From: Oleg Nesterov <oleg@redhat.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Andy Lutomirski <luto@kernel.org>, Kees Cook <kees@kernel.org>,
Kusaram Devineni <kusaram@devineni.in>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@kernel.org>, Will Drewry <wad@chromium.org>,
linux-kernel@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Christian Brauner <brauner@kernel.org>
Subject: Re: [PATCH v2 00/14] Short circuit delivery for coredump signals
Date: Fri, 10 Jul 2026 16:58:21 +0200 [thread overview]
Message-ID: <alEIjTzN3waMTfyv@redhat.com> (raw)
In-Reply-To: <87mrw0wez9.fsf@email.froward.int.ebiederm.org>
On 07/09, Eric W. Biederman wrote:
>
> Oleg Nesterov <oleg@redhat.com> writes:
>
> > Hmm. And it seems that V2 doesn't fix the problem I noticed in V1: the dumper
> > thread can be wrong.
> >
> > The first thread which calls get_signal() -> dequeue_exit_signal() will
> > initiate the coredumping, not necessary the faulting thread. This looks
> > very wrong to me.
...
> With the signal on the shared_pending queue any thread can initiate the
> core dump without problems.
Yes,
> The only other effect I can see is that the order of the threads notes
> as written into the coredump with fill_note_info will be different.
> Perhaps a debugger takes that as a signal to report which thread has
> died?
AFAIK gdb assumes that the the first NT_PRSTATUS in the core dump is the
"crashed thread".
If the wrong thread is the dumper, the developer will see the unrelated stack
trace / etc. How can the user find the faulted thread which actually triggered
the coredump?
I think this is another regression which should be fixed.
Oleg.
next prev parent reply other threads:[~2026-07-10 14:58 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-19 13:27 [PATCH v2 1/3] signal: change force_sig_info_to_task() to call __send_signal_locked() Oleg Nesterov
2026-06-19 13:27 ` [PATCH v2 2/3] signal: turn the "bool force" arg of __send_signal_locked() into "int flags" Oleg Nesterov
2026-07-06 13:23 ` Bradley Morgan
2026-06-19 13:28 ` [PATCH v2 3/3] signal: fix evasion of SA_IMMUTABLE signals Oleg Nesterov
2026-07-06 13:23 ` Bradley Morgan
2026-06-26 16:52 ` [PATCH 0/11] Short circuit delivery for coredump signals Eric W. Biederman
2026-06-26 16:54 ` [PATCH 01/11] signal: Compute the exit_code in get_signal Eric W. Biederman
2026-06-26 16:54 ` [PATCH 02/11] signal: In get_signal call do_exit when it is unnecessary to shoot down threads Eric W. Biederman
2026-06-26 16:55 ` [PATCH 03/11] signal: Bring down all threads when handling a non-coredump fatal signal Eric W. Biederman
2026-06-26 16:55 ` [PATCH 04/11] signal: Move stopping for the coredump from do_exit into get_signal Eric W. Biederman
2026-06-26 16:56 ` [PATCH 05/11] signal: Move audit_core_dumps from do_coredump " Eric W. Biederman
2026-06-26 16:57 ` [PATCH 06/11] coredump: In zap_threads complete startup if there is no need to wait Eric W. Biederman
2026-06-26 16:57 ` [PATCH 07/11] signal: Use the thread killing in get_signal for coredumps Eric W. Biederman
2026-06-26 16:58 ` [PATCH 08/11] exit: Make do_group_exit static Eric W. Biederman
2026-06-26 16:59 ` [PATCH 09/11] signal: Dequeue fatal signals Eric W. Biederman
