From: Steven Rostedt <[email protected]> The enable_data variable gets freed on most error paths in event_enable_trigger_parse(). Use free() to free it and just before returning normally, call retain_and_null_ptr(enable_data) just before a successful exit to keep it from being freed. On success, the enable_data is assigned to the trigger_data->private_data field.
Also add a comment to why event_trigger_free(trigger_data) is being called before a successful exit. Reviewed-by: Masami Hiramatsu (Google) <[email protected]> Signed-off-by: Steven Rostedt <[email protected]> --- Changes since v1: https://patch.msgid.link/[email protected] - s/no_return_ptr/retain_and_null_ptr/ as no_return_ptr() has __must_check (Sashiko) - Added a comment to explain the last event_trigger_free() before a successful exit. kernel/trace/trace_events_trigger.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c index 655db2e82513..87601c2560d0 100644 --- a/kernel/trace/trace_events_trigger.c +++ b/kernel/trace/trace_events_trigger.c @@ -1739,7 +1739,7 @@ int event_enable_trigger_parse(struct event_command *cmd_ops, char *glob, char *cmd, char *param_and_filter) { struct trace_event_file *event_enable_file; - struct enable_trigger_data *enable_data; + struct enable_trigger_data *enable_data __free(kfree) = NULL; struct event_trigger_data *trigger_data; struct trace_array *tr = file->tr; char *param, *filter; @@ -1789,17 +1789,13 @@ int event_enable_trigger_parse(struct event_command *cmd_ops, enable_data->file = event_enable_file; trigger_data = trigger_data_alloc(cmd_ops, cmd, param, enable_data); - if (!trigger_data) { - kfree(enable_data); + if (!trigger_data) return ret; - } if (remove) { event_trigger_unregister(cmd_ops, file, glob+1, trigger_data); kfree(trigger_data); - kfree(enable_data); - ret = 0; - return ret; + return 0; } /* Up the trigger_data count to make sure nothing frees it on failure */ @@ -1828,7 +1824,12 @@ int event_enable_trigger_parse(struct event_command *cmd_ops, if (ret) goto out_disable; + /* Release the above reference taken for modules */ event_trigger_free(trigger_data); + + /* The enabled_data is assigned to trigger_data->private_data */ + retain_and_null_ptr(enable_data); + return ret; out_disable: trace_event_enable_disable(event_enable_file, 0, 1); @@ -1837,7 +1838,6 @@ int event_enable_trigger_parse(struct event_command *cmd_ops, out_free: event_trigger_reset_filter(cmd_ops, trigger_data); event_trigger_free(trigger_data); - kfree(enable_data); return ret; } -- 2.53.0
