On Tue, 16 Aug 2022 10:57:20 -0400
Alan Stern [off-list ref] wrote:

quoted

static int trace_die_panic_handler(struct notifier_block *self,
				unsigned long ev, void *unused)
{
	if (!ftrace_dump_on_oops)
		return NOTIFY_DONE;

	/* The die notifier requires DIE_OOPS to trigger */
	if (self == &trace_die_notifier && ev != DIE_OOPS)
		return NOTIFY_DONE;

	ftrace_dump(ftrace_dump_on_oops);

	return NOTIFY_DONE;
}  

Or better yet:

	if (ftrace_dump_on_oops) {

		/* The die notifier requires DIE_OOPS to trigger */
		if (self != &trace_die_notifier || ev == DIE_OOPS)
			ftrace_dump(ftrace_dump_on_oops);
	}
	return NOTIFY_DONE;

That may be more consolidated but less easy to read and follow. This is far
from a fast path.

As I maintain this bike-shed, I prefer the one I suggested ;-)

-- Steve