[tip:tracing/core] tracing/events: fix concurrent access to ftrace_events list, fix

tip-bot for Li Zefan
2009-05-07T09:21:24Z

Commit-ID: d94fc523f3c35bd8013f04827e94756cbc0212f4
Gitweb: http://git.kernel.org/tip/d94fc523f3c35bd8013f04827e94756cbc0212f4
Author: Li Zefan <lizf@cn.fujitsu.com>
AuthorDate: Thu, 7 May 2009 15:11:15 +0800
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Thu, 7 May 2009 10:07:28 +0200

tracing/events: fix concurrent access to ftrace_events list, fix

In filter_add_subsystem_pred() we should release event_mutex before
calling filter_free_subsystem_preds(), since both functions hold
event_mutex.

[ Impact: fix deadlock when writing invalid pred into subsystem filter ]

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: tzanussi@gmail.com
Cc: a.p.zijlstra@chello.nl
Cc: fweisbec@gmail.com
Cc: rostedt@goodmis.org
LKML-Reference: <4A028993.7020509@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

---
kernel/trace/trace_events_filter.c | 5 +++--
1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 8c62e5b..85ad6a8 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -636,14 +636,15 @@ static int filter_add_subsystem_pred(struct filter_parse_state *ps,

err = filter_add_pred(ps, call, pred);
if (err) {
+ mutex_unlock(&event_mutex);
filter_free_subsystem_preds(system);
parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0);
- break;
+ goto out;
}
replace_filter_string(call->filter, filter_string);
}
mutex_unlock(&event_mutex);
-
+out:
return err;
}