[for-linus][PATCH 02/13] tracing: Dump stacktrace trigger to the corresponding instance

From: Steven Rostedt
Date: Fri Feb 25 2022 - 11:52:53 EST


From: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>

The stacktrace event trigger is not dumping the stacktrace to the instance
where it was enabled, but to the global "instance."

Use the private_data, pointing to the trigger file, to figure out the
corresponding trace instance, and use it in the trigger action, like
snapshot_trigger does.

Link: https://lkml.kernel.org/r/afbb0b4f18ba92c276865bc97204d438473f4ebc.1645396236.git.bristot@xxxxxxxxxx

Cc: stable@xxxxxxxxxxxxxxx
Fixes: ae63b31e4d0e2 ("tracing: Separate out trace events from global variables")
Reviewed-by: Tom Zanussi <zanussi@xxxxxxxxxx>
Tested-by: Tom Zanussi <zanussi@xxxxxxxxxx>
Signed-off-by: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
---
kernel/trace/trace_events_trigger.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index d00fee705f9c..e0d50c9577f3 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -1540,7 +1540,12 @@ stacktrace_trigger(struct event_trigger_data *data,
struct trace_buffer *buffer, void *rec,
struct ring_buffer_event *event)
{
- trace_dump_stack(STACK_SKIP);
+ struct trace_event_file *file = data->private_data;
+
+ if (file)
+ __trace_stack(file->tr, tracing_gen_ctx(), STACK_SKIP);
+ else
+ trace_dump_stack(STACK_SKIP);
}

static void
--
2.34.1