Re: [PATCH RFC 0/2] Add basic tracing support for m68k

From: Steven Rostedt
Date: Tue Nov 19 2024 - 10:27:06 EST


On Tue, 19 Nov 2024 15:24:00 +0100
Jean-Michel Hautbois <jeanmichel.hautbois@xxxxxxxxxx> wrote:

> Indeed printf gave me clues !
> It appears to be a bug in libtracefs (v1.8.1). rtla segfaults when
> calling tracefs_local_events() in trace_instance_init().
>
> Debugging libtracefs pointed me to the load_events() function, and the
> segfault happens after tep_parse_event() is called for
> "/sys/kernel/debug/tracing/events/vmscan/mm_vmscan_write_folio/format".
>
> Going through the calls I get to event_read_print_args().
> I changed libtraceevent log level to get the warnings, and it says:
> libtraceevent: Resource temporarily unavailable
> unknown op '.'
> Segmentation fault

Can you do me a favor and send me privately a tarball of:

# cp -r /sys/kernel/tracing/events /tmp/events
# cd /tmp
# tar -cvjf events.tar.bz2 events

You can't call tar on the /sys/kernel/tracing files as those are pseudo
files with size of zero, and tar will just record empty files :-p

-- Steve