The patch titled
sys_getppid oopses on debug kernel
has been added to the -mm tree. Its filename is
sys_getppid-oopses-on-debug-kernel-v2.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: sys_getppid oopses on debug kernel
From: Kirill Korotaev <dev@xxxxx>
sys_getppid() optimization can access a freed memory. On kernels with
DEBUG_SLAB turned ON, this results in Oops. As Dave Hansen noted, this
optimization is also unsafe for memory hotplug.
So this patch always takes the lock to be safe.
Signed-off-by: Kirill Korotaev <dev@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxx>
Cc: Dave Hansen <haveblue@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
kernel/timer.c | 23 +++--------------------
1 files changed, 3 insertions(+), 20 deletions(-)
diff -puN kernel/timer.c~sys_getppid-oopses-on-debug-kernel-v2 kernel/timer.c
--- a/kernel/timer.c~sys_getppid-oopses-on-debug-kernel-v2
+++ a/kernel/timer.c
@@ -1342,28 +1342,11 @@ asmlinkage long sys_getpid(void)
asmlinkage long sys_getppid(void)
{
int pid;
- struct task_struct *me = current;
- struct task_struct *parent;
- parent = me->group_leader->real_parent;
- for (;;) {
- pid = parent->tgid;
-#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
-{
- struct task_struct *old = parent;
+ read_lock(&tasklist_lock);
+ pid = current->group_leader->real_parent->tgid;
+ read_unlock(&tasklist_lock);
- /*
- * Make sure we read the pid before re-reading the
- * parent pointer:
- */
- smp_rmb();
- parent = me->group_leader->real_parent;
- if (old != parent)
- continue;
-}
-#endif
- break;
- }
return pid;
}
_
Patches currently in -mm which might be from dev@xxxxx are
sys_getppid-oopses-on-debug-kernel-v2.patch
fix-unserialized-task-files-changing.patch
ipc-namespace-utils.patch
-
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