From: "wang, biao" <[email protected]>
Date: Fri, 3 May 2013 14:18:34 +0800
Subject: [PATCH] klist: del waiter from klist_remove_waiters before wakeup
waitting process
There is a race between klist_remove and klist_release. klist_remove
uses a local var waiter saved on stack. When klist_release calls
wake_up_process(waiter->process) to wake up the waiter, waiter might run
immediately and reuse the stack. Then, klist_release calls
list_del(&waiter->list) to change previous
wait data and cause prior waiter thread corrupt.
The patch fixes it against kernel 3.9.
Signed-off-by: wang, biao <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
---
lib/klist.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/lib/klist.c b/lib/klist.c
index 0874e41..358a368 100644
--- a/lib/klist.c
+++ b/lib/klist.c
@@ -193,10 +193,10 @@ static void klist_release(struct kref *kref)
if (waiter->node != n)
continue;
+ list_del(&waiter->list);
waiter->woken = 1;
mb();
wake_up_process(waiter->process);
- list_del(&waiter->list);
}
spin_unlock(&klist_remove_lock);
knode_set_klist(n, NULL);
--
1.7.6