Patchwork [3.11.y.z,extended,stable] Patch "trace: module: Maintain a valid user count" has been added to staging queue

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Submitter Luis Henriques
Date May 14, 2014, 2:57 p.m.
Message ID <1400079472-16751-1-git-send-email-luis.henriques@canonical.com>
Download mbox | patch
Permalink /patch/348830/
State New
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Luis Henriques - May 14, 2014, 2:57 p.m.
This is a note to let you know that I have just added a patch titled

    trace: module: Maintain a valid user count

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

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From 2781c249977344e46c2e66ab8d4ad6f9c643de54 Mon Sep 17 00:00:00 2001
From: Romain Izard <romain.izard.pro@gmail.com>
Date: Tue, 4 Mar 2014 10:09:39 +0100
Subject: trace: module: Maintain a valid user count

commit 098507ae3ec2331476fb52e85d4040c1cc6d0ef4 upstream.

The replacement of the 'count' variable by two variables 'incs' and
'decs' to resolve some race conditions during module unloading was done
in parallel with some cleanup in the trace subsystem, and was integrated
as a merge.

Unfortunately, the formula for this replacement was wrong in the tracing
code, and the refcount in the traces was not usable as a result.

Use 'count = incs - decs' to compute the user count.

Link: http://lkml.kernel.org/p/1393924179-9147-1-git-send-email-romain.izard.pro@gmail.com

Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Fixes: c1ab9cab7509 "merge conflict resolution"
Signed-off-by: Romain Izard <romain.izard.pro@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
 include/trace/events/module.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--
1.9.1

Patch

diff --git a/include/trace/events/module.h b/include/trace/events/module.h
index 1619327..ca298c7 100644
--- a/include/trace/events/module.h
+++ b/include/trace/events/module.h
@@ -78,7 +78,7 @@  DECLARE_EVENT_CLASS(module_refcnt,

 	TP_fast_assign(
 		__entry->ip	= ip;
-		__entry->refcnt	= __this_cpu_read(mod->refptr->incs) + __this_cpu_read(mod->refptr->decs);
+		__entry->refcnt	= __this_cpu_read(mod->refptr->incs) - __this_cpu_read(mod->refptr->decs);
 		__assign_str(name, mod->name);
 	),