[syzbot] WARNING in cpuset_write_resmask

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: ea586a076e8a Add linux-next specific files for 20211224
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=15677063b00000
kernel config: https://syzkaller.appspot.com/x/.config?x=a9c4e3dde2c568fb
dashboard link: https://syzkaller.appspot.com/bug?extid=568dc81cd20b72d4a49f
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+568dc8...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 0 PID: 5329 at kernel/cgroup/cpuset.c:1817 update_nodemasks_hier kernel/cgroup/cpuset.c:1817 [inline]
WARNING: CPU: 0 PID: 5329 at kernel/cgroup/cpuset.c:1817 update_nodemask kernel/cgroup/cpuset.c:1890 [inline]
WARNING: CPU: 0 PID: 5329 at kernel/cgroup/cpuset.c:1817 cpuset_write_resmask+0x167b/0x20f0 kernel/cgroup/cpuset.c:2457
Modules linked in:
CPU: 0 PID: 5329 Comm: syz-executor.3 Not tainted 5.16.0-rc6-next-20211224-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:update_nodemasks_hier kernel/cgroup/cpuset.c:1817 [inline]
RIP: 0010:update_nodemask kernel/cgroup/cpuset.c:1890 [inline]
RIP: 0010:cpuset_write_resmask+0x167b/0x20f0 kernel/cgroup/cpuset.c:2457
Code: 3c 08 00 0f 85 ed 08 00 00 49 8b 9c 24 38 01 00 00 48 89 ef 48 89 de e8 53 4a 04 00 48 39 dd 0f 84 dd ef ff ff e8 d5 46 04 00 <0f> 0b e9 d1 ef ff ff e8 c9 46 04 00 e8 34 9d ef ff e8 bf 46 04 00
RSP: 0018:ffffc900094af970 EFLAGS: 00010212
RAX: 0000000000003f9c RBX: 0000000000000001 RCX: ffffc90003eba000
RDX: 0000000000040000 RSI: ffffffff8173bdab RDI: 0000000000000003
RBP: 0000000000000003 R08: 0000000000000003 R09: ffffffff8ffb5957
R10: ffffffff8173bd9d R11: 0000000000000001 R12: ffff88807c37f800
R13: ffff88807c37f854 R14: ffff88807c37f938 R15: 0000000000000000
FS: 00007fa6a243a700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5868fc51b8 CR3: 000000003c8a6000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
cgroup_file_write+0x1ec/0x780 kernel/cgroup/cgroup.c:3853
kernfs_fop_write_iter+0x342/0x500 fs/kernfs/file.c:296
call_write_iter include/linux/fs.h:2079 [inline]
do_iter_readv_writev+0x47a/0x750 fs/read_write.c:725
do_iter_write+0x188/0x710 fs/read_write.c:851
vfs_writev+0x1aa/0x630 fs/read_write.c:924
do_writev+0x139/0x300 fs/read_write.c:967
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fa6a3ac4e99
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa6a243a168 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007fa6a3bd7f60 RCX: 00007fa6a3ac4e99
RDX: 0000000000000008 RSI: 0000000020000040 RDI: 0000000000000005
RBP: 00007fa6a3b1eff1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd7ace88ff R14: 00007fa6a243a300 R15: 0000000000022000
</TASK>


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: e5313968c41b Merge branch 'Split bpf_sk_lookup remote_port..
git tree: bpf-next
console output: https://syzkaller.appspot.com/x/log.txt?x=113aeefa700000
kernel config: https://syzkaller.appspot.com/x/.config?x=c40b67275bfe2a58

dashboard link: https://syzkaller.appspot.com/bug?extid=568dc81cd20b72d4a49f
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13bb97ce700000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12062c8e700000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+568dc8...@syzkaller.appspotmail.com

------------[ cut here ]------------

WARNING: CPU: 1 PID: 3647 at kernel/cgroup/cpuset.c:1817 update_nodemasks_hier kernel/cgroup/cpuset.c:1817 [inline]
WARNING: CPU: 1 PID: 3647 at kernel/cgroup/cpuset.c:1817 update_nodemask kernel/cgroup/cpuset.c:1890 [inline]
WARNING: CPU: 1 PID: 3647 at kernel/cgroup/cpuset.c:1817 cpuset_write_resmask+0x167b/0x20f0 kernel/cgroup/cpuset.c:2457
Modules linked in:
CPU: 0 PID: 3647 Comm: syz-executor287 Not tainted 5.16.0-syzkaller-11655-ge5313968c41b #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:update_nodemasks_hier kernel/cgroup/cpuset.c:1817 [inline]
RIP: 0010:update_nodemask kernel/cgroup/cpuset.c:1890 [inline]
RIP: 0010:cpuset_write_resmask+0x167b/0x20f0 kernel/cgroup/cpuset.c:2457

