On 8/21/21 10:47 AM, Olivier Langlois wrote:

On Sat, 2021-08-21 at 06:08 -0400, Olivier Langlois wrote:

quoted

On Tue, 2021-08-17 at 20:57 -0600, Jens Axboe wrote:

quoted

Olivier, I sent a 5.10 version for Nathan, any chance you can test
this
one for the current kernels? Basically this one should work for
5.11+,
and the later 5.10 version is just for 5.10. I'm going to send it
out
separately for review.

I do think this is the right solution, barring a tweak maybe on
testing
notify == TWA_SIGNAL first before digging into the task struct. But
the
principle is sound, and it'll work for other users of TWA_SIGNAL as
well. None right now as far as I can tell, but the live patching is
switching to TIF_NOTIFY_SIGNAL as well which will also cause issues
with
coredumps potentially.

Ok, I am going to give it a shot. This solution is probably superior
to
the previous attempt as it does not inject io_uring dependency into
the
coredump module.

The small extra change that I alluded to in my previous reply will
still be relevant even if we go with your patch...

I'll come back soon with your patch testing result and my small extra
change that I keep teasing about.

Greetings,

Jens,

your patch doesn't compile with 5.12+. AFAIK, the reason is that
JOBCTL_TASK_WORK is gone.

Wouldn't just a call to tracehook_notify_signal from do_coredump be
enough and backward compatible with every possible stable branches?

That version is just for 5.10, the first I posted is applicable to
5.11+

-- 
Jens Axboe