From: Rafael J. Wysocki <[EMAIL PROTECTED]>
The reading of PF_BORROWED_MM in is_user_space() without task_lock() is racy.
Fix it.
Signed-off-by: Rafael J. Wysocki <[EMAIL PROTECTED]>
Acked-by: Pavel Machek <[EMAIL PROTECTED]>
---
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)
-
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