This is a note to let you know that I've just added the patch titled
tracing/kprobe: Wait for disabling all running kprobe handlers
to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tracing-kprobe-wait-for-disabling-all-running-kprobe-handlers.patch
and it can be found in the queue-3.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From a232e270dcb55a70ad3241bc6fc160fd9b5c9e6c Mon Sep 17 00:00:00 2001
From: Masami Hiramatsu <[email protected]>
Date: Tue, 9 Jul 2013 18:35:26 +0900
Subject: tracing/kprobe: Wait for disabling all running kprobe handlers
From: Masami Hiramatsu <[email protected]>
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 <[email protected]>
Signed-off-by: Steven Rostedt <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
kernel/trace/trace_kprobe.c | 21 +++++++++++++++++----
1 file changed, 17 insertions(+), 4 deletions(-)
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -281,6 +281,8 @@ trace_probe_file_index(struct trace_prob
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 *
}
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 *
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;
}
Patches currently in stable-queue which might be from
[email protected] are
queue-3.10/tracing-kprobe-wait-for-disabling-all-running-kprobe-handlers.patch
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