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| author | Chuck Lever <chuck.lever@oracle.com> | 2022-04-06 13:51:32 -0400 |
|---|---|---|
| committer | Chuck Lever <chuck.lever@oracle.com> | 2022-04-07 10:22:51 -0400 |
| commit | 4d5004451ab2218eab94a30e1841462c9316ba19 (patch) | |
| tree | ebc22ea61cad0ed0384e6ee9d818f47754d89e6a /include | |
| parent | 773f91b2cf3f52df0d7508fdbf60f37567cdaee4 (diff) | |
| download | linux-4d5004451ab2218eab94a30e1841462c9316ba19.tar.bz2 | |
SUNRPC: Fix the svc_deferred_event trace class
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 ece200ddd54b ("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 c6ced22997ad ("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: ece200ddd54b ("sunrpc: Save remote presentation address in svc_xprt for trace events")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/trace/events/sunrpc.h | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h index ab8ae1f6ba84..4eb706fa5825 100644 --- a/include/trace/events/sunrpc.h +++ b/include/trace/events/sunrpc.h @@ -2017,17 +2017,18 @@ DECLARE_EVENT_CLASS(svc_deferred_event, TP_STRUCT__entry( __field(const void *, dr) __field(u32, xid) - __string(addr, dr->xprt->xpt_remotebuf) + __array(__u8, addr, INET6_ADDRSTRLEN + 10) ), TP_fast_assign( __entry->dr = dr; __entry->xid = be32_to_cpu(*(__be32 *)(dr->args + (dr->xprt_hlen>>2))); - __assign_str(addr, dr->xprt->xpt_remotebuf); + snprintf(__entry->addr, sizeof(__entry->addr) - 1, + "%pISpc", (struct sockaddr *)&dr->addr); ), - TP_printk("addr=%s dr=%p xid=0x%08x", __get_str(addr), __entry->dr, + TP_printk("addr=%s dr=%p xid=0x%08x", __entry->addr, __entry->dr, __entry->xid) ); |