Commit 0be05c4b authored Jun 27, 2024 by Bob Pearson Committed by Liu Jian Jun 27, 2024

RDMA/rxe: Fix seg fault in rxe_comp_queue_pkt

stable inclusion
from stable-v6.6.33
commit 21b4c6d4d89030fd4657a8e7c8110fd941049794
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IA72Y8
CVE: CVE-2024-38544

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=21b4c6d4d89030fd4657a8e7c8110fd941049794

---------------------------

[ 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: 0b1e5b99 ("IB/rxe: Add port protocol stats")
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Liu Jian <liujian56@huawei.com>

parent 43499e79

drivers/infiniband/sw/rxe/rxe_comp.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -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