The patch titled
freezer: read PF_BORROWED_MM in a nonracy way
has been added to the -mm tree. Its filename is
freezer-read-pf_borrowed_mm-in-a-nonracy-way.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: freezer: read PF_BORROWED_MM in a nonracy way
From: Rafael J. Wysocki <rjw@xxxxxxx>
The reading of PF_BORROWED_MM in is_user_space() without task_lock() is racy.
Fix it.
Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
Acked-by: Pavel Machek <pavel@xxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Aneesh Kumar <aneesh.kumar@xxxxxxxxx>
Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Srivatsa Vaddagiri <vatsa@xxxxxxxxxx>
Cc: Gautham R Shenoy <ego@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/power/process.c | 8 +++++++-
1 files changed, 7 insertions(+), 1 deletion(-)
diff -puN kernel/power/process.c~freezer-read-pf_borrowed_mm-in-a-nonracy-way kernel/power/process.c
--- a/kernel/power/process.c~freezer-read-pf_borrowed_mm-in-a-nonracy-way
+++ a/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>
@@ -89,7 +90,12 @@ 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)
_
Patches currently in -mm which might be from rjw@xxxxxxx are
make-xfs-workqueues-nonfreezable.patch
fix-refrigerator-vs-thaw_process-race.patch
freezer-task-exit_state-should-be-treated-as-bolean.patch
documentation-ask-driver-writers-to-provide-pm-support.patch
freezer-read-pf_borrowed_mm-in-a-nonracy-way.patch
freezer-close-theoretical-race-between-refrigerator-and-thaw_tasks.patch
freezer-remove-pf_nofreeze-from-rcutorture-thread.patch
freezer-remove-pf_nofreeze-from-bluetooth-threads.patch
freezer-add-try_to_freeze-calls-to-all-kernel-threads.patch
freezer-fix-vfork-problem.patch
freezer-take-kernel_execve-into-consideration.patch
shrink_slab-handle-bad-shrinkers.patch
-
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