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authorGleb Natapov <gleb@redhat.com>2011-10-18 19:55:51 +0200
committerSteven Rostedt <rostedt@goodmis.org>2011-11-07 11:02:34 -0500
commitc8452afb7426f7e21388492f40227582e3e83879 (patch)
treedd01f094321d9d8c6412d11cc4dd1a33d18b48f7 /kernel/jump_label.c
parent8ee3c92b7f2751c392be2d8fc360a410480b8757 (diff)
downloadlinux-sh-c8452afb7426f7e21388492f40227582e3e83879.tar.gz
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 <a.p.zijlstra@chello.nl> Acked-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/jump_label.c')
-rw-r--r--kernel/jump_label.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index a8ce45097f3d..e6f1f24ad577 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();
}