Messages in this thread Patch in this message | | | Date | Tue, 18 Oct 2011 19:55:51 +0200 | From | Gleb Natapov <> | Subject | [PATCH] jump_label_inc may return before the code is patched |
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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.
Signed-off-by: Gleb Natapov <gleb@redhat.com> 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(); } -- Gleb.
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