system/linux
system/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux synced 2024-11-05 18:23:50 +00:00
Code Issues Projects Releases Packages Wiki Activity

tracing: Add rcu dereference annotation for test func that touches filter->prog

Browse source 
A boot up test function update_pred_fn() dereferences filter->prog without
the proper rcu annotation.

To do this, we must also take the event_mutex first. Normally, this isn't
needed because this test function can not race with other use cases that
touch the event filters (it is disabled if any events are enabled).

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Fixes: 80765597bc ("tracing: Rewrite filter logic to be simpler and faster")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (VMware) 2018-04-05 15:20:26 -04:00
parent 1f3b0faa3e
commit 8ec8405f08
1 changed files with 6 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

7
kernel/trace/trace_events_filter.c
View file

@ -2155,7 +2155,8 @@ static int test_pred_visited_fn(struct filter_pred *pred, void *event)
static void update_pred_fn(struct event_filter *filter, char *fields)
{
struct prog_entry *prog = filter->prog;
struct prog_entry *prog = rcu_dereference_protected(filter->prog,
lockdep_is_held(&event_mutex));
int i;
for (i = 0; prog[i].pred; i++) {
@ -2197,6 +2198,8 @@ static __init int ftrace_test_event_filter(void)
break;
}
/* Needed to dereference filter->prog */
mutex_lock(&event_mutex);
/*
* The preemption disabling is not really needed for self
* tests, but the rcu dereference will complain without it.
@ -2209,6 +2212,8 @@ static __init int ftrace_test_event_filter(void)
err = filter_match_preds(filter, &d->rec);
preempt_enable();
mutex_unlock(&event_mutex);
__free_filter(filter);
if (test_pred_visited) {