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net: ps3_gelic_net: handle skb allocation failures

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Handle skb allocation failures in RX path, to avoid NULL pointer
dereference and RX stalls under memory pressure. If the refill fails
with -ENOMEM, complete napi polling and wake up later to retry via timer.
Also explicitly re-enable RX DMA after oom, so the dmac doesn't remain
stopped in this situation.

Previously, memory pressure could lead to skb allocation failures and
subsequent Oops like:

	Oops: Kernel access of bad area, sig: 11 [#2]
	Hardware name: SonyPS3 Cell Broadband Engine 0x701000 PS3
	NIP [c0003d0000065900] gelic_net_poll+0x6c/0x2d0 [ps3_gelic] (unreliable)
	LR [c0003d00000659c4] gelic_net_poll+0x130/0x2d0 [ps3_gelic]
	Call Trace:
	  gelic_net_poll+0x130/0x2d0 [ps3_gelic] (unreliable)
	  __napi_poll+0x44/0x168
	  net_rx_action+0x178/0x290

Steps to reproduce the issue:
	1. Start a continuous network traffic, like scp of a 20GB file
	2. Inject failslab errors using the kernel fault injection:
	    echo -1 > /sys/kernel/debug/failslab/times
	    echo 30 > /sys/kernel/debug/failslab/interval
	    echo 100 > /sys/kernel/debug/failslab/probability
	3. After some time, traces start to appear, kernel Oopses
	   and the system stops

Step 2 is not always necessary, as it is usually already triggered by
the transfer of a big enough file.

Fixes: 02c1889166 ("ps3: gigabit ethernet driver for PS3, take3")
Signed-off-by: Florian Fuchs <fuchsfl@gmail.com>
Link: https://patch.msgid.link/20251113181000.3914980-1-fuchsfl@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Florian Fuchs 2025-11-13 19:10:00 +01:00 committed by Paolo Abeni
parent 896f1a2493
commit 0f08f0b0fb
2 changed files with 35 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

45
drivers/net/ethernet/toshiba/ps3_gelic_net.c
View File

@ -260,6 +260,7 @@ void gelic_card_down(struct gelic_card *card)
if (atomic_dec_if_positive(&card->users) == 0) {
pr_debug("%s: real do\n", __func__);
napi_disable(&card->napi);
timer_delete_sync(&card->rx_oom_timer);
/*
* Disable irq. Wireless interrupts will
* be disabled later if any
@ -970,7 +971,8 @@ static void gelic_net_pass_skb_up(struct gelic_descr *descr,
* gelic_card_decode_one_descr - processes an rx descriptor
* @card: card structure
*
* returns 1 if a packet has been sent to the stack, otherwise 0
* returns 1 if a packet has been sent to the stack, -ENOMEM on skb alloc
* failure, otherwise 0
*
* processes an rx descriptor by iommu-unmapping the data buffer and passing
* the packet up to the stack
@ -981,16 +983,18 @@ static int gelic_card_decode_one_descr(struct gelic_card *card)
struct gelic_descr_chain *chain = &card->rx_chain;
struct gelic_descr *descr = chain->head;
struct net_device *netdev = NULL;
int dmac_chain_ended;
int dmac_chain_ended = 0;
int prepare_rx_ret;
status = gelic_descr_get_status(descr);
if (status == GELIC_DESCR_DMA_CARDOWNED)
return 0;
if (status == GELIC_DESCR_DMA_NOT_IN_USE) {
if (status == GELIC_DESCR_DMA_NOT_IN_USE || !descr->skb) {
dev_dbg(ctodev(card), "dormant descr? %p\n", descr);
return 0;
dmac_chain_ended = 1;
goto refill;
}
/* netdevice select */
@ -1048,9 +1052,10 @@ static int gelic_card_decode_one_descr(struct gelic_card *card)
refill:
/* is the current descriptor terminated with next_descr == NULL? */
dmac_chain_ended =
be32_to_cpu(descr->hw_regs.dmac_cmd_status) &
GELIC_DESCR_RX_DMA_CHAIN_END;
if (!dmac_chain_ended)
dmac_chain_ended =
be32_to_cpu(descr->hw_regs.dmac_cmd_status) &
GELIC_DESCR_RX_DMA_CHAIN_END;
/*
* So that always DMAC can see the end
* of the descriptor chain to avoid
@ -1062,10 +1067,11 @@ refill:
gelic_descr_set_status(descr, GELIC_DESCR_DMA_NOT_IN_USE);
/*
* this call can fail, but for now, just leave this
* descriptor without skb
* this call can fail, propagate the error
*/
gelic_descr_prepare_rx(card, descr);
prepare_rx_ret = gelic_descr_prepare_rx(card, descr);
if (prepare_rx_ret)
return prepare_rx_ret;
chain->tail = descr;
chain->head = descr->next;
@ -1087,6 +1093,13 @@ refill:
return 1;
}
static void gelic_rx_oom_timer(struct timer_list *t)
{
struct gelic_card *card = timer_container_of(card, t, rx_oom_timer);
napi_schedule(&card->napi);
}
/**
* gelic_net_poll - NAPI poll function called by the stack to return packets
* @napi: napi structure
@ -1099,14 +1112,22 @@ static int gelic_net_poll(struct napi_struct *napi, int budget)
{
struct gelic_card *card = container_of(napi, struct gelic_card, napi);
int packets_done = 0;
int work_result = 0;
while (packets_done < budget) {
if (!gelic_card_decode_one_descr(card))
work_result = gelic_card_decode_one_descr(card);
if (work_result != 1)
break;
packets_done++;
}
if (work_result == -ENOMEM) {
napi_complete_done(napi, packets_done);
mod_timer(&card->rx_oom_timer, jiffies + 1);
return packets_done;
}
if (packets_done < budget) {
napi_complete_done(napi, packets_done);
gelic_card_rx_irq_on(card);
@ -1576,6 +1597,8 @@ static struct gelic_card *gelic_alloc_card_net(struct net_device **netdev)
mutex_init(&card->updown_lock);
atomic_set(&card->users, 0);
timer_setup(&card->rx_oom_timer, gelic_rx_oom_timer, 0);
return card;
}

1
drivers/net/ethernet/toshiba/ps3_gelic_net.h
View File

@ -268,6 +268,7 @@ struct gelic_vlan_id {
struct gelic_card {
struct napi_struct napi;
struct net_device *netdev[GELIC_PORT_MAX];
struct timer_list rx_oom_timer;
/*
* hypervisor requires irq_status should be
* 8 bytes aligned, but u64 member is