From: Baoquan He <bhe@redhat.com>
To: Rik van Riel <riel@surriel.com>
Cc: akpm@linux-foundation.org, Vivek Goyal <vgoyal@redhat.com>,
Dave Young <dyoung@redhat.com>,
kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org, kernel-team@meta.com
Subject: Re: [PATCH] fs/proc: fix softlockup in __read_vmcore
Date: Thu, 9 May 2024 23:30:19 +0800 [thread overview]
Message-ID: <ZjzsC8KwEoDzAZBt@fedora> (raw)
In-Reply-To: <cfa4ec0f8f26ffceb6adcea96a182736519886ef.camel@surriel.com>
On 05/09/24 at 09:41am, Rik van Riel wrote:
> On Thu, 2024-05-09 at 11:52 +0800, Baoquan He wrote:
> > Hi,
> >
> > On 05/07/24 at 09:18am, Rik van Riel wrote:
> > > While taking a kernel core dump with makedumpfile on a larger
> > > system,
> > > softlockup messages often appear.
> > >
> > > While softlockup warnings can be harmless, they can also interfere
> > > with things like RCU freeing memory, which can be problematic when
> > > the kdump kexec image is configured with as little memory as
> > > possible.
> > >
> > > Avoid the softlockup, and give things like work items and RCU a
> > > chance to do their thing during __read_vmcore by adding a
> > > cond_resched.
> >
> > Thanks for fixing this.
> >
> > By the way, is it easy to reproduce? And should we add some trace of
> > the
> > softlockup into log so that people can search for it and confirm when
> > encountering it?
>
> It is pretty easy to reproduce, but it does not happen all the time.
> With millions of systems, even rare errors are common :)
>
> However, we have been running with this fix for long enough (we
> deployed it in order to test it) that I don't think we have the
> warning stored any more. Those logs were rotated out long ago.
OK, thanks for the explanation.
Acked-by: Baoquan He <bhe@redhat.com>
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prev parent reply other threads:[~2024-05-09 15:30 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-07 13:18 [PATCH] fs/proc: fix softlockup in __read_vmcore Rik van Riel
2024-05-09 3:52 ` Baoquan He
2024-05-09 13:41 ` Rik van Riel
2024-05-09 15:30 ` Baoquan He [this message]
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