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b=M7L/CM2k5o4Ik35mAzj3NgcfHzwZQf6D1hc7uET1/UnSKnP7AKT2juBm3Bvlso8kN cRNA7/EvQwBAc6qwMlcJggMbUrw1oxKpiBKp5ZRZus38UshDBOW7V1uOqjP1OtQUf5 boGRAVO0JuJGU8VWcTWjX4TYLFQeImnlLMw3AknE= Date: Wed, 12 Aug 2026 14:03:58 -0700 From: Andrew Morton To: syzbot 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 Message-Id: <20260812140358.343927ad8d0955b67c4e7ad5@linux-foundation.org> In-Reply-To: <6a7c6670.3668565d.e8814.0012.GAE@google.com> References: <6a7a6929.b50370da.49fe0.005e.GAE@google.com> <6a7c6670.3668565d.e8814.0012.GAE@google.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspam-User: X-Stat-Signature: xzbcrmtgo85oiupt5z1ewuf9s53y3h7u X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 05CBC100005 X-HE-Tag: 1786568639-730597 X-HE-Meta: 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 KyZ/IwIu 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, 12 Aug 2026 05:26:24 -0700 syzbot 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: > > 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 >