From: Andrew Morton <akpm@linux-foundation.org>
To: syzbot <syzbot+12ee2725d5fde63a9c96@syzkaller.appspotmail.com>
Cc: axelrasmussen@google.com, baohua@kernel.org,
baolin.wang@linux.alibaba.com, cgroups@vger.kernel.org,
david@kernel.org, hannes@cmpxchg.org, kasong@tencent.com,
kernel-team@meta.com, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, ljs@kernel.org, mhocko@kernel.org,
mhocko@suse.com, muchun.song@linux.dev, qi.zheng@linux.dev,
roman.gushchin@linux.dev, shakeel.butt@linux.dev,
syzkaller-bugs@googlegroups.com, weixugc@google.com,
yuanchu@google.com
Subject: Re: [syzbot] [mm?] WARNING in set_mm_walk
Date: Wed, 12 Aug 2026 14:03:58 -0700 [thread overview]
Message-ID: <20260812140358.343927ad8d0955b67c4e7ad5@linux-foundation.org> (raw)
In-Reply-To: <6a7c6670.3668565d.e8814.0012.GAE@google.com>
On Wed, 12 Aug 2026 05:26:24 -0700 syzbot <syzbot+12ee2725d5fde63a9c96@syzkaller.appspotmail.com> wrote:
> syzbot has found a reproducer for the following issue on:
>
> HEAD commit: f5bbbfec59b4 Merge tag 'probes-fixes-v7.2-rc7' of git://gi..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=11f44c79580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=c44651ea7dd2f307
> dashboard link: https://syzkaller.appspot.com/bug?extid=12ee2725d5fde63a9c96
> compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10d11149580000
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+12ee2725d5fde63a9c96@syzkaller.appspotmail.com
>
> ------------[ cut here ]------------
> current_is_kswapd()
> WARNING: mm/vmscan.c:3800 at set_mm_walk+0x210/0x270 mm/vmscan.c:3800, CPU#2: kswapd0/111
Thanks. Shakeel is working on a series which will fix this by removing
the calling code. But it isn't a minor patch.
Shakeel, it would be good to have a backportable quick-fix to make this
warning go away?
> Modules linked in:
> CPU: 2 UID: 0 PID: 111 Comm: kswapd0 Not tainted syzkaller #0 PREEMPT(full)
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
> RIP: 0010:set_mm_walk+0x210/0x270 mm/vmscan.c:3800
> Code: 13 00 00 4d 8d 7d 08 e9 f7 fe ff ff e8 19 f7 2a 00 e9 b7 fe ff ff e8 7f 68 ba ff 90 0f 0b 90 e9 d2 fe ff ff e8 71 68 ba ff 90 <0f> 0b 90 e9 74 ff ff ff 4c 89 ff e8 20 f7 2a 00 e9 4e fe ff ff 48
> RSP: 0018:ffffc9000272f2b8 EFLAGS: 00010293
> RAX: 0000000000000000 RBX: ffff888023f04a80 RCX: ffffffff82500a88
> RDX: ffff888023f04a80 RSI: ffffffff82500b0f RDI: ffff888023f04a80
> RBP: 0000000000020000 R08: 0000000000000005 R09: 0000000000000000
> R10: 0000000000020000 R11: 0000000000000000 R12: 0000000000000000
> R13: ffffc9000272fc38 R14: 0000000000000001 R15: ffffc9000272fc40
> FS: 0000000000000000(0000) GS:ffff8880d5fec000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00005643a2ed4168 CR3: 000000003c7ec000 CR4: 0000000000352ef0
> Call Trace:
> <TASK>
> try_to_inc_max_seq+0xf0/0x1090 mm/vmscan.c:4023
> try_to_shrink_lruvec+0x4bd/0x6b0 mm/vmscan.c:4977
> lru_gen_shrink_lruvec mm/vmscan.c:5128 [inline]
> shrink_lruvec+0x31e/0x25b0 mm/vmscan.c:5888
> mem_cgroup_shrink_node+0x227/0x6a0 mm/vmscan.c:6753
> mem_cgroup_soft_reclaim mm/memcontrol-v1.c:312 [inline]
> memcg1_soft_limit_reclaim+0x2d5/0x830 mm/memcontrol-v1.c:362
> balance_pgdat+0xa11/0x1f00 mm/vmscan.c:7177
> kswapd+0x556/0xb50 mm/vmscan.c:7462
> kthread+0x370/0x450 kernel/kthread.c:436
> ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
> ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
> </TASK>
next prev parent reply other threads:[~2026-08-12 21:03 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <6a7a6929.b50370da.49fe0.005e.GAE@google.com>
2026-08-12 12:26 ` [syzbot] [mm?] WARNING in set_mm_walk syzbot
2026-08-12 21:03 ` Andrew Morton [this message]
2026-08-12 21:41 ` Shakeel Butt
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=20260812140358.343927ad8d0955b67c4e7ad5@linux-foundation.org \
--to=akpm@linux-foundation.org \
--cc=axelrasmussen@google.com \
--cc=baohua@kernel.org \
--cc=baolin.wang@linux.alibaba.com \
--cc=cgroups@vger.kernel.org \
--cc=david@kernel.org \
--cc=hannes@cmpxchg.org \
--cc=kasong@tencent.com \
--cc=kernel-team@meta.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=ljs@kernel.org \
--cc=mhocko@kernel.org \
--cc=mhocko@suse.com \
--cc=muchun.song@linux.dev \
--cc=qi.zheng@linux.dev \
--cc=roman.gushchin@linux.dev \
--cc=shakeel.butt@linux.dev \
--cc=syzbot+12ee2725d5fde63a9c96@syzkaller.appspotmail.com \
--cc=syzkaller-bugs@googlegroups.com \
--cc=weixugc@google.com \
--cc=yuanchu@google.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