From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Comment in unregister_trace_probe() says probe_lock will be held when it
gets called. However there is a case where it might called without the
probe_lock being held. Also since we are traversing the probe_list and
deleting an element from the probe_list, probe_lock should be held.
This was first pointed in uprobes traceevent review by Frederic
Weisbecker here. (http://lkml.org/lkml/2010/5/12/106)
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20100630084548.GA10325@linux.vnet.ibm.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
kernel/trace/trace_kprobe.c | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 1b79d1c..8b27c98 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -925,14 +925,17 @@ static int create_trace_probe(int argc, char **argv)
pr_info("Delete command needs an event name.\n");
return -EINVAL;
}
+ mutex_lock(&probe_lock);
tp = find_probe_event(event, group);
if (!tp) {
+ mutex_unlock(&probe_lock);
pr_info("Event %s/%s doesn't exist.\n", group, event);
return -ENOENT;
}
/* delete an event */
unregister_trace_probe(tp);
free_trace_probe(tp);
+ mutex_unlock(&probe_lock);
return 0;
}
--
1.6.2.5
--
