28: fffffc00052c0380 x27: ffff800087f37780
x26: ffff800087f37490 x25: ffff800087f37c78 x24: ffff800087f377a0
x23: ffff800087f37c50 x22: 0000000000000000 x21: fffffc00052c03b4
x20: 0000000000000000 x19: fffffc00052c0380 x18: 0000000000000000
x17: 296f696c6f662865 x16: 7461646f7470755f x15: 747365745f6f696c
x14: 6f6621284f494c4f x13: 0000000000000001 x12: ffff600036d8b97b
x11: 1fffe00036d8b97a x10: ffff600036d8b97a x9 : dfff800000000000
x8 : 00009fffc9274686 x7 : ffff0001b6c5cbd3 x6 : 0000000000000001
x5 : ffff0000c25896c0 x4 : 0000000000000000 x3 : 0000000000000000
x2 : 0000000000000000 x1 : ffff0000c25896c0 x0 : 0000000000000000
Call trace:
add_to_swap+0xbc/0x158
shrink_folio_list+0x12ac/0x2648
shrink_inactive_list+0x318/0x948
shrink_lruvec+0x450/0x720
shrink_node_memcgs+0x280/0x4a8
shrink_node+0x128/0x978
balance_pgdat+0x4f0/0xb20
kswapd+0x228/0x438
kthread+0x214/0x230
ret_from_fork+0x10/0x20
I can reproduce this issue with the following steps:
1) When a dirty swapcache page is isolated by reclaim process and the
page isn't locked, inject memory failure for the page.
me_swapcache_dirty() clears uptodate flag and tries to delete from lru,
but fails. Reclaim process will put the hwpoisoned page back to lru.
2) The process that maps the hwpoisoned page exits, the page is deleted
the page will never be freed and will be in the lru forever.
3) If we trigger a reclaim again and tries to reclaim the page,
add_to_swap() will trigger VM_BUG_ON_FOLIO due to the uptodate flag is
cleared.
To fix it, skip the hwpoisoned page in shrink_folio_list(). Besides, the
hwpoison folio may not be unmapped by hwpoison_user_mappings() yet, unmap
it in shrink_folio_list(), otherwise the folio will fail to be unmaped by
hwpoison_user_mappings() since the folio isn't in lru list.
Link: https://lkml.kernel.org/r/20250318083939.987651-3-tujinjiang@huawei.com
Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: <stable@vger,kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 41e6ddcaa0 upstream.
Currently, if a VMA merge fails due to an OOM condition arising on commit
merge or a failure to duplicate anon_vma's, we report this so the caller
can handle it.
However there are cases where the caller is only ostensibly trying a
merge, and doesn't mind if it fails due to this condition.
Since we do not want to introduce an implicit assumption that we only
actually modify VMAs after OOM conditions might arise, add a 'give up on
oom' option and make an explicit contract that, should this flag be set, we
absolutely will not modify any VMAs should OOM arise and just bail out.
Since it'd be very unusual for a user to try to vma_modify() with this flag
set but be specifying a range within a VMA which ends up being split (which
can fail due to rlimit issues, not only OOM), we add a debug warning for
this condition.
The motivating reason for this is uffd release - syzkaller (and Pedro
Falcato's VERY astute analysis) found a way in which an injected fault on
allocation, triggering an OOM condition on commit merge, would result in
uffd code becoming confused and treating an error value as if it were a VMA
pointer.
To avoid this, we make use of this new VMG flag to ensure that this never
occurs, utilising the fact that, should we be clearing entire VMAs, we do
not wish an OOM event to be reported to us.
Many thanks to Pedro Falcato for his excellent analysis and Jann Horn for
his insightful and intelligent analysis of the situation, both of whom were
instrumental in this fix.
Link: https://lkml.kernel.org/r/20250321100937.46634-1-lorenzo.stoakes@oracle.com
Reported-by: syzbot+20ed41006cf9d842c2b5@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/67dc67f0.050a0220.25ae54.001e.GAE@google.com/
Fixes: 47b16d0462 ("mm: abort vma_modify() on merge out of memory failure")
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Suggested-by: Pedro Falcato <pfalcato@suse.de>
Suggested-by: Jann Horn <jannh@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a995199384 upstream.
In the case of apply_to_existing_page_range(), apply_to_pte_range() is
reached with 'create' set to false. When !create, the loop over the PTE
page table is broken.
apply_to_pte_range() will only move to the next PTE entry if 'create' is
true or if the current entry is not pte_none().
This means that the user of apply_to_existing_page_range() will not have
'fn' called for any entries after the first pte_none() in the PTE page
table.
Fix the loop logic in apply_to_pte_range().
There are no known runtime issues from this, but the fix is trivial enough
for stable@ even without a known buggy user.
