linux-kernel - [PATCH 19/17] freezer: use lock_task_sighand() in fake_signal_wake

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]

Message-ID: <20111031223526.GE18855@google.com>
Date:	Mon, 31 Oct 2011 15:35:26 -0700
From:	Tejun Heo <tj@...nel.org>
To:	rjw@...k.pl, paul@...lmenage.org, linux-kernel@...r.kernel.org,
	linux-pm@...r.kernel.org
Cc:	arnd@...db.de, oleg@...hat.com, matthltc@...ibm.com
Subject: [PATCH 19/17] freezer: use lock_task_sighand() in
 fake_signal_wake_up()

cgroup_freezer calls freeze_task() without holding tasklist_lock and,
if the task is exiting, its ->sighand may be gone by the time
fake_signal_wake_up() is called.  Use lock_task_sighand() instead of
accessing ->sighand directly.

Signed-off-by: Tejun Heo <tj@...nel.org>
Reported-by: Oleg Nesterov <oleg@...hat.com>
Acked-by: Oleg Nesterov <oleg@...hat.com>
Cc: "Rafael J. Wysocki" <rjw@...k.pl>
Cc: Paul Menage <paul@...lmenage.org>
---
 kernel/freezer.c |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/freezer.c b/kernel/freezer.c
index 10f9840..a9c18c7 100644
--- a/kernel/freezer.c
+++ b/kernel/freezer.c
@@ -93,9 +93,10 @@ static void fake_signal_wake_up(struct task_struct *p)
 {
 	unsigned long flags;
 
-	spin_lock_irqsave(&p->sighand->siglock, flags);
-	signal_wake_up(p, 1);
-	spin_unlock_irqrestore(&p->sighand->siglock, flags);
+	if (lock_task_sighand(p, &flags)) {
+		signal_wake_up(p, 1);
+		unlock_task_sighand(p, &flags);
+	}
 }
 
 /**
-- 
1.7.3.1

--
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/