RDMA/rxe: Fix seg fault in rxe_comp_queue_pkt

commit 2b23b609 upstream.

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>
[Sherry: bp to fix CVE-2024-38544. Fix conflict due to missing commit:
dccb23f6 ("RDMA/rxe: Split rxe_run_task() into two subroutines")
which is not necessary to backport]
Signed-off-by: Sherry Yang <sherry.yang@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>