All of lore.kernel.org
 help / color / mirror / Atom feed
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>


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

WARNING: multiple messages have this Message-ID (diff)
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>


  reply	other threads:[~2024-05-09 15:30 UTC|newest]

Thread overview: 8+ 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
2024-05-07 13:18 ` Rik van Riel
2024-05-09  3:52 ` Baoquan He
2024-05-09  3:52   ` Baoquan He
2024-05-09 13:41   ` Rik van Riel
2024-05-09 13:41     ` Rik van Riel
2024-05-09 15:30     ` Baoquan He [this message]
2024-05-09 15:30       ` Baoquan He

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=ZjzsC8KwEoDzAZBt@fedora \
    --to=bhe@redhat.com \
    --cc=akpm@linux-foundation.org \
    --cc=dyoung@redhat.com \
    --cc=kernel-team@meta.com \
    --cc=kexec@lists.infradead.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=riel@surriel.com \
    --cc=vgoyal@redhat.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.