From: Oleg Nesterov <oleg@redhat.com>
To: Mandeep Singh Baines <msb@chromium.org>
Cc: linux-kernel@vger.kernel.org, Ben Chan <benchan@chromium.org>,
Tejun Heo <tj@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
"Rafael J. Wysocki" <rjw@sisk.pl>, Ingo Molnar <mingo@redhat.com>
Subject: Re: [PATCH 5/5] coredump: abort core dump piping only due to a fatal signal
Date: Fri, 15 Feb 2013 16:01:17 +0100 [thread overview]
Message-ID: <20130215150117.GB30829@redhat.com> (raw)
In-Reply-To: <1360885096-21207-5-git-send-email-msb@chromium.org>
On 02/14, Mandeep Singh Baines wrote:
>
> This patch makes wait_for_dump_helpers() not to abort piping the core
> dump data when the crashing process has received any but a fatal signal
> (SIGKILL). The rationale is that a crashing process may still receive
> uninteresting signals such as SIGCHLD when its core dump data is being
> redirected to a helper application.
You already sent this change in the past ;) and I already reviewed it.
It is not enough and imho not good. Damn, I'll try very much to make the
patches on weekend...
> - while ((pipe->readers > 1) && (!signal_pending(current))) {
> + while ((pipe->readers > 1) && (!fatal_signal_pending(current))) {
This turns pipe_wait() belowe into the busy-wait loop if signal_pending().
Not good. And not enough, there are other reasons why coredump can fail
if the signal is pending.
> wake_up_interruptible_sync(&pipe->wait);
> kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
> pipe_wait(pipe);
> + pipe_unlock(pipe);
> + try_to_freeze();
Oh, yes. One of the problems with coredump/signals is freezer. Not sure
what should we do...
But if we add try_to_freeze() here, we need to add more try_to_freeze's,
think about dumping the huge core on the slow media.
Oleg.
next prev parent reply other threads:[~2013-02-15 15:02 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-14 23:38 [PATCH 1/5] vfork: don't freezer_count() for in-kernel users of CLONE_VFORK Mandeep Singh Baines
2013-02-14 23:38 ` [PATCH 2/5] lockdep: check that no locks held at freeze time Mandeep Singh Baines
2013-02-15 11:16 ` Ingo Molnar
2013-02-15 15:44 ` Oleg Nesterov
2013-02-14 23:38 ` [PATCH 3/5] coredump: cleanup the waiting for coredump_finish code Mandeep Singh Baines
2013-02-15 14:53 ` Oleg Nesterov
2013-02-15 23:30 ` Andrew Morton
2013-02-14 23:38 ` [PATCH 4/5] coredump: use a freezable_schedule for the coredump_finish wait Mandeep Singh Baines
2013-02-14 23:38 ` [PATCH 5/5] coredump: abort core dump piping only due to a fatal signal Mandeep Singh Baines
2013-02-15 15:01 ` Oleg Nesterov [this message]
2013-02-16 1:20 ` Mandeep Singh Baines
2013-02-16 17:05 ` Oleg Nesterov
2013-02-15 23:25 ` Andrew Morton
2013-02-16 0:09 ` [PATCH v3] coredump: ignore non-fatal signals when core dumping to a pipe Mandeep Singh Baines
2013-02-16 0:57 ` [PATCH v4] " Mandeep Singh Baines
2013-02-15 15:28 ` [PATCH 1/5] vfork: don't freezer_count() for in-kernel users of CLONE_VFORK Oleg Nesterov
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