On Mon, 28 Feb 2022 08:30:29 +0100 <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > The patch below does not apply to the 4.14-stable tree. > If someone wants it applied there, or to any other stable or longterm > tree, then please email the backport, including the original git commit > id to <stable@xxxxxxxxxxxxxxx>. > The following should work for 4.14. Again, 4.9 and earlier requires a lot more work than I have time for. -- Steve >From ce33c845b030c9cf768370c951bc699470b09fa7 Mon Sep 17 00:00:00 2001 From: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx> Date: Sun, 20 Feb 2022 23:49:57 +0100 Subject: [PATCH] tracing: Dump stacktrace trigger to the corresponding instance 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 | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) Index: linux-test.git/kernel/trace/trace_events_trigger.c =================================================================== --- linux-test.git.orig/kernel/trace/trace_events_trigger.c 2022-04-20 19:03:45.329706898 -0400 +++ linux-test.git/kernel/trace/trace_events_trigger.c 2022-04-20 19:05:35.323694306 -0400 @@ -1156,7 +1156,14 @@ static __init int register_trigger_snaps static void stacktrace_trigger(struct event_trigger_data *data, void *rec) { - trace_dump_stack(STACK_SKIP); + struct trace_event_file *file = data->private_data; + unsigned long flags; + + if (file) { + local_save_flags(flags); + __trace_stack(file->tr, flags, STACK_SKIP, preempt_count()); + } else + trace_dump_stack(STACK_SKIP); } static void
