[ Upstream commit 4d5004451a ]
Fix a NULL deref crash that occurs when an svc_rqst is deferred
while the sunrpc tracing subsystem is enabled. svc_revisit() sets
dr->xprt to NULL, so it can't be relied upon in the tracepoint to
provide the remote's address.
Unfortunately we can't revert the "svc_deferred_class" hunk in
commit ece200ddd5 ("sunrpc: Save remote presentation address in
svc_xprt for trace events") because there is now a specific check
of event format specifiers for unsafe dereferences. The warning
that check emits is:
event svc_defer_recv has unsafe dereference of argument 1
A "%pISpc" format specifier with a "struct sockaddr *" is indeed
flagged by this check.
Instead, take the brute-force approach used by the svcrdma_qp_error
tracepoint. Convert the dr::addr field into a presentation address
in the TP_fast_assign() arm of the trace event, and store that as
a string. This fix can be backported to -stable kernels.
In the meantime, commit c6ced22997 ("tracing: Update print fmt
check to handle new __get_sockaddr() macro") is now in v5.18, so
this wonky fix can be replaced with __sockaddr() and friends
properly during the v5.19 merge window.
Fixes: ece200ddd5 ("sunrpc: Save remote presentation address in svc_xprt for trace events")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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