linux-kernel - [PATCH v2] trace: module: Maintain a valid user count

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue,  4 Mar 2014 10:09:39 +0100
From:	Romain Izard <romain.izard.pro@...il.com>
To:	Steven Rostedt <rostedt@...dmis.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org
Cc:	Romain Izard <romain.izard.pro@...il.com>
Subject: [PATCH v2] trace: module: Maintain a valid user count

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.

Signed-off-by: Romain Izard <romain.izard.pro@...il.com>
---
 include/trace/events/module.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/trace/events/module.h b/include/trace/events/module.h
index 161932737416..ca298c7157ae 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);
 	),
 
-- 
1.8.3.2

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/