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tracing/events: Fix locking imbalance in the filter code

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Américo Wang noticed that we have a locking imbalance in the
error paths of ftrace_profile_set_filter(), causing potential
leakage of event_mutex.

Also clean up other error codepaths related to event_mutex
while at it.

Plus fix an initialized variable in the subsystem filter code.

Reported-by: Américo Wang <xiyou.wangcong@gmail.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <2375c9f90910150247u5ccb8e2at58c764e385ffa490@mail.gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ingo Molnar 2009-10-15 12:24:04 +02:00
parent c171b552a7
commit a66abe7fbf
1 changed files with 16 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
kernel/trace/trace_events_filter.c
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@ -1230,10 +1230,10 @@ static int replace_system_preds(struct event_subsystem *system,
struct filter_parse_state *ps,
char *filter_string)
{
struct event_filter *filter = system->filter;
struct ftrace_event_call *call;
struct event_filter *filter;
int err;
bool fail = true;
int err;
list_for_each_entry(call, &ftrace_events, list) {
@ -1262,7 +1262,7 @@ static int replace_system_preds(struct event_subsystem *system,
if (fail) {
parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0);
return err;
return -EINVAL;
}
return 0;
}
@ -1281,8 +1281,7 @@ int apply_event_filter(struct ftrace_event_call *call, char *filter_string)
if (!strcmp(strstrip(filter_string), "0")) {
filter_disable_preds(call);
remove_filter_string(call->filter);
mutex_unlock(&event_mutex);
return 0;
goto out_unlock;
}
err = -ENOMEM;
@ -1330,8 +1329,7 @@ int apply_subsystem_event_filter(struct event_subsystem *system,
if (!strcmp(strstrip(filter_string), "0")) {
filter_free_subsystem_preds(system);
remove_filter_string(system->filter);
mutex_unlock(&event_mutex);
return 0;
goto out_unlock;
}
err = -ENOMEM;
@ -1386,15 +1384,20 @@ int ftrace_profile_set_filter(struct perf_event *event, int event_id,
if (call->id == event_id)
break;
}
if (!call)
return -EINVAL;
err = -EINVAL;
if (!call)
goto out_unlock;
err = -EEXIST;
if (event->filter)
return -EEXIST;
goto out_unlock;
filter = __alloc_preds();
if (IS_ERR(filter))
return PTR_ERR(filter);
if (IS_ERR(filter)) {
err = PTR_ERR(filter);
goto out_unlock;
}
err = -ENOMEM;
ps = kzalloc(sizeof(*ps), GFP_KERNEL);
@ -1419,6 +1422,7 @@ free_preds:
if (err)
__free_preds(filter);
out_unlock:
mutex_unlock(&event_mutex);
return err;