From: Gleb Natapov Date: Tue, 18 Oct 2011 17:55:51 +0000 (+0200) Subject: jump_label: jump_label_inc may return before the code is patched X-Git-Tag: v3.3-rc1~51^2~97^2~3 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=c8452afb7426f7e21388492f40227582e3e83879;p=profile%2Fivi%2Fkernel-adaptation-intel-automotive.git jump_label: jump_label_inc may return before the code is patched If cpu A calls jump_label_inc() just after atomic_add_return() is called by cpu B, atomic_inc_not_zero() will return value greater then zero and jump_label_inc() will return to a caller before jump_label_update() finishes its job on cpu B. Link: http://lkml.kernel.org/r/20111018175551.GH17571@redhat.com Cc: stable@vger.kernel.org Cc: Peter Zijlstra Acked-by: Jason Baron Signed-off-by: Gleb Natapov Signed-off-by: Steven Rostedt --- diff --git a/kernel/jump_label.c b/kernel/jump_label.c index a8ce450..e6f1f24 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -66,8 +66,9 @@ void jump_label_inc(struct jump_label_key *key) return; jump_label_lock(); - if (atomic_add_return(1, &key->enabled) == 1) + if (atomic_read(&key->enabled) == 0) jump_label_update(key, JUMP_LABEL_ENABLE); + atomic_inc(&key->enabled); jump_label_unlock(); }