2026-06-26 16:59 ` [PATCH 10/11] signal: Short circuit deliver coredump signals Eric W. Biederman
2026-06-26 17:00 ` [PATCH 11/11] signal: Remove SA_IMMUTABLE Eric W. Biederman
2026-06-28 14:29 ` [PATCH 0/11] Short circuit delivery for coredump signals Oleg Nesterov
2026-06-29 6:22 ` Eric W. Biederman
2026-06-29 17:45 ` Eric W. Biederman
2026-07-02 10:36 ` Oleg Nesterov
2026-07-03 20:16 ` Eric W. Biederman
2026-07-05 15:54 ` Oleg Nesterov
2026-07-06 9:21 ` Christian Brauner
2026-07-06 12:30 ` Eric W. Biederman
2026-07-06 15:58 ` Christian Brauner
2026-07-03 21:35 ` [PATCH v2 00/14] " Eric W. Biederman
2026-07-03 21:36 ` [PATCH 01/14] signal: Generalize posixtimer_queue_sigqueue into enqueue_signal Eric W. Biederman
2026-07-06 12:54 ` Bradley Morgan
2026-07-07 11:21 ` Oleg Nesterov
2026-07-07 12:23 ` Eric W. Biederman
2026-07-03 21:37 ` [PATCH 02/14] signal: Factor out sig_blocked from sig_ignored Eric W. Biederman
2026-07-06 13:01 ` Bradley Morgan
2026-07-03 21:37 ` [PATCH 03/14] signal: More accurate ignoring of signals based on sig_can_short_circuit Eric W. Biederman
2026-07-06 13:02 ` Bradley Morgan
2026-07-03 21:38 ` [PATCH 04/14] signal: Use sig_can_short_circuit to improve fatal signal delivery Eric W. Biederman
2026-07-06 13:03 ` Bradley Morgan
2026-07-03 21:39 ` [PATCH 05/14] signal: Compute the exit_code in get_signal Eric W. Biederman
2026-07-06 13:03 ` Bradley Morgan
2026-07-03 21:39 ` Eric W. Biederman
2026-07-03 21:40 ` [PATCH 06/14] signal: In get_signal call do_exit when it is unnecessary to shoot down threads Eric W. Biederman
2026-07-06 13:04 ` Bradley Morgan
2026-07-03 21:40 ` [PATCH 07/14] signal: Bring down all threads when handling a non-coredump fatal signal Eric W. Biederman
2026-07-06 13:05 ` Bradley Morgan
2026-07-03 21:41 ` [PATCH 08/14] signal: Move stopping for the coredump from do_exit into get_signal Eric W. Biederman
2026-07-06 13:08 ` Bradley Morgan
2026-07-03 21:41 ` [PATCH 09/14] signal: Move audit_core_dumps from do_coredump " Eric W. Biederman
2026-07-06 13:08 ` Bradley Morgan
2026-07-03 21:42 ` [PATCH 10/14] coredump: In zap_threads complete startup if there is no need to wait Eric W. Biederman
2026-07-06 13:09 ` Bradley Morgan
2026-07-03 21:43 ` [PATCH 11/14] signal: Use the thread killing in get_signal for coredumps Eric W. Biederman
2026-07-06 13:13 ` Bradley Morgan
2026-07-03 21:43 ` [PATCH 12/14] exit: Make do_group_exit static Eric W. Biederman
2026-07-06 13:14 ` Bradley Morgan
2026-07-03 21:44 ` [PATCH 13/14] signal: Dequeue fatal signals Eric W. Biederman
2026-07-06 13:16 ` Bradley Morgan
2026-07-03 21:44 ` [PATCH 14/14] signal: Short circuit deliver coredump signals Eric W. Biederman
2026-07-06 13:17 ` Bradley Morgan
2026-07-07 11:13 ` [PATCH v2 00/14] Short circuit delivery for " Oleg Nesterov
2026-07-07 12:15 ` Oleg Nesterov
2026-07-09 11:59 ` Eric W. Biederman
2026-07-10 14:58 ` Oleg Nesterov [this message]
2026-07-09 12:28 ` Eric W. Biederman
2026-07-06 13:18 ` [PATCH 0/11] " Bradley Morgan
2026-07-06 13:23 ` [PATCH v2 1/3] signal: change force_sig_info_to_task() to call __send_signal_locked() Bradley Morgan
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