David Howells 12a072a0b7 afs: Fix race in async call refcounting ... [ Upstream commit 34fa47612b ] There's a race between afs_make_call() and afs_wake_up_async_call() in the case that an error is returned from rxrpc_kernel_send_data() after it has queued the final packet. afs_make_call() will try and clean up the mess, but the call state may have been moved on thereby causing afs_process_async_call() to also try and to delete the call. Fix this by: (1) Getting an extra ref for an asynchronous call for the call itself to hold. This makes sure the call doesn't evaporate on us accidentally and will allow the call to be retained by the caller in a future patch. The ref is released on leaving afs_make_call() or afs_wait_for_call_to_complete(). (2) In the event of an error from rxrpc_kernel_send_data(): (a) Don't set the call state to AFS_CALL_COMPLETE until *after* the call has been aborted and ended. This prevents afs_deliver_to_call() from doing anything with any notifications it gets. (b) Explicitly end the call immediately to prevent further callbacks. (c) Cancel any queued async_work and wait for the work if it's executing. This allows us to be sure the race won't recur when we change the state. We put the work queue's ref on the call if we managed to cancel it. (d) Put the call's ref that we got in (1). This belongs to us as long as the call is in state AFS_CALL_CL_REQUESTING. Fixes: 341f741f04 ("afs: Refcount the afs_call struct") Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>		2019-02-27 10:09:50 +01:00
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events	afs: Fix race in async call refcounting	2019-02-27 10:09:50 +01:00
bpf_probe.h	bpf: introduce BPF_RAW_TRACEPOINT	2018-03-28 22:55:19 +02:00
define_trace.h	bpf: introduce BPF_RAW_TRACEPOINT	2018-03-28 22:55:19 +02:00
perf.h	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2017-11-04 09:26:51 +09:00
syscall.h	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
trace_events.h	tracing: Prevent further users of zero size static arrays in trace events	2018-05-29 08:29:13 -04:00