Link: https://lkml.kernel.org/r/20250409094043.1629234-1-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Fixes: be1db4753e ("mm/memory.c: add apply_to_existing_page_range() helper")
Cc: Daniel Axtens <dja@axtens.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8ab1b16023 upstream.
filemap_get_folios_contig() is supposed to return distinct folios found
within [start, end]. Large folios in the Xarray become multi-index
entries. xas_next() can iterate through the sub-indexes before finding a
sibling entry and breaking out of the loop.
This can result in a returned folio_batch containing an indeterminate
number of duplicate folios, which forces the callers to skeptically handle
the returned batch. This is inefficient and incurs a large maintenance
overhead.
We can fix this by calling xas_advance() after we have successfully adding
a folio to the batch to ensure our Xarray is positioned such that it will
correctly find the next folio - similar to filemap_get_read_batch().
Link: https://lkml.kernel.org/r/Z-8s1-kiIDkzgRbc@fedora
Fixes: 35b471467f ("filemap: add filemap_get_folios_contig()")
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reported-by: Qu Wenruo <quwenruo.btrfs@gmx.com>
Closes: https://lkml.kernel.org/r/b714e4de-2583-4035-b829-72cfb5eb6fc6@gmx.com
Tested-by: Qu Wenruo <quwenruo.btrfs@gmx.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vivek Kasireddy <vivek.kasireddy@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8c03ebd7cd upstream.
Not like fault_in_readable() or fault_in_writeable(), in
fault_in_safe_writeable() local variable 'start' is increased page by page
to loop till the whole address range is handled. However, it mistakenly
calculates the size of the handled range with 'uaddr - start'.
Fix it here.
Andreas said:
: In gfs2, fault_in_iov_iter_writeable() is used in
: gfs2_file_direct_read() and gfs2_file_read_iter(), so this potentially
: affects buffered as well as direct reads. This bug could cause those
: gfs2 functions to spin in a loop.
Link: https://lkml.kernel.org/r/20250410035717.473207-1-bhe@redhat.com
Link: https://lkml.kernel.org/r/20250410035717.473207-2-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Fixes: fe673d3f5b ("mm: gup: make fault_in_safe_writeable() use fixup_user_fault()")
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Yanjun.Zhu <yanjun.zhu@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a84edd52f0 upstream.
The compaction code doesn't take references on pages until we're certain
we should attempt to handle it.
In the hugetlb case, isolate_or_dissolve_huge_page() may return -EBUSY
without taking a reference to the folio associated with our pfn. If our
folio's refcount drops to 0, compound_nr() becomes unpredictable, making
low_pfn and nr_scanned unreliable. The user-visible effect is minimal -
this should rarely happen (if ever).
Fix this by storing the folio statistics earlier on the stack (just like
the THP and Buddy cases).
Also revert commit 66fe1cf7f5 ("mm: compaction: use helper compound_nr
in isolate_migratepages_block") to make backporting easier.
Link: https://lkml.kernel.org/r/20250401021025.637333-1-vishal.moola@gmail.com
Fixes: 369fa227c2 ("mm: make alloc_contig_range handle free hugetlb pages")
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 5f5ee52d4f upstream.
Patch series "mm/vmscan: don't try to reclaim hwpoison folio".
Fix a bug during memory reclaim if folio is hwpoisoned.
This patch (of 2):
Introduce helper folio_contain_hwpoisoned_page() to check if the entire
folio is hwpoisoned or it contains hwpoisoned pages.
Link: https://lkml.kernel.org/r/20250318083939.987651-1-tujinjiang@huawei.com
Link: https://lkml.kernel.org/r/20250318083939.987651-2-tujinjiang@huawei.com
Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 1ca77ff183 upstream.
hugetlb_sysctl_init() is only invoked once by an __init function and is
merely a wrapper around another __init function so there is not reason to
keep it.
Fixes the following warning when toning down some GCC inline options:
WARNING: modpost: vmlinux: section mismatch in reference:
hugetlb_sysctl_init+0x1b (section: .text) ->
__register_sysctl_init (section: .init.text)
Link: https://lkml.kernel.org/r/20250319060041.2737320-1-marc.herbert@linux.intel.com
Signed-off-by: Marc Herbert <Marc.Herbert@linux.intel.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit aaf99ac2ce upstream.
When an uncorrected memory error is consumed there is a race between the
CMCI from the memory controller reporting an uncorrected error with a UCNA
signature, and the core reporting and SRAR signature machine check when
the data is about to be consumed.
- Background: why *UN*corrected errors tied to *C*MCI in Intel platform [1]
Prior to Icelake memory controllers reported patrol scrub events that
detected a previously unseen uncorrected error in memory by signaling a
broadcast machine check with an SRAO (Software Recoverable Action
Optional) signature in the machine check bank. This was overkill because
it's not an urgent problem that no core is on the verge of consuming that
bad data. It's also found that multi SRAO UCE may cause nested MCE
interrupts and finally become an IERR.
Hence, Intel downgrades the machine check bank signature of patrol scrub
from SRAO to UCNA (Uncorrected, No Action required), and signal changed to
#CMCI. Just to add to the confusion, Linux does take an action (in
uc_decode_notifier()) to try to offline the page despite the UC*NA*
signature name.
- Background: why #CMCI and #MCE race when poison is consuming in Intel platform [1]
Having decided that CMCI/UCNA is the best action for patrol scrub errors,
the memory controller uses it for reads too. But the memory controller is
executing asynchronously from the core, and can't tell the difference
between a "real" read and a speculative read. So it will do CMCI/UCNA if
an error is found in any read.
Thus:
1) Core is clever and thinks address A is needed soon, issues a speculative read.
2) Core finds it is going to use address A soon after sending the read request
3) The CMCI from the memory controller is in a race with MCE from the core
that will soon try to retire the load from address A.
Quite often (because speculation has got better) the CMCI from the memory
controller is delivered before the core is committed to the instruction
reading address A, so the interrupt is taken, and Linux offlines the page
(marking it as poison).
- Why user process is killed for instr case
Commit 046545a661 ("mm/hwpoison: fix error page recovered but reported
"not recovered"") tries to fix noise message "Memory error not recovered"
and skips duplicate SIGBUSs due to the race. But it also introduced a bug
that kill_accessing_process() return -EHWPOISON for instr case, as result,
kill_me_maybe() send a SIGBUS to user process.
If the CMCI wins that race, the page is marked poisoned when
uc_decode_notifier() calls memory_failure(). For dirty pages,
memory_failure() invokes try_to_unmap() with the TTU_HWPOISON flag,
converting the PTE to a hwpoison entry. As a result,
kill_accessing_process():
- call walk_page_range() and return 1 regardless of whether
try_to_unmap() succeeds or fails,
- call kill_proc() to make sure a SIGBUS is sent
- return -EHWPOISON to indicate that SIGBUS is already sent to the
process and kill_me_maybe() doesn't have to send it again.
However, for clean pages, the TTU_HWPOISON flag is cleared, leaving the
PTE unchanged and not converted to a hwpoison entry. Conversely, for
clean pages where PTE entries are not marked as hwpoison,
kill_accessing_process() returns -EFAULT, causing kill_me_maybe() to send
a SIGBUS.
Console log looks like this:
Memory failure: 0x827ca68: corrupted page was clean: dropped without side effects
Memory failure: 0x827ca68: recovery action for clean LRU page: Recovered
Memory failure: 0x827ca68: already hardware poisoned
mce: Memory error not recovered
To fix it, return 0 for "corrupted page was clean", preventing an
unnecessary SIGBUS to user process.
[1] https://lore.kernel.org/lkml/20250217063335.22257-1-xueshuai@linux.alibaba.com/T/#mba94f1305b3009dd340ce4114d3221fe810d1871
Link: https://lkml.kernel.org/r/20250312112852.82415-3-xueshuai@linux.alibaba.com
Fixes: 046545a661 ("mm/hwpoison: fix error page recovered but reported "not recovered"")
Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com>
Tested-by: Tony Luck <tony.luck@intel.com>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Jarkko Sakkinen <jarkko@kernel.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ruidong Tian <tianruidong@linux.alibaba.com>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Yazen Ghannam <yazen.ghannam@amd.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c0ebbb3841 upstream.
The PGDAT_RECLAIM_LOCKED bit is used to provide mutual exclusion of node
reclaim for struct pglist_data using a single bit.
It is "locked" with a test_and_set_bit (similarly to a try lock) which
provides full ordering with respect to loads and stores done within
__node_reclaim().
It is "unlocked" with clear_bit(), which does not provide any ordering
with respect to loads and stores done before clearing the bit.
The lack of clear_bit() memory ordering with respect to stores within
__node_reclaim() can cause a subsequent CPU to fail to observe stores from
a prior node reclaim. This is not an issue in practice on TSO (e.g.
x86), but it is an issue on weakly-ordered architectures (e.g. arm64).
Fix this by using clear_bit_unlock rather than clear_bit to clear
PGDAT_RECLAIM_LOCKED with a release memory ordering semantic.
This provides stronger memory ordering (release rather than relaxed).
Link: https://lkml.kernel.org/r/20250312141014.129725-1-mathieu.desnoyers@efficios.com
Fixes: d773ed6b85 ("mm: test and set zone reclaim lock before starting reclaim")
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Andrea Parri <parri.andrea@gmail.com>
Cc: Will Deacon <will@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Jade Alglave <j.alglave@ucl.ac.uk>
Cc: Luc Maranget <luc.maranget@inria.fr>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 937582ee8e upstream.
Patch series "refactor mremap and fix bug", v3.
The existing mremap() logic has grown organically over a very long period
of time, resulting in code that is in many parts, very difficult to follow
and full of subtleties and sources of confusion.
In addition, it is difficult to thread state through the operation
correctly, as function arguments have expanded, some parameters are
expected to be temporarily altered during the operation, others are
intended to remain static and some can be overridden.
This series completely refactors the mremap implementation, sensibly
separating functions, adding comments to explain the more subtle aspects
of the implementation and making use of small structs to thread state
through everything.
The reason for doing so is to lay the groundwork for planned future
changes to the mremap logic, changes which require the ability to easily
pass around state.
Additionally, it would be unhelpful to add yet more logic to code that is
already difficult to follow without first refactoring it like this.
The first patch in this series additionally fixes a bug when a VMA with
start address zero is partially remapped.
Tested on real hardware under heavy workload and all self tests are
passing.
This patch (of 3):
Consider the case of a partial mremap() (that results in a VMA split) of
an accountable VMA (i.e. which has the VM_ACCOUNT flag set) whose start
address is zero, with the MREMAP_MAYMOVE flag specified and a scenario
where a move does in fact occur:
addr end
| |
v v
|-------------|
| vma |
|-------------|
0
This move is affected by unmapping the range [addr, end). In order to
prevent an incorrect decrement of accounted memory which has already been
determined, the mremap() code in move_vma() clears VM_ACCOUNT from the VMA
prior to doing so, before reestablishing it in each of the VMAs
post-split:
addr end
| |
v v
|---| |---|
| A | | B |
|---| |---|
Commit 6b73cff239 ("mm: change munmap splitting order and move_vma()")
changed this logic such as to determine whether there is a need to do so
by establishing account_start and account_end and, in the instance where
such an operation is required, assigning them to vma->vm_start and
vma->vm_end.
Later the code checks if the operation is required for 'A' referenced
above thusly:
if (account_start) {
...
}
However, if the VMA described above has vma->vm_start == 0, which is now
assigned to account_start, this branch will not be executed.
As a result, the VMA 'A' above will remain stripped of its VM_ACCOUNT
flag, incorrectly.
The fix is to simply convert these variables to booleans and set them as
required.
Link: https://lkml.kernel.org/r/cover.1741639347.git.lorenzo.stoakes@oracle.com
Link: https://lkml.kernel.org/r/dc55cb6db25d97c3d9e460de4986a323fa959676.1741639347.git.lorenzo.stoakes@oracle.com
Fixes: 6b73cff239 ("mm: change munmap splitting order and move_vma()")
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Harry Yoo <harry.yoo@oracle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 442b1eca22 upstream.
When a process consumes a UE in a page, the memory failure handler
attempts to collect information for a potential SIGBUS. If the page is an
anonymous page, page_mapped_in_vma(page, vma) is invoked in order to
1. retrieve the vaddr from the process' address space,
2. verify that the vaddr is indeed mapped to the poisoned page,
where 'page' is the precise small page with UE.
It's been observed that when injecting poison to a non-head subpage of an
anonymous hugetlb page, no SIGBUS shows up, while injecting to the head
page produces a SIGBUS. The cause is that, though hugetlb_walk() returns
a valid pmd entry (on x86), but check_pte() detects mismatch between the
head page per the pmd and the input subpage. Thus the vaddr is considered
not mapped to the subpage and the process is not collected for SIGBUS
purpose. This is the calling stack:
collect_procs_anon
page_mapped_in_vma
page_vma_mapped_walk
hugetlb_walk
huge_pte_lock
check_pte
check_pte() header says that it
"check if [pvmw->pfn, @pvmw->pfn + @pvmw->nr_pages) is mapped at the @pvmw->pte"
but practically works only if pvmw->pfn is the head page pfn at pvmw->pte.
Hindsight acknowledging that some pvmw->pte could point to a hugepage of
some sort such that it makes sense to make check_pte() work for hugepage.
Link: https://lkml.kernel.org/r/20250224211445.2663312-1-jane.chu@oracle.com
Signed-off-by: Jane Chu <jane.chu@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shuemov <kirill.shutemov@linux.intel.com>
Cc: linmiaohe <linmiaohe@huawei.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit bc3fe6805c upstream.
Even though FOLL_SPLIT_PMD on hugetlb now always fails with -EOPNOTSUPP,
let's add a safety net in case FOLL_SPLIT_PMD usage would ever be
reworked.
In particular, before commit 9cb28da546 ("mm/gup: handle hugetlb in the
generic follow_page_mask code"), GUP(FOLL_SPLIT_PMD) would just have
returned a page. In particular, hugetlb folios that are not PMD-sized
would never have been prone to FOLL_SPLIT_PMD.
hugetlb folios can be anonymous, and page_make_device_exclusive_one() is
not really prepared for handling them at all. So let's spell that out.
Link: https://lkml.kernel.org/r/20250210193801.781278-3-david@redhat.com
Fixes: b756a3b5e7 ("mm: device exclusive memory access")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Tested-by: Alistair Popple <apopple@nvidia.com>
Cc: Alex Shi <alexs@kernel.org>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Karol Herbst <kherbst@redhat.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Lyude <lyude@redhat.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Simona Vetter <simona.vetter@ffwll.ch>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yanteng Si <si.yanteng@linux.dev>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 3a06696305 upstream.
Patch series "mm/damon/paddr: fix large folios access and schemes handling".
DAMON operations set for physical address space, namely 'paddr', treats
tail pages as unaccessed always. It can also apply DAMOS action to a
large folio multiple times within single DAMOS' regions walking. As a
result, the monitoring output has poor quality and DAMOS works in
unexpected ways when large folios are being used. Fix those.
The patches were parts of Usama's hugepage_size DAMOS filter patch
series[1]. The first fix has collected from there with a slight commit
message change for the subject prefix. The second fix is re-written by SJ
and posted as an RFC before this series. The second one also got a slight
commit message change for the subject prefix.
[1] https://lore.kernel.org/20250203225604.44742-1-usamaarif642@gmail.com
[2] https://lore.kernel.org/20250206231103.38298-1-sj@kernel.org
This patch (of 2):
This effectively adds support for large folios in damon for paddr, as
damon_pa_mkold/young won't get a null folio from this function and won't
ignore it, hence access will be checked and reported. This also means
that larger folios will be considered for different DAMOS actions like
pageout, prioritization and migration. As these DAMOS actions will
consider larger folios, iterate through the region at folio_size and not
PAGE_SIZE intervals. This should not have an affect on vaddr, as
damon_young_pmd_entry considers pmd entries.
Link: https://lkml.kernel.org/r/20250207212033.45269-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20250207212033.45269-2-sj@kernel.org
Fixes: a28397beb5 ("mm/damon: implement primitives for physical address space monitoring")
Signed-off-by: Usama Arif <usamaarif642@gmail.com>
Signed-off-by: SeongJae Park <sj@kernel.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c11bcbc0a5 upstream.
Currently, zswap_cpu_comp_dead() calls crypto_free_acomp() while holding
the per-CPU acomp_ctx mutex. crypto_free_acomp() then holds scomp_lock
(through crypto_exit_scomp_ops_async()).
On the other hand, crypto_alloc_acomp_node() holds the scomp_lock (through
crypto_scomp_init_tfm()), and then allocates memory. If the allocation
results in reclaim, we may attempt to hold the per-CPU acomp_ctx mutex.
The above dependencies can cause an ABBA deadlock. For example in the
following scenario:
(1) Task A running on CPU #1:
crypto_alloc_acomp_node()
Holds scomp_lock
Enters reclaim
Reads per_cpu_ptr(pool->acomp_ctx, 1)
(2) Task A is descheduled
(3) CPU #1 goes offline
zswap_cpu_comp_dead(CPU #1)
Holds per_cpu_ptr(pool->acomp_ctx, 1))
Calls crypto_free_acomp()
Waits for scomp_lock
(4) Task A running on CPU #2:
Waits for per_cpu_ptr(pool->acomp_ctx, 1) // Read on CPU #1
DEADLOCK
Since there is no requirement to call crypto_free_acomp() with the per-CPU
acomp_ctx mutex held in zswap_cpu_comp_dead(), move it after the mutex is
unlocked. Also move the acomp_request_free() and kfree() calls for
consistency and to avoid any potential sublte locking dependencies in the
future.
With this, only setting acomp_ctx fields to NULL occurs with the mutex
held. This is similar to how zswap_cpu_comp_prepare() only initializes
acomp_ctx fields with the mutex held, after performing all allocations
before holding the mutex.
Opportunistically, move the NULL check on acomp_ctx so that it takes place
before the mutex dereference.
Link: https://lkml.kernel.org/r/20250226185625.2672936-1-yosry.ahmed@linux.dev
Fixes: 12dcb0ef54 ("mm: zswap: properly synchronize freeing resources during CPU hotunplug")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Co-developed-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev>
Reported-by: syzbot+1a517ccfcbc6a7ab0f82@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/67bcea51.050a0220.bbfd1.0096.GAE@google.com/
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: Chengming Zhou <chengming.zhou@linux.dev>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Tested-by: Nhat Pham <nphamcs@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Chris Murphy <lists@colorremedies.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8977752c80 upstream.
Patch series "mm: fixes for device-exclusive entries (hmm)", v2.
Discussing the PageTail() call in make_device_exclusive_range() with
Willy, I recently discovered [1] that device-exclusive handling does not
properly work with THP, making the hmm-tests selftests fail if THPs are
enabled on the system.
Looking into more details, I found that hugetlb is not properly fenced,
and I realized that something that was bugging me for longer -- how
device-exclusive entries interact with mapcounts -- completely breaks
migration/swapout/split/hwpoison handling of these folios while they have
device-exclusive PTEs.
The program below can be used to allocate 1 GiB worth of pages and making
them device-exclusive on a kernel with CONFIG_TEST_HMM.
Once they are device-exclusive, these folios cannot get swapped out
(proc$pid/smaps_rollup will always indicate 1 GiB RSS no matter how much
one forces memory reclaim), and when having a memory block onlined to
ZONE_MOVABLE, trying to offline it will loop forever and complain about
failed migration of a page that should be movable.
