diff options
| author | Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> | 2013-07-09 18:35:26 +0900 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-08-29 09:47:32 -0700 |
| commit | e899e7e4f83ecd606e85d355410d724ec76542cb (patch) | |
| tree | eca9720c6879e4726969b1e597271c0eb56e8821 /kernel | |
| parent | b0cfaffa7e183719436a7a2b1b814afb5748c05c (diff) | |
tracing/kprobe: Wait for disabling all running kprobe handlers
commit a232e270dcb55a70ad3241bc6fc160fd9b5c9e6c upstream.
Wait for disabling all running kprobe handlers when a kprobe
event is disabled, since the caller, trace_remove_event_call()
supposes that a removing event is disabled completely by
disabling the event.
With this change, ftrace can ensure that there is no running
event handlers after disabling it.
Link: http://lkml.kernel.org/r/20130709093526.20138.93100.stgit@mhiramat-M0-7522
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/trace/trace_kprobe.c | 21 |
1 files changed, 17 insertions, 4 deletions
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 9f46e98ba8f2..c209c6ec34ca 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -281,6 +281,8 @@ trace_probe_file_index(struct trace_probe *tp, struct ftrace_event_file *file) static int disable_trace_probe(struct trace_probe *tp, struct ftrace_event_file *file) { + struct ftrace_event_file **old = NULL; + int wait = 0; int ret = 0; mutex_lock(&probe_enable_lock); @@ -314,10 +316,7 @@ disable_trace_probe(struct trace_probe *tp, struct ftrace_event_file *file) } rcu_assign_pointer(tp->files, new); - - /* Make sure the probe is done with old files */ - synchronize_sched(); - kfree(old); + wait = 1; } else tp->flags &= ~TP_FLAG_PROFILE; @@ -326,11 +325,25 @@ disable_trace_probe(struct trace_probe *tp, struct ftrace_event_file *file) disable_kretprobe(&tp->rp); else disable_kprobe(&tp->rp.kp); + wait = 1; } out_unlock: mutex_unlock(&probe_enable_lock); + if (wait) { + /* + * Synchronize with kprobe_trace_func/kretprobe_trace_func + * to ensure disabled (all running handlers are finished). + * This is not only for kfree(), but also the caller, + * trace_remove_event_call() supposes it for releasing + * event_call related objects, which will be accessed in + * the kprobe_trace_func/kretprobe_trace_func. + */ + synchronize_sched(); + kfree(old); /* Ignored if link == NULL */ + } + return ret; } |