Code: 3c 08 00 0f 85 ed 08 00 00 49 8b 9c 24 38 01 00 00 48 89 ef 48 89 de e8 63 4a 04 00 48 39 dd 0f 84 dd ef ff ff e8 e5 46 04 00 <0f> 0b e9 d1 ef ff ff e8 d9 46 04 00 e8 b4 a5 ef ff e8 cf 46 04 00
RSP: 0018:ffffc90003acfb18 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000
RDX: ffff88801e193a00 RSI: ffffffff81740f0b RDI: 0000000000000003
RBP: 0000000000000003 R08: 0000000000000003 R09: ffffffff8fdeca17
R10: ffffffff81740efd R11: 0000000000000001 R12: ffff888074f2e000
R13: ffff888074f2e054 R14: ffff888074f2e138 R15: 0000000000000000
FS: 00007fee62f33700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007ffcf8240960 CR3: 0000000072ae3000 CR4: 00000000003506f0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>

cgroup_file_write+0x1de/0x760 kernel/cgroup/cgroup.c:3877
kernfs_fop_write_iter+0x342/0x500 fs/kernfs/file.c:296
call_write_iter include/linux/fs.h:2086 [inline]
new_sync_write+0x431/0x660 fs/read_write.c:503
vfs_write+0x7cd/0xae0 fs/read_write.c:590
ksys_write+0x12d/0x250 fs/read_write.c:643

do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae

RIP: 0033:0x7fee62f82b79
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 15 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fee62f33308 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fee6300c4c8 RCX: 00007fee62f82b79
RDX: 0000000000000001 RSI: 0000000020000080 RDI: 0000000000000006
RBP: 00007fee6300c4c0 R08: 0000000000000012 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fee6300c4cc
R13: 00007fee62fd92b0 R14: 6d2e746573757063 R15: 0000000000022000
</TASK>

[syzbot]

syzbot has bisected this issue to:

commit e4b8954074f6d0db01c8c97d338a67f9389c042f
Author: Eric Dumazet <edum...@google.com>
Date: Tue Dec 7 01:30:37 2021 +0000

netlink: add net device refcount tracker to struct ethnl_req_info

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=15c42532700000
start commit: e5313968c41b Merge branch 'Split bpf_sk_lookup remote_port..
git tree: bpf-next
final oops: https://syzkaller.appspot.com/x/report.txt?x=17c42532700000
console output: https://syzkaller.appspot.com/x/log.txt?x=13c42532700000

kernel config: https://syzkaller.appspot.com/x/.config?x=c40b67275bfe2a58
dashboard link: https://syzkaller.appspot.com/bug?extid=568dc81cd20b72d4a49f

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13bb97ce700000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12062c8e700000

Reported-by: syzbot+568dc8...@syzkaller.appspotmail.com
Fixes: e4b8954074f6 ("netlink: add net device refcount tracker to struct ethnl_req_info")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

[Tejun Heo]

(cc'ing Waiman and quoting whole body)

Hello, Waiman.

It looks like it's hitting

WARN_ON(!is_in_v2_mode() && !nodes_equal(cp->mems_allowed, cp->effective_mems))

Can you take a look?

Thanks.

--
tejun

[Waiman Long]

On 2/22/22 12:26, Tejun Heo wrote:
> (cc'ing Waiman and quoting whole body)
>
> Hello, Waiman.
>
> It looks like it's hitting
>
> WARN_ON(!is_in_v2_mode() && !nodes_equal(cp->mems_allowed, cp->effective_mems))
>
> Can you take a look?

Sure. I will take a look at that.

Cheers,
Longman

[Waiman Long]

On 2/22/22 12:26, Tejun Heo wrote:

> (cc'ing Waiman and quoting whole body)
>
> Hello, Waiman.
>
> It looks like it's hitting
>
> WARN_ON(!is_in_v2_mode() && !nodes_equal(cp->mems_allowed, cp->effective_mems))
>
> Can you take a look?

My preliminary analysis is that the warning may be caused by my commit
1f1562fcd04a ("cgroup/cpuset: Don't let child cpusets restrict parent in
default hierarchy") since the merge branch e5313968c41b is missing the
fix commit d068eebbd482 ("cgroup/cpuset: Make child cpusets restrict
parents on v1 hierarchy"). I believe the problem should be gone once the
merge branch is updated to a later upstream baseline.

Cheers,
Longman

[Tejun Heo]

On Tue, Feb 22, 2022 at 01:22:13PM -0500, Waiman Long wrote:
> My preliminary analysis is that the warning may be caused by my commit
> 1f1562fcd04a ("cgroup/cpuset: Don't let child cpusets restrict parent in
> default hierarchy") since the merge branch e5313968c41b is missing the fix
> commit d068eebbd482 ("cgroup/cpuset: Make child cpusets restrict parents on
> v1 hierarchy"). I believe the problem should be gone once the merge branch
> is updated to a later upstream baseline.

Fantastic. Thank you so much for taking a look.

--
tejun

[syzbot]

syzbot suspects this issue was fixed by commit:

commit d068eebbd4822b6c14a7ea375dfe53ca5c69c776
Author: Michal Koutný <mko...@suse.com>
Date: Fri Dec 17 15:48:54 2021 +0000

cgroup/cpuset: Make child cpusets restrict parents on v1 hierarchy

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=142f17f7700000
start commit: e5313968c41b Merge branch 'Split bpf_sk_lookup remote_port..
git tree: bpf-next

kernel config: https://syzkaller.appspot.com/x/.config?x=c40b67275bfe2a58
dashboard link: https://syzkaller.appspot.com/bug?extid=568dc81cd20b72d4a49f

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13bb97ce700000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12062c8e700000

If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: cgroup/cpuset: Make child cpusets restrict parents on v1 hierarchy

[Dmitry Vyukov]

Based on commit subject looks reasonable: