[PATCH] [Natty SRU] UBUNTU: SAUCE: fix yama_ptracer_del lockdep warning

[Ming Lei]

From 7e597da6c9b6aea298ac8fdf93951a4d4b259d68 Mon Sep 17 00:00:00 2001
From: Ming Lei <ming.lei at canonical.com>
Date: Wed, 29 Jun 2011 19:06:25 +0800
Subject: [PATCH] [Natty SRU] UBUNTU: SAUCE: fix yama_ptracer_del lockdep warning

yama_ptracer_del can be called in softirq context, also
can be run in common process context, so take spin_lock_bh
in yama_ptracer_del to fix it, othewise deadlock may be
produced.

SRU Justification:

Impact:
	- lockdep warning is triggered if lockdep config options are
	  enabled
	- probably deadlock can be produced in yama_ptracer_del path

Fix:
	- After applying the patch, lockdep warning is fixefd

BugLink: http://bugs.launchpad.net/bugs/791019

Signed-off-by: Ming Lei <ming.lei at canonical.com>
---
 security/yama/yama_lsm.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/security/yama/yama_lsm.c b/security/yama/yama_lsm.c
index 7c3591a..927e6ad 100644
--- a/security/yama/yama_lsm.c
+++ b/security/yama/yama_lsm.c
@@ -82,7 +82,7 @@ static void yama_ptracer_del(struct task_struct *tracer,
 	struct ptrace_relation *relation;
 	struct list_head *list, *safe;
 
-	spin_lock(&ptracer_relations_lock);
+	spin_lock_bh(&ptracer_relations_lock);
 	list_for_each_safe(list, safe, &ptracer_relations) {
 		relation = list_entry(list, struct ptrace_relation, node);
 		if (relation->tracee == tracee ||
@@ -91,7 +91,7 @@ static void yama_ptracer_del(struct task_struct *tracer,
 			kfree(relation);
 		}
 	}
-	spin_unlock(&ptracer_relations_lock);
+	spin_unlock_bh(&ptracer_relations_lock);
 }
 
 /**
-- 
1.7.4.1



--
Ming Lei