Commit-ID: 72ef3794c5cd5f5f0e6355c24a529224c449cd14 Gitweb: http://git.kernel.org/tip/72ef3794c5cd5f5f0e6355c24a529224c449cd14 Author: Steven Rostedt <[email protected]> AuthorDate: Tue, 5 Jun 2012 19:28:14 +0900 Committer: Steven Rostedt <[email protected]> CommitDate: Tue, 31 Jul 2012 10:29:55 -0400
kprobes: Inverse taking of module_mutex with kprobe_mutex Currently module_mutex is taken before kprobe_mutex, but this can cause issues when we have kprobes register ftrace, as the ftrace mutex is taken before enabling a tracepoint, which currently takes the module mutex. If module_mutex is taken before kprobe_mutex, then we can not have kprobes use the ftrace infrastructure. There seems to be no reason that the kprobe_mutex can't be taken before the module_mutex. Running lockdep shows that it is safe among the kernels I've run. Link: http://lkml.kernel.org/r/[email protected] Cc: Thomas Gleixner <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Ananth N Mavinakayanahalli <[email protected]> Cc: "Frank Ch. Eigler" <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Frederic Weisbecker <[email protected]> Cc: Masami Hiramatsu <[email protected]> Signed-off-by: Steven Rostedt <[email protected]> --- kernel/kprobes.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/kprobes.c b/kernel/kprobes.c index c62b854..7a8a122 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -561,9 +561,9 @@ static __kprobes void kprobe_optimizer(struct work_struct *work) { LIST_HEAD(free_list); + mutex_lock(&kprobe_mutex); /* Lock modules while optimizing kprobes */ mutex_lock(&module_mutex); - mutex_lock(&kprobe_mutex); /* * Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed) @@ -586,8 +586,8 @@ static __kprobes void kprobe_optimizer(struct work_struct *work) /* Step 4: Free cleaned kprobes after quiesence period */ do_free_cleaned_kprobes(&free_list); - mutex_unlock(&kprobe_mutex); mutex_unlock(&module_mutex); + mutex_unlock(&kprobe_mutex); /* Step 5: Kick optimizer again if needed */ if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
