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RDMA/rxe: Fix seg fault in rxe_comp_queue_pkt

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[ Upstream commit 2b23b6097303ed0ba5f4bc036a1c07b6027af5c6 ]

In rxe_comp_queue_pkt() an incoming response packet skb is enqueued to the
resp_pkts queue and then a decision is made whether to run the completer
task inline or schedule it. Finally the skb is dereferenced to bump a 'hw'
performance counter. This is wrong because if the completer task is
already running in a separate thread it may have already processed the skb
and freed it which can cause a seg fault.  This has been observed
infrequently in testing at high scale.

This patch fixes this by changing the order of enqueuing the packet until
after the counter is accessed.

Link: https://lore.kernel.org/r/20240329145513.35381-4-rpearsonhpe@gmail.com
Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
Fixes: 0b1e5b99a48b ("IB/rxe: Add port protocol stats")
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Bob Pearson 2024-03-29 09:55:04 -05:00 committed by Greg Kroah-Hartman
parent 63cbb3e704
commit 21b4c6d4d8
1 changed files with 3 additions and 3 deletions
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6
drivers/infiniband/sw/rxe/rxe_comp.c
View File

@ -131,12 +131,12 @@ void rxe_comp_queue_pkt(struct rxe_qp *qp, struct sk_buff *skb)
{
int must_sched;
skb_queue_tail(&qp->resp_pkts, skb);
must_sched = skb_queue_len(&qp->resp_pkts) > 1;
must_sched = skb_queue_len(&qp->resp_pkts) > 0;
if (must_sched != 0)
rxe_counter_inc(SKB_TO_PKT(skb)->rxe, RXE_CNT_COMPLETER_SCHED);
skb_queue_tail(&qp->resp_pkts, skb);
if (must_sched)
rxe_sched_task(&qp->comp.task);
else