# echo offline > /sys/devices/system/memory/memory136/state
# echo online_movable > /sys/devices/system/memory/memory136/state
# ./hmm-swap &
... wait until everything is device-exclusive
# echo offline > /sys/devices/system/memory/memory136/state
[ 285.193431][T14882] page: refcount:2 mapcount:0 mapping:0000000000000000
index:0x7f20671f7 pfn:0x442b6a
[ 285.196618][T14882] memcg:ffff888179298000
[ 285.198085][T14882] anon flags: 0x5fff0000002091c(referenced|uptodate|
dirty|active|owner_2|swapbacked|node=1|zone=3|lastcpupid=0x7ff)
[ 285.201734][T14882] raw: ...
[ 285.204464][T14882] raw: ...
[ 285.207196][T14882] page dumped because: migration failure
[ 285.209072][T14882] page_owner tracks the page as allocated
[ 285.210915][T14882] page last allocated via order 0, migratetype
Movable, gfp_mask 0x140dca(GFP_HIGHUSER_MOVABLE|__GFP_COMP|__GFP_ZERO),
id 14926, tgid 14926 (hmm-swap), ts 254506295376, free_ts 227402023774
[ 285.216765][T14882] post_alloc_hook+0x197/0x1b0
[ 285.218874][T14882] get_page_from_freelist+0x76e/0x3280
[ 285.220864][T14882] __alloc_frozen_pages_noprof+0x38e/0x2740
[ 285.223302][T14882] alloc_pages_mpol+0x1fc/0x540
[ 285.225130][T14882] folio_alloc_mpol_noprof+0x36/0x340
[ 285.227222][T14882] vma_alloc_folio_noprof+0xee/0x1a0
[ 285.229074][T14882] __handle_mm_fault+0x2b38/0x56a0
[ 285.230822][T14882] handle_mm_fault+0x368/0x9f0
...
This series fixes all issues I found so far. There is no easy way to fix
without a bigger rework/cleanup. I have a bunch of cleanups on top (some
previous sent, some the result of the discussion in v1) that I will send
out separately once this landed and I get to it.
I wish we could just use some special present PROT_NONE PTEs instead of
these (non-present, non-none) fake-swap entries; but that just results in
the same problem we keep having (lack of spare PTE bits), and staring at
other similar fake-swap entries, that ship has sailed.
With this series, make_device_exclusive() doesn't actually belong into
mm/rmap.c anymore, but I'll leave moving that for another day.
I only tested this series with the hmm-tests selftests due to lack of HW,
so I'd appreciate some testing, especially if the interaction between two
GPUs wanting a device-exclusive entry works as expected.
<program>
#include <stdio.h>
#include <fcntl.h>
#include <stdint.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/ioctl.h>
#include <linux/types.h>
#include <linux/ioctl.h>
#define HMM_DMIRROR_EXCLUSIVE _IOWR('H', 0x05, struct hmm_dmirror_cmd)
struct hmm_dmirror_cmd {
__u64 addr;
__u64 ptr;
__u64 npages;
__u64 cpages;
__u64 faults;
};
const size_t size = 1 * 1024 * 1024 * 1024ul;
const size_t chunk_size = 2 * 1024 * 1024ul;
int main(void)
{
struct hmm_dmirror_cmd cmd;
size_t cur_size;
int fd, ret;
char *addr, *mirror;
fd = open("/dev/hmm_dmirror1", O_RDWR, 0);
if (fd < 0) {
perror("open failed\n");
exit(1);
}
addr = mmap(NULL, size, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (addr == MAP_FAILED) {
perror("mmap failed\n");
exit(1);
}
madvise(addr, size, MADV_NOHUGEPAGE);
memset(addr, 1, size);
mirror = malloc(chunk_size);
for (cur_size = 0; cur_size < size; cur_size += chunk_size) {
cmd.addr = (uintptr_t)addr + cur_size;
cmd.ptr = (uintptr_t)mirror;
cmd.npages = chunk_size / getpagesize();
ret = ioctl(fd, HMM_DMIRROR_EXCLUSIVE, &cmd);
if (ret) {
perror("ioctl failed\n");
exit(1);
}
}
pause();
return 0;
}
</program>
[1] https://lkml.kernel.org/r/25e02685-4f1d-47fa-be5b-01ff85bb0ce2@redhat.com
This patch (of 17):
We only have two FOLL_SPLIT_PMD users. While uprobe refuses hugetlb
early, make_device_exclusive_range() can end up getting called on hugetlb
VMAs.
Right now, this means that with a PMD-sized hugetlb page, we can end up
calling split_huge_pmd(), because pmd_trans_huge() also succeeds with
hugetlb PMDs.
For example, using a modified hmm-test selftest one can trigger:
[ 207.017134][T14945] ------------[ cut here ]------------
[ 207.018614][T14945] kernel BUG at mm/page_table_check.c:87!
