linux/include/trace
Chuck Lever 726ae7300f SUNRPC: Fix the svc_deferred_event trace class
[ 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>
2022-04-20 09:34:09 +02:00
..
events SUNRPC: Fix the svc_deferred_event trace class 2022-04-20 09:34:09 +02:00
bpf_probe.h trace: bpf: Allow bpf to attach to bare tracepoints 2021-01-20 14:13:59 -08:00
define_trace.h tracepoint: Optimize using static_call() 2020-09-01 09:58:06 +02:00
perf.h
syscall.h tracepoints: Migrate to use SYSCALL_WORK flag 2020-11-16 21:53:15 +01:00
trace_events.h tracing: Add trace_event helper macros __string_len() and __assign_str_len() 2021-08-17 11:47:52 -04:00