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tracing/kprobes: unregister_trace_probe needs to be called under mutex

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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>
This commit is contained in:
Srikar Dronamraju 2010-06-30 14:15:48 +05:30 committed by Arnaldo Carvalho de Melo
parent b83f920e17
commit 9da79ab83e
1 changed files with 3 additions and 0 deletions
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3
kernel/trace/trace_kprobe.c
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@ -925,14 +925,17 @@ static int create_trace_probe(int argc, char **argv)
pr_info("Delete command needs an event name.\n"); pr_info("Delete command needs an event name.\n");
return -EINVAL; return -EINVAL;
} }
mutex_lock(&probe_lock);
tp = find_probe_event(event, group); tp = find_probe_event(event, group);
if (!tp) { if (!tp) {
mutex_unlock(&probe_lock);
pr_info("Event %s/%s doesn't exist.\n", group, event); pr_info("Event %s/%s doesn't exist.\n", group, event);
return -ENOENT; return -ENOENT;
} }
/* delete an event */ /* delete an event */
unregister_trace_probe(tp); unregister_trace_probe(tp);
free_trace_probe(tp); free_trace_probe(tp);
mutex_unlock(&probe_lock);
return 0; return 0;
} }