[ 207.019716][T14945] Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI
[ 207.021072][T14945] CPU: 3 UID: 0 PID: ...
[ 207.023036][T14945] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-2.fc40 04/01/2014
[ 207.024834][T14945] RIP: 0010:page_table_check_clear.part.0+0x488/0x510
[ 207.026128][T14945] Code: ...
[ 207.029965][T14945] RSP: 0018:ffffc9000cb8f348 EFLAGS: 00010293
[ 207.031139][T14945] RAX: 0000000000000000 RBX: 00000000ffffffff RCX: ffffffff8249a0cd
[ 207.032649][T14945] RDX: ffff88811e883c80 RSI: ffffffff8249a357 RDI: ffff88811e883c80
[ 207.034183][T14945] RBP: ffff888105c0a050 R08: 0000000000000005 R09: 0000000000000000
[ 207.035688][T14945] R10: 00000000ffffffff R11: 0000000000000003 R12: 0000000000000001
[ 207.037203][T14945] R13: 0000000000000200 R14: 0000000000000001 R15: dffffc0000000000
[ 207.038711][T14945] FS: 00007f2783275740(0000) GS:ffff8881f4980000(0000) knlGS:0000000000000000
[ 207.040407][T14945] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 207.041660][T14945] CR2: 00007f2782c00000 CR3: 0000000132356000 CR4: 0000000000750ef0
[ 207.043196][T14945] PKRU: 55555554
[ 207.043880][T14945] Call Trace:
[ 207.044506][T14945] <TASK>
[ 207.045086][T14945] ? __die+0x51/0x92
[ 207.045864][T14945] ? die+0x29/0x50
[ 207.046596][T14945] ? do_trap+0x250/0x320
[ 207.047430][T14945] ? do_error_trap+0xe7/0x220
[ 207.048346][T14945] ? page_table_check_clear.part.0+0x488/0x510
[ 207.049535][T14945] ? handle_invalid_op+0x34/0x40
[ 207.050494][T14945] ? page_table_check_clear.part.0+0x488/0x510
[ 207.051681][T14945] ? exc_invalid_op+0x2e/0x50
[ 207.052589][T14945] ? asm_exc_invalid_op+0x1a/0x20
[ 207.053596][T14945] ? page_table_check_clear.part.0+0x1fd/0x510
[ 207.054790][T14945] ? page_table_check_clear.part.0+0x487/0x510
[ 207.055993][T14945] ? page_table_check_clear.part.0+0x488/0x510
[ 207.057195][T14945] ? page_table_check_clear.part.0+0x487/0x510
[ 207.058384][T14945] __page_table_check_pmd_clear+0x34b/0x5a0
[ 207.059524][T14945] ? __pfx___page_table_check_pmd_clear+0x10/0x10
[ 207.060775][T14945] ? __pfx___mutex_unlock_slowpath+0x10/0x10
[ 207.061940][T14945] ? __pfx___lock_acquire+0x10/0x10
[ 207.062967][T14945] pmdp_huge_clear_flush+0x279/0x360
[ 207.064024][T14945] split_huge_pmd_locked+0x82b/0x3750
...
Before commit 9cb28da546 ("mm/gup: handle hugetlb in the generic
follow_page_mask code"), we would have ignored the flag; instead, let's
simply refuse the combination completely in check_vma_flags(): the caller
is likely not prepared to handle any hugetlb folios.
We'll teach make_device_exclusive_range() separately to ignore any hugetlb
folios as a future-proof safety net.
Link: https://lkml.kernel.org/r/20250210193801.781278-1-david@redhat.com
Link: https://lkml.kernel.org/r/20250210193801.781278-2-david@redhat.com
Fixes: 9cb28da546 ("mm/gup: handle hugetlb in the generic follow_page_mask code")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Tested-by: Alistair Popple <apopple@nvidia.com>
Cc: Alex Shi <alexs@kernel.org>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Karol Herbst <kherbst@redhat.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Lyude <lyude@redhat.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yanteng Si <si.yanteng@linux.dev>
Cc: Simona Vetter <simona.vetter@ffwll.ch>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit dc84bc2aba ]
If track_pfn_copy() fails, we already added the dst VMA to the maple
tree. As fork() fails, we'll cleanup the maple tree, and stumble over
the dst VMA for which we neither performed any reservation nor copied
any page tables.
Consequently untrack_pfn() will see VM_PAT and try obtaining the
PAT information from the page table -- which fails because the page
table was not copied.
The easiest fix would be to simply clear the VM_PAT flag of the dst VMA
if track_pfn_copy() fails. However, the whole thing is about "simply"
clearing the VM_PAT flag is shaky as well: if we passed track_pfn_copy()
and performed a reservation, but copying the page tables fails, we'll
simply clear the VM_PAT flag, not properly undoing the reservation ...
which is also wrong.
So let's fix it properly: set the VM_PAT flag only if the reservation
succeeded (leaving it clear initially), and undo the reservation if
anything goes wrong while copying the page tables: clearing the VM_PAT
flag after undoing the reservation.
