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Patch "net: sunrpc: fix tracepoint Warning: unknown op '->'" has been added to the 4.2-stable tree

PATCH [email protected] 1 participant 1 message Sep 26, 2015

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This is a note to let you know that I've just added the patch titled

    net: sunrpc: fix tracepoint Warning: unknown op '->'

to the 4.2-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
net-sunrpc-fix-tracepoint-warning-unknown-op.patch
and it can be found in the queue-4.2 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From 051ac3848a94f21cfdec899cc9c65ce7f9f116fa Mon Sep 17 00:00:00 2001

From: Pratyush Anand <[email protected]>
Date: Thu, 27 Aug 2015 10:01:33 +0530
Subject: net: sunrpc: fix tracepoint Warning: unknown op '->'

From: Pratyush Anand <[email protected]>

commit 051ac3848a94f21cfdec899cc9c65ce7f9f116fa upstream.

perf stat -e sunrpc:svc_xprt_do_enqueue true results in

Warning: unknown op '->'
Warning: [sunrpc:svc_xprt_do_enqueue] unknown op '->'

Similar warning for svc_handle_xprt as well.

Actually TP_printk() should never dereference an address saved in the ring buffer that points somewhere in the kernel. There's no guarantee that that object still exists (with the exception of static strings).

Therefore change all the arguments for TP_printk(), so that it references values existing in the ring buffer only.

While doing that, also fix another possible bug when argument xprt could be NULL and TP_fast_assign() tries to access it's elements.

Signed-off-by Pratyush Anand <[email protected]>
Reviewed-by Jeff Layton <[email protected]>
Acked-by Steven Rostedt <[email protected]>
Fixes 83a712e0afef "sunrpc: add some tracepoints around ..."
Signed-off-by J. Bruce Fields <[email protected]>
Signed-off-by Greg Kroah-Hartman <[email protected]>
---
 include/trace/events/sunrpc.h |   21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)
include/trace/events/sunrpc.h +14 -7
@@ -529,18 +529,21 @@ TRACE_EVENT(svc_xprt_do_enqueue,
 
 	TP_STRUCT__entry(
 		__field(struct svc_xprt *, xprt)
-		__field(struct svc_rqst *, rqst)
+		__field_struct(struct sockaddr_storage, ss)
+		__field(int, pid)
+		__field(unsigned long, flags)
 	),
 
 	TP_fast_assign(
 		__entry->xprt = xprt;
-		__entry->rqst = rqst;
+		xprt ? memcpy(&__entry->ss, &xprt->xpt_remote, sizeof(__entry->ss)) : memset(&__entry->ss, 0, sizeof(__entry->ss));
+		__entry->pid = rqst? rqst->rq_task->pid : 0;
+		__entry->flags = xprt ? xprt->xpt_flags : 0;
 	),
 
 	TP_printk("xprt=0x%p addr=%pIScp pid=%d flags=%s", __entry->xprt,
-		(struct sockaddr *)&__entry->xprt->xpt_remote,
-		__entry->rqst ? __entry->rqst->rq_task->pid : 0,
-		show_svc_xprt_flags(__entry->xprt->xpt_flags))
+		(struct sockaddr *)&__entry->ss,
+		__entry->pid, show_svc_xprt_flags(__entry->flags))
 );
 
 TRACE_EVENT(svc_xprt_dequeue,

@@ -589,16 +592,20 @@ TRACE_EVENT(svc_handle_xprt,
 	TP_STRUCT__entry(
 		__field(struct svc_xprt *, xprt)
 		__field(int, len)
+		__field_struct(struct sockaddr_storage, ss)
+		__field(unsigned long, flags)
 	),
 
 	TP_fast_assign(
 		__entry->xprt = xprt;
+		xprt ? memcpy(&__entry->ss, &xprt->xpt_remote, sizeof(__entry->ss)) : memset(&__entry->ss, 0, sizeof(__entry->ss));
 		__entry->len = len;
+		__entry->flags = xprt ? xprt->xpt_flags : 0;
 	),
 
 	TP_printk("xprt=0x%p addr=%pIScp len=%d flags=%s", __entry->xprt,
-		(struct sockaddr *)&__entry->xprt->xpt_remote, __entry->len,
-		show_svc_xprt_flags(__entry->xprt->xpt_flags))
+		(struct sockaddr *)&__entry->ss,
+		__entry->len, show_svc_xprt_flags(__entry->flags))
 );
 #endif /* _TRACE_SUNRPC_H */

Patches currently in stable-queue which might be from [email protected] are

queue-4.2/net-sunrpc-fix-tracepoint-warning-unknown-op.patch