| From | Kamal Mostafa <> | Subject | [PATCH 032/105] klist: del waiter from klist_remove_waiters before wakeup waitting process | Date | Fri, 28 Jun 2013 11:50:54 -0700 |
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3.8.13.4 -stable review patch. If anyone has any objections, please let me know.
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From: "wang, biao" <biao.wang@intel.com>
commit ac5a2962b02f57dea76d314ef2521a2170b28ab6 upstream.
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 <biao.wang@intel.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- lib/klist.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
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); -- 1.8.1.2
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