Subject: [syzbot] [net?] WARNING in pppol2tp_release

From: syzbot <[email-masked]>
Date: Mon, 05 Aug 2024 00:53:32 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    3608d6aca5e7 Merge branch 'dsa-en7581' into main
git tree:       net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=122d5b55980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=fbd68ab0b66eda34
dashboard link: https://syzkaller.appspot.com/bug?extid=0e85b10481d2f5478053
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9d523e471f71/disk-3608d6ac.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ed20c68f58d7/vmlinux-3608d6ac.xz
kernel image: https://storage.googleapis.com/syzbot-assets/320eb8606813/bzImage-3608d6ac.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]

------------[ cut here ]------------
WARNING: CPU: 1 PID: 5467 at kernel/workqueue.c:2259 __queue_work+0xcd3/0xf50 kernel/workqueue.c:2258
Modules linked in:
CPU: 1 UID: 0 PID: 5467 Comm: syz.3.43 Not tainted 6.11.0-rc1-syzkaller-00247-g3608d6aca5e7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
RIP: 0010:__queue_work+0xcd3/0xf50 kernel/workqueue.c:2258
Code: ff e8 11 84 36 00 90 0f 0b 90 e9 1e fd ff ff e8 03 84 36 00 eb 13 e8 fc 83 36 00 eb 0c e8 f5 83 36 00 eb 05 e8 ee 83 36 00 90 <0f> 0b 90 48 83 c4 60 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc
RSP: 0018:ffffc90004607b48 EFLAGS: 00010093
RAX: ffffffff815ce274 RBX: ffff8880661fda00 RCX: ffff8880661fda00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffff815cd6d4 R09: 0000000000000000
R10: ffffc90004607c20 R11: fffff520008c0f85 R12: ffff88802ac33800
R13: ffff88802ac339c0 R14: dffffc0000000000 R15: 0000000000000008
FS:  00005555713eb500(0000) GS:ffff8880b9300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000008 CR3: 000000001eda6000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 queue_work_on+0x1c2/0x380 kernel/workqueue.c:2392
 pppol2tp_release+0x163/0x230 net/l2tp/l2tp_ppp.c:445
 __sock_release net/socket.c:659 [inline]
 sock_close+0xbc/0x240 net/socket.c:1421
 __fput+0x24a/0x8a0 fs/file_table.c:422
 task_work_run+0x24f/0x310 kernel/task_work.c:228
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x168/0x370 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f061e9779f9
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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffff1c1fce8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 000000000001017d RCX: 00007f061e9779f9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007ffff1c1fdc0 R08: 0000000000000001 R09: 00007ffff1c1ffcf
R10: 00007f061e800000 R11: 0000000000000246 R12: 0000000000000032
R13: 00007ffff1c1fde0 R14: 00007ffff1c1fe00 R15: ffffffffffffffff
 </TASK>

---
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