* Re: [syzbot] [mm?] WARNING in set_mm_walk
[not found] <6a7a6929.b50370da.49fe0.005e.GAE@google.com>
@ 2026-08-12 12:26 ` syzbot
2026-08-12 21:03 ` Andrew Morton
0 siblings, 1 reply; 3+ messages in thread
From: syzbot @ 2026-08-12 12:26 UTC (permalink / raw)
To: akpm, axelrasmussen, baohua, baolin.wang, cgroups, david, hannes,
kasong, kernel-team, linux-kernel, linux-mm, ljs, mhocko, mhocko,
muchun.song, qi.zheng, roman.gushchin, shakeel.butt,
syzkaller-bugs, weixugc, yuanchu
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
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>
---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [syzbot] [mm?] WARNING in set_mm_walk
2026-08-12 12:26 ` [syzbot] [mm?] WARNING in set_mm_walk syzbot
@ 2026-08-12 21:03 ` Andrew Morton
2026-08-12 21:41 ` Shakeel Butt
0 siblings, 1 reply; 3+ messages in thread
From: Andrew Morton @ 2026-08-12 21:03 UTC (permalink / raw)
To: syzbot
Cc: axelrasmussen, baohua, baolin.wang, cgroups, david, hannes,
kasong, kernel-team, linux-kernel, linux-mm, ljs, mhocko, mhocko,
muchun.song, qi.zheng, roman.gushchin, shakeel.butt,
syzkaller-bugs, weixugc, yuanchu
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>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [syzbot] [mm?] WARNING in set_mm_walk
2026-08-12 21:03 ` Andrew Morton
@ 2026-08-12 21:41 ` Shakeel Butt
0 siblings, 0 replies; 3+ messages in thread
From: Shakeel Butt @ 2026-08-12 21:41 UTC (permalink / raw)
To: Andrew Morton
Cc: syzbot, axelrasmussen, baohua, baolin.wang, cgroups, david,
hannes, kasong, kernel-team, linux-kernel, linux-mm, ljs, mhocko,
mhocko, muchun.song, qi.zheng, roman.gushchin, syzkaller-bugs,
weixugc, yuanchu
On Wed, Aug 12, 2026 at 02:03:58PM -0700, Andrew Morton wrote:
> 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?
>
Actually the first patch [1] of the series will fix this warning and we can
backport just that patch to the older stable kernels.
Do you want me to send that patch as a standalone?
[1] https://lore.kernel.org/all/20260811203203.3456029-2-shakeel.butt@linux.dev/
^ permalink raw reply [flat|nested] 3+ messages in thread
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[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
2026-08-12 21:41 ` Shakeel Butt
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