From: Linus Torvalds <[email protected]>
To: "Eric W. Biederman" <[email protected]>
Cc: Linux Kernel Mailing List <[email protected]>,
linux-fsdevel <[email protected]>,
io-uring <[email protected]>,
Alexander Viro <[email protected]>,
Olivier Langlois <[email protected]>,
Jens Axboe <[email protected]>,
"Pavel Begunkov>" <[email protected]>,
Oleg Nesterov <[email protected]>
Subject: Re: [RFC] coredump: Do not interrupt dump for TIF_NOTIFY_SIGNAL
Date: Wed, 9 Jun 2021 13:33:36 -0700 [thread overview]
Message-ID: <CAHk-=wjC7GmCHTkoz2_CkgSc_Cgy19qwSQgJGXz+v2f=KT3UOw@mail.gmail.com> (raw)
In-Reply-To: <87h7i694ij.fsf_-_@disp2133>
On Wed, Jun 9, 2021 at 1:17 PM Eric W. Biederman <[email protected]> wrote:
>>
> In short the coredump code deliberately supports being interrupted by
> SIGKILL, and depends upon prepare_signal to filter out all other
> signals.
Hmm.
I have to say, that looks like the core reason for the bug: if you
want to be interrupted by a fatal signal, you shouldn't use
signal_pending(), you should use fatal_signal_pending().
Now, the fact that we haven't cleared TIF_NOTIFY_SIGNAL for the first
signal is clearly the immediate cause of this, but at the same time I
really get the feeling that that coredump aborting code should always
had used fatal_signal_pending().
We do want to be able to abort core-dumps (stuck network filesystems
is the traditional reason), but the fact that it used signal_pending()
looks buggy.
In fact, the very comment in that dump_interrupted() function seems to
acknowledge that signal_pending() is all kinds of silly.
So regardless of the fact that io_uring does seem to have messed up
this part of signals, I think the fix is not to change
signal_pending() to task_sigpending(), but to just do what the comment
suggests we should do.
But also:
> With the io_uring code comes an extra test in signal_pending
> for TIF_NOTIFY_SIGNAL (which is something about asking a task to run
> task_work_run).
Jens, is this still relevant? Maybe we can revert that whole series
now, and make the confusing difference between signal_pending() and
task_sigpending() go away again?
Linus
next parent reply other threads:[~2021-06-09 20:33 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <[email protected]>
[not found] ` <[email protected]>
[not found] ` <87h7i694ij.fsf_-_@disp2133>
2021-06-09 20:33 ` Linus Torvalds [this message]
2021-06-09 20:48 ` [RFC] coredump: Do not interrupt dump for TIF_NOTIFY_SIGNAL Eric W. Biederman
2021-06-09 20:52 ` Linus Torvalds
2021-06-09 21:02 ` Olivier Langlois
2021-06-09 21:05 ` Eric W. Biederman
2021-06-09 21:26 ` Olivier Langlois
2021-06-09 21:56 ` Olivier Langlois
2021-06-10 14:26 ` Eric W. Biederman
2021-06-10 15:17 ` Olivier Langlois
2021-06-10 18:58 ` [CFT}[PATCH] coredump: Limit what can interrupt coredumps Eric W. Biederman
2021-06-10 19:10 ` Linus Torvalds
2021-06-10 19:18 ` Eric W. Biederman
2021-06-10 19:50 ` Linus Torvalds
2021-06-10 20:11 ` [PATCH] " Eric W. Biederman
2021-06-10 21:04 ` Linus Torvalds
2021-06-12 14:36 ` Olivier Langlois
2021-06-12 16:26 ` Jens Axboe
2021-06-14 14:10 ` Oleg Nesterov
2021-06-14 16:37 ` Eric W. Biederman
2021-06-14 16:59 ` Oleg Nesterov
2021-06-15 22:08 ` Eric W. Biederman
2021-06-16 19:23 ` Olivier Langlois
2021-06-16 20:00 ` Eric W. Biederman
2021-06-18 20:05 ` Olivier Langlois
2021-08-05 13:06 ` Olivier Langlois
2021-08-10 21:48 ` Tony Battersby
2021-08-11 20:47 ` Olivier Langlois
2021-08-12 1:55 ` Jens Axboe
2021-08-12 13:53 ` Tony Battersby
2021-08-15 20:42 ` Olivier Langlois
2021-08-16 13:02 ` Pavel Begunkov
2021-08-16 13:06 ` Pavel Begunkov
2021-08-17 18:15 ` Jens Axboe
2021-08-17 18:24 ` Jens Axboe
2021-08-17 19:29 ` Tony Battersby
2021-08-17 19:59 ` Jens Axboe
2021-08-17 21:28 ` Jens Axboe
2021-08-17 21:39 ` Tony Battersby
2021-08-17 22:05 ` Jens Axboe
2021-08-18 14:37 ` Tony Battersby
2021-08-18 14:46 ` Jens Axboe
2021-08-18 2:57 ` Jens Axboe
2021-08-18 2:58 ` Jens Axboe
2021-08-21 10:08 ` Olivier Langlois
2021-08-21 16:47 ` Olivier Langlois
2021-08-21 16:51 ` Jens Axboe
2021-08-21 17:21 ` Olivier Langlois
2021-08-21 9:52 ` Olivier Langlois
2021-08-21 9:48 ` Olivier Langlois
2021-10-22 14:13 ` [RFC] coredump: Do not interrupt dump for TIF_NOTIFY_SIGNAL Pavel Begunkov
2021-12-24 1:34 ` Olivier Langlois
2021-12-24 10:37 ` Pavel Begunkov
2021-12-24 19:52 ` Eric W. Biederman
2021-12-28 11:24 ` Pavel Begunkov
2022-03-14 23:58 ` Eric W. Biederman
[not found] ` <[email protected]>
2022-06-01 3:15 ` Jens Axboe
2022-07-20 16:49 ` [PATCH 0/2] coredump: Allow io_uring using apps to dump to pipes Eric W. Biederman
2022-07-20 16:50 ` [PATCH 1/2] signal: Move stopping for the coredump from do_exit into get_signal Eric W. Biederman
2022-07-20 16:51 ` [PATCH 2/2] coredump: Allow coredumps to pipes to work with io_uring Eric W. Biederman
2022-08-22 21:16 ` Olivier Langlois
2022-08-23 3:35 ` Olivier Langlois
2022-08-23 18:22 ` Eric W. Biederman
2022-08-23 18:27 ` Jens Axboe
2022-08-24 15:11 ` Eric W. Biederman
2022-08-24 15:51 ` Jens Axboe
2022-01-05 19:39 ` [RFC] coredump: Do not interrupt dump for TIF_NOTIFY_SIGNAL Olivier Langlois
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