From: Aaron Tomlin <atomlin@redhat.com>
To: Jiri Kosina <jikos@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Ulrich Obergfell <uobergfe@redhat.com>,
Don Zickus <dzickus@redhat.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] watchdog: perform all-CPU backtrace in case of hard lockup
Date: Thu, 1 Oct 2015 12:05:57 +0100 [thread overview]
Message-ID: <20151001110557.GS25024@atomlin.usersys.redhat.com> (raw)
In-Reply-To: <alpine.LNX.2.00.1510010942470.30132@pobox.suse.cz>
On Thu 2015-10-01 09:45 +0200, Jiri Kosina wrote:
> That should be fine. Worst case scenario is hardlockup and softlockup
> trigerring 'in parallel' on different CPUs, and all-cpu backtrace being
> triggered twice.
>
> Frankly, I've never seen this happen in practice (hardlockup and
> softlockup triggering at different CPUs at the very same time).
>
> We could possibly make a global 'all_cpus_dump_in_progress' flag so that
> we guarantee only one stream of dumps, but we'd need to convert everybody
> using this facility (e.g. RCU stall detector, and whoever else) to be
> aware of it as well, otherwise it wouldn't make too much sense.
>
> Something to add to TODO I guess.
This could indeed be worth further investigation.
--
Aaron Tomlin
next prev parent reply other threads:[~2015-10-01 11:06 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-25 11:15 [PATCH] watchdog: perform all-CPU backtrace in case of hard lockup Jiri Kosina
2015-09-25 14:44 ` Don Zickus
2015-10-01 7:37 ` Aaron Tomlin
2015-10-01 7:45 ` Jiri Kosina
2015-10-01 11:05 ` Aaron Tomlin [this message]
2015-10-12 21:14 ` Don Zickus
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