linux-mm.kvack.org archive mirror
 help / color / mirror / Atom feed
From: SeongJae Park <sj@kernel.org>
To: SeongJae Park <sj@kernel.org>
Cc: Xinyu Zheng <zhengxinyu6@huawei.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	"Paul E . McKenney" <paulmck@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	damon@lists.linux.dev, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, zouyipeng@huawei.com,
	Hugh Dickins <hughd@google.com>
Subject: Re: [BUG REPORT] mm/damon: softlockup when kdamond walk page with cpu hotplug
Date: Thu, 18 Sep 2025 01:57:00 -0700	[thread overview]
Message-ID: <20250918085701.59085-1-sj@kernel.org> (raw)
In-Reply-To: <20250918085249.58966-1-sj@kernel.org>

On Thu, 18 Sep 2025 01:52:49 -0700 SeongJae Park <sj@kernel.org> wrote:

> Hello,
> 
> On Thu, 18 Sep 2025 03:00:29 +0000 Xinyu Zheng <zhengxinyu6@huawei.com> wrote:
> 
> > A softlockup issue was found with stress test:
[...]
> damon_mkold_pmd_entry() calls pte_offset_map_lock().  If the call returns an
> error, damon_mkold_pmd_entry() sets walk->action as ACTION_AGAIN, to retry.  If
> the pte_offset_map_lock() continues fails, infinite loop can happen.  I
> understand the loop you mentioned above is this case.
> 
> The error handling (retrying) was introduced by commit 7780d04046a2
> ("mm/pagewalkers: ACTION_AGAIN if pte_offset_map_lock() fails").

I added Hugh to this thread from the original mail of this reply, because he is
the author of the commit.  I should clarified this on the original mail but
forgot saying that, sorry.


Thanks,
SJ

[...]


  reply	other threads:[~2025-09-18  8:57 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-09-18  3:00 Xinyu Zheng
2025-09-18  8:52 ` SeongJae Park
2025-09-18  8:57   ` SeongJae Park [this message]
2025-09-20  3:56   ` Hugh Dickins
2025-09-20 10:42     ` SeongJae Park
2025-09-22  3:48       ` Xinyu Zheng
2025-09-25 11:11       ` Xinyu Zheng
2025-09-30  0:49         ` SeongJae Park

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=20250918085701.59085-1-sj@kernel.org \
    --to=sj@kernel.org \
    --cc=akpm@linux-foundation.org \
    --cc=damon@lists.linux.dev \
    --cc=hughd@google.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=paulmck@kernel.org \
    --cc=peterz@infradead.org \
    --cc=zhengxinyu6@huawei.com \
    --cc=zouyipeng@huawei.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox