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AJvYcCXIF4EczKn2LKl62rmSEn04H8BaY8jkqhV/cqJeFd3cRyeZWIYQ1wl9Ma/ypUWL8bSB46UgRY1aHg==@kvack.org X-Gm-Message-State: AOJu0YyShiDgbdiNFu/go+1Qhspw6I3ZRQPKGJcWBlC55/OD3U3WIntE 1yBpYz41TxouCu8XM9An9zJgHxg1FxUilnTJANBk/8pwGdMmC9zm7ZQTIbfbOqOI3wnZYo6Fnid wIMDneEo3z0BkunBrB+E5RMaW99nK6Eo= X-Gm-Gg: AY/fxX42vUwrv0zI+q7v89Q8yNnjYEBUAHJTjN4MI+UvVXOMtJxQeu1GtV3i5HsgUF9 jegh0GeaCQPb0xdo8V3oYwV6m4mHwoXQBoBNuaSwzUwcjUfBUpeW2ZO6mgL09PP0Z8WXrOzDVnx gu51Eo0XR8Y8cAo+As7lSSww8Pg9Dzdv+htN04+i0anovyJC8sbflfotv8X6NemaMhK03Gc1XrK lT8kDpidTq3gf5nQAQZzxWdLG2eG3zJ5YT4z81FmxSxgrEkdO46z7/FEGVWd6S+BoVd/n1BGzwX XHyZnR60ZzHf9itBRjCD3P3ndBG4WkhSe0odFwG4NQDoZx6KQaKpJ22xk0cYdVk4+HEJ3+0= X-Received: by 2002:a05:690e:1651:b0:644:2e5b:4124 with SMTP id 956f58d0204a3-6491649f516mr5984846d50.25.1768719716078; Sat, 17 Jan 2026 23:01:56 -0800 (PST) MIME-Version: 1.0 References: <696b56b1.050a0220.3390f1.0007.GAE@google.com> <20260117165722.6dc25d72fd58254cb89e711b@linux-foundation.org> In-Reply-To: From: Deepanshu Kartikey Date: Sun, 18 Jan 2026 12:31:43 +0530 X-Gm-Features: AZwV_Qg0s-Fmk0LdSiYD_syYS5grst0M2xrOlSOhhy_fgxLE0lSLFhW8_tjzxJs Message-ID: Subject: Re: [syzbot] [cgroups?] [mm?] WARNING in memcg1_swapout To: Andrew Morton Cc: syzbot , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mhocko@kernel.org, roman.gushchin@linux.dev, shakeel.butt@linux.dev, syzkaller-bugs@googlegroups.com, Johannes Weiner , Muchun Song , Minchan Kim Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 1F2B1C000C X-Stat-Signature: pijef3m1fy6jgtm93bua8umttpdbz9ik X-Rspam-User: X-HE-Tag: 1768719716-976601 X-HE-Meta: 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 /13sTPjw 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 IYHRtmQc XRzasgyHV84iV91KxjUhCgGGflFNkCvTsFl6CTChGeDRUMhIQSvSfGmNDRQX05xE3vdk5gZBlwJcXNXye0gblTJWhxiSZDVgsLgfd0YrXfEgWIY5xvZGC/XWdg0zohyALVKaz+gM/Ac= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Sun, Jan 18, 2026 at 9:51=E2=80=AFAM Deepanshu Kartikey wrote: > > On Sun, Jan 18, 2026 at 6:27=E2=80=AFAM Andrew Morton wrote: > > > > On Sat, 17 Jan 2026 01:30:25 -0800 syzbot wrote: > > > > > Hello, > > > > > > syzbot found the following issue on: > > > > > > HEAD commit: 0f853ca2a798 Add linux-next specific files for 202601= 13 > > > git tree: linux-next > > > console output: https://syzkaller.appspot.com/x/log.txt?x=3D14f7259a5= 80000 > > > kernel config: https://syzkaller.appspot.com/x/.config?x=3D8d6e5303d= 96e21b5 > > > dashboard link: https://syzkaller.appspot.com/bug?extid=3D079a3b213ad= d54dd18a7 > > > compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909= b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 > > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=3D167ef92= 2580000 > > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=3D16d295fa5= 80000 > > > > > > Downloadable assets: > > > disk image: https://storage.googleapis.com/syzbot-assets/480cd223f3f6= /disk-0f853ca2.raw.xz > > > vmlinux: https://storage.googleapis.com/syzbot-assets/1ca2f0dbb7cc/vm= linux-0f853ca2.xz > > > kernel image: https://storage.googleapis.com/syzbot-assets/60a0fef580= 5b/bzImage-0f853ca2.xz > > > > > > IMPORTANT: if you fix the issue, please add the following tag to the = commit: > > > Reported-by: syzbot+079a3b213add54dd18a7@syzkaller.appspotmail.com > > > > Thanks. > > > > > ------------[ cut here ]------------ > > > WARNING: mm/memcontrol-v1.c:642 at memcg1_swapout+0x6c2/0x8d0 mm/memc= ontrol-v1.c:642, CPU#0: syz.4.233/6746 > > > > That's > > > > VM_WARN_ON_ONCE(oldid !=3D 0); > > > > which was added by Deepanshu's "mm/swap_cgroup: fix kernel BUG in > > swap_cgroup_record". > > > > This patch has Fixes: 1a4e58cce84e ("mm: introduce MADV_PAGEOUT"), > > which is six years old. For some reason it has no cc:stable. > > > > Deepanshu's patch has no reviews. > > > > So can I please do the memcg maintainer summoning dance here? We have = a > > repeatable BUG happening in mainline Linux. > > > > Hi Andrew, > > I checked the git blame output for commit 0f853ca2a798: > > Line 763: memcg1_swapout(folio, swap); > Line 764: __swap_cache_del_folio(ci, folio, swap, shadow); > (d7a7b2f91f36b - Kairui Song, 2026-01-13 02:33:36 +08= 00) > > Kairui's reordering patch appears to have been merged on Jan 13. > The syzbot report is also from Jan 13, likely from earlier in the > day before the reordering patch was merged. > > So this report is from before the fix. The warning should not appear > in linux-next builds after Jan 13. > > Thanks, > > Deepanshu Hi Andrew, I tested with the latest linux-next in sysbot. It is working fine Thanks Deepanshu