Messages in this thread Patch in this message | | | From | "Rafael J. Wysocki" <> | Subject | [RFC][PATCH 1/7] Freezer: Read PF_BORROWED_MM in a nonracy way | Date | Fri, 23 Feb 2007 11:18:06 +0100 |
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From: Rafael J. Wysocki <rjw@sisk.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@sisk.pl> --- kernel/power/process.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
Index: linux-2.6.20-mm2/kernel/power/process.c =================================================================== --- linux-2.6.20-mm2.orig/kernel/power/process.c +++ linux-2.6.20-mm2/kernel/power/process.c @@ -8,6 +8,7 @@ #undef DEBUG +#include <linux/sched.h> #include <linux/smp_lock.h> #include <linux/interrupt.h> #include <linux/suspend.h> @@ -92,7 +93,12 @@ 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@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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