kprobes: Fix a double lock bug of kprobe_mutex

Fix a double locking bug caused when debug.kprobe-optimization=0.
While the proc_kprobes_optimization_handler locks kprobe_mutex,
wait_for_kprobe_optimizer locks it again and that causes a double lock.
To fix the bug, this introduces different mutex for protecting
sysctl parameter and locks it in proc_kprobes_optimization_handler.
Of course, since we need to lock kprobe_mutex when touching kprobes
resources, that is done in *optimize_all_kprobes().

This bug was introduced by commit ad72b3bea744 ("kprobes: fix

Signed-off-by: Masami Hiramatsu <>
Acked-by: Ananth N Mavinakayanahalli <>
Cc: Ingo Molnar <>
Cc: Tejun Heo <>
Cc: "David S. Miller" <>
Signed-off-by: Linus Torvalds <>
1 file changed