diff options
| author | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2018-08-09 15:31:48 -0400 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2018-08-10 15:12:01 -0400 |
| commit | e0a568dcd18bdaa77877d558700ce4d3bbbb12b8 (patch) | |
| tree | 98962d8b1862aa1422e2e79021a6019a5a232a10 /kernel/trace/trace_events_filter.c | |
| parent | b207de3ec531ff364843708c9fea968700aae8fe (diff) | |
tracing: Fix synchronizing to event changes with tracepoint_synchronize_unregister()
Now that some trace events can be protected by srcu_read_lock(tracepoint_srcu),
we need to make sure all locations that depend on this are also protected.
There were many places that did a synchronize_sched() thinking that it was
enough to protect againts access to trace events. This use to be the case,
but now that we use SRCU for _rcuidle() trace events, they may not be
protected by synchronize_sched(), as they may be called in paths that RCU is
not watching for preempt disable.
Fixes: e6753f23d961d ("tracepoint: Make rcuidle tracepoint callers use SRCU")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace_events_filter.c')
| -rw-r--r-- | kernel/trace/trace_events_filter.c | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 893a206bcba4..184c7685d5ea 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -899,7 +899,8 @@ int filter_match_preds(struct event_filter *filter, void *rec) if (!filter) return 1; - prog = rcu_dereference_sched(filter->prog); + /* Protected by either SRCU(tracepoint_srcu) or preempt_disable */ + prog = rcu_dereference_raw(filter->prog); if (!prog) return 1; @@ -1626,10 +1627,10 @@ static int process_system_preds(struct trace_subsystem_dir *dir, /* * The calls can still be using the old filters. - * Do a synchronize_sched() to ensure all calls are + * Do a synchronize_sched() and to ensure all calls are * done with them before we free them. */ - synchronize_sched(); + tracepoint_synchronize_unregister(); list_for_each_entry_safe(filter_item, tmp, &filter_list, list) { __free_filter(filter_item->filter); list_del(&filter_item->list); @@ -1648,7 +1649,7 @@ static int process_system_preds(struct trace_subsystem_dir *dir, kfree(filter); /* If any call succeeded, we still need to sync */ if (!fail) - synchronize_sched(); + tracepoint_synchronize_unregister(); list_for_each_entry_safe(filter_item, tmp, &filter_list, list) { __free_filter(filter_item->filter); list_del(&filter_item->list); @@ -1790,7 +1791,7 @@ int apply_event_filter(struct trace_event_file *file, char *filter_string) event_clear_filter(file); /* Make sure the filter is not being used */ - synchronize_sched(); + tracepoint_synchronize_unregister(); __free_filter(filter); return 0; @@ -1817,7 +1818,7 @@ int apply_event_filter(struct trace_event_file *file, char *filter_string) if (tmp) { /* Make sure the call is done with the filter */ - synchronize_sched(); + tracepoint_synchronize_unregister(); __free_filter(tmp); } } @@ -1847,7 +1848,7 @@ int apply_subsystem_event_filter(struct trace_subsystem_dir *dir, filter = system->filter; system->filter = NULL; /* Ensure all filters are no longer used */ - synchronize_sched(); + tracepoint_synchronize_unregister(); filter_free_subsystem_filters(dir, tr); __free_filter(filter); goto out_unlock; |