linux-kernel - [PATCH 1/7] Freezer: Read PF_BORROWED

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: <200705110036.26617.rjw@sisk.pl>
Date:	Fri, 11 May 2007 00:36:25 +0200
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Gautham R Shenoy <ego@...ibm.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Oleg Nesterov <oleg@...sign.ru>, Pavel Machek <pavel@....cz>,
	"Eric W. Biederman" <ebiederm@...ssion.com>
Subject: [PATCH 1/7] Freezer: Read PF_BORROWED_MM in a nonracy way

From: Rafael J. Wysocki <rjw@...k.pl>

The reading of PF_BORROWED_MM in is_user_space() without task_lock() is racy. 
Fix it.

Signed-off-by: Rafael J. Wysocki <rjw@...k.pl>
Acked-by: Pavel Machek <pavel@....cz>
---
 kernel/power/process.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

Index: linux-2.6/kernel/power/process.c
===================================================================
--- linux-2.6.orig/kernel/power/process.c	2007-05-10 21:44:23.000000000 +0200
+++ linux-2.6/kernel/power/process.c	2007-05-10 21:44:28.000000000 +0200
@@ -8,6 +8,7 @@
 
 #undef DEBUG
 
+#include <linux/sched.h>
 #include <linux/interrupt.h>
 #include <linux/suspend.h>
 #include <linux/module.h>
@@ -88,7 +89,12 @@ static void cancel_freezing(struct task_
 
 static inline int is_user_space(struct task_struct *p)
 {
-	return p->mm && !(p->flags & PF_BORROWED_MM);
+	int ret;
+
+	task_lock(p);
+	ret = p->mm && !(p->flags & PF_BORROWED_MM);
+	task_unlock(p);
+	return ret;
 }
 
 static unsigned int try_to_freeze_tasks(int freeze_user_space)

-
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/