From: "Steven Rostedt (VMware)" Trace event triggers can be called before or after the event has been committed. If it has been called after the commit, there's a possibility that the event no longer exists. Currently, the two post callers is the trigger to disable tracing (traceoff) and the one that will record a stack dump (stacktrace). Neither of them reference the trace event entry record, as that would lead to a race condition that could pass in corrupted data. To prevent any other users of the post data triggers from using the trace event record, pass in NULL to the post call trigger functions for the event record, as they should never need to use them in the first place. This does not fix any bug, but prevents bugs from happening by new post call trigger users. Signed-off-by: Steven Rostedt (VMware) --- include/linux/trace_events.h | 3 +-- kernel/trace/trace.h | 4 ++-- kernel/trace/trace_events_trigger.c | 6 ++---- 3 files changed, 5 insertions(+), 8 deletions(-) diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h index 2bde3eff564c..d1c442d9bd85 100644 --- a/include/linux/trace_events.h +++ b/include/linux/trace_events.h @@ -435,8 +435,7 @@ event_triggers_call(struct trace_event_file *file, void *rec, struct ring_buffer_event *event); extern void event_triggers_post_call(struct trace_event_file *file, - enum event_trigger_type tt, - void *rec, struct ring_buffer_event *event); + enum event_trigger_type tt); bool trace_event_ignore_this_pid(struct trace_event_file *trace_file); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 6fb46a06c9dc..24b666891eaf 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1334,7 +1334,7 @@ event_trigger_unlock_commit(struct trace_event_file *file, trace_buffer_unlock_commit(file->tr, buffer, event, irq_flags, pc); if (tt) - event_triggers_post_call(file, tt, entry, event); + event_triggers_post_call(file, tt); } /** @@ -1367,7 +1367,7 @@ event_trigger_unlock_commit_regs(struct trace_event_file *file, irq_flags, pc, regs); if (tt) - event_triggers_post_call(file, tt, entry, event); + event_triggers_post_call(file, tt); } #define FILTER_PRED_INVALID ((unsigned short)-1) diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c index d251cabcf69a..cc4148bfc01a 100644 --- a/kernel/trace/trace_events_trigger.c +++ b/kernel/trace/trace_events_trigger.c @@ -97,7 +97,6 @@ EXPORT_SYMBOL_GPL(event_triggers_call); * event_triggers_post_call - Call 'post_triggers' for a trace event * @file: The trace_event_file associated with the event * @tt: enum event_trigger_type containing a set bit for each trigger to invoke - * @rec: The trace entry for the event * * For each trigger associated with an event, invoke the trigger * function registered with the associated trigger command, if the @@ -108,8 +107,7 @@ EXPORT_SYMBOL_GPL(event_triggers_call); */ void event_triggers_post_call(struct trace_event_file *file, - enum event_trigger_type tt, - void *rec, struct ring_buffer_event *event) + enum event_trigger_type tt) { struct event_trigger_data *data; @@ -117,7 +115,7 @@ event_triggers_post_call(struct trace_event_file *file, if (data->paused) continue; if (data->cmd_ops->trigger_type & tt) - data->ops->func(data, rec, event); + data->ops->func(data, NULL, NULL); } } EXPORT_SYMBOL_GPL(event_triggers_post_call); -- 2.17.0