Note that any copied page table entries will get zapped when the VMA will
get removed later, after copy_page_range() succeeded; as VM_PAT is not set
then, we won't try cleaning VM_PAT up once more and untrack_pfn() will be
happy. Note that leaving these page tables in place without a reservation
is not a problem, as we are aborting fork(); this process will never run.
A reproducer can trigger this usually at the first try:
https://gitlab.com/davidhildenbrand/scratchspace/-/raw/main/reproducers/pat_fork.c
WARNING: CPU: 26 PID: 11650 at arch/x86/mm/pat/memtype.c:983 get_pat_info+0xf6/0x110
Modules linked in: ...
CPU: 26 UID: 0 PID: 11650 Comm: repro3 Not tainted 6.12.0-rc5+ #92
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-2.fc40 04/01/2014
RIP: 0010:get_pat_info+0xf6/0x110
...
Call Trace:
<TASK>
...
untrack_pfn+0x52/0x110
unmap_single_vma+0xa6/0xe0
unmap_vmas+0x105/0x1f0
exit_mmap+0xf6/0x460
__mmput+0x4b/0x120
copy_process+0x1bf6/0x2aa0
kernel_clone+0xab/0x440
__do_sys_clone+0x66/0x90
do_syscall_64+0x95/0x180
Likely this case was missed in:
d155df53f3 ("x86/mm/pat: clear VM_PAT if copy_p4d_range failed")
... and instead of undoing the reservation we simply cleared the VM_PAT flag.
Keep the documentation of these functions in include/linux/pgtable.h,
one place is more than sufficient -- we should clean that up for the other
functions like track_pfn_remap/untrack_pfn separately.
Fixes: d155df53f3 ("x86/mm/pat: clear VM_PAT if copy_p4d_range failed")
Fixes: 2ab640379a ("x86: PAT: hooks in generic vm code to help archs to track pfnmap regions - v3")
Reported-by: xingwei lee <xrivendell7@gmail.com>
Reported-by: yuxin wang <wang1315768607@163.com>
Reported-by: Marius Fleischer <fleischermarius@gmail.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org
Link: https://lore.kernel.org/r/20250321112323.153741-1-david@redhat.com
Closes: https://lore.kernel.org/lkml/CABOYnLx_dnqzpCW99G81DmOr+2UzdmZMk=T3uxwNxwz+R1RAwg@mail.gmail.com/
Closes: https://lore.kernel.org/lkml/CAJg=8jwijTP5fre8woS4JVJQ8iUA6v+iNcsOgtj9Zfpc3obDOQ@mail.gmail.com/
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit a1b65f3f7c ]
Turns out that this commit, about 10 years ago:
9ec23531fd ("sched/preempt, mm/fault: Trigger might_sleep() in might_fault() with disabled pagefaults")
... accidentally (and unnessecarily) put the lockdep part of
__might_fault() under CONFIG_DEBUG_ATOMIC_SLEEP=y.
This is potentially notable because large distributions such as
Ubuntu are running with !CONFIG_DEBUG_ATOMIC_SLEEP.
Restore the debug check.
[ mingo: Update changelog. ]
Fixes: 9ec23531fd ("sched/preempt, mm/fault: Trigger might_sleep() in might_fault() with disabled pagefaults")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: https://lore.kernel.org/r/20241104135517.536628371@infradead.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 14efb47935 upstream.
When an after-split folio is large and needs to be dropped due to EOF,
folio_put_refs(folio, folio_nr_pages(folio)) should be used to drop all
page cache refs. Otherwise, the folio will not be freed, causing memory
leak.
This leak would happen on a filesystem with blocksize > page_size and a
truncate is performed, where the blocksize makes folios split to >0 order
ones, causing truncated folios not being freed.
Link: https://lkml.kernel.org/r/20250310155727.472846-1-ziy@nvidia.com
Fixes: c010d47f10 ("mm: thp: split huge page to any lower order pages")
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reported-by: Hugh Dickins <hughd@google.com>
Closes: https://lore.kernel.org/all/fcbadb7f-dd3e-21df-f9a7-2853b53183c4@google.com/
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Kirill A. Shuemov <kirill.shutemov@linux.intel.com>
Cc: Luis Chamberalin <mcgrof@kernel.org>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <yang@os.amperecomputing.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9f01b49544 upstream.
Currently on cpu hotplug teardown, only memcg stock is drained but we
need to drain the obj stock as well otherwise we will miss the stats
accumulated on the target cpu as well as the nr_bytes cached. The stats
include MEMCG_KMEM, NR_SLAB_RECLAIMABLE_B & NR_SLAB_UNRECLAIMABLE_B. In
addition we are leaking reference to struct obj_cgroup object.
Link: https://lkml.kernel.org/r/20250310230934.2913113-1-shakeel.butt@linux.dev
Fixes: bf4f059954 ("mm: memcg/slab: obj_cgroup API")
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Yeoreum Yun