[syzbot] WARNING in ep_poll (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 6d464646530f Merge branch 'for-next/core' into for-kernelci
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=10905dbb880000
kernel config: https://syzkaller.appspot.com/x/.config?x=23eec5c79c22aaf8
dashboard link: https://syzkaller.appspot.com/bug?extid=040b317810fd3e21b55d
compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=110f4605880000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14ba453d880000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f22d29413625/disk-6d464646.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/389f0a5f1a4a/vmlinux-6d464646.xz
kernel image: https://storage.googleapis.com/syzbot-assets/48ddb02d82da/Image-6d464646.gz.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/ba54b6200826/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+040b31...@syzkaller.appspotmail.com

------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(lock->magic != lock)
WARNING: CPU: 1 PID: 3083 at kernel/locking/mutex.c:582 __mutex_lock_common+0x4c4/0xca8 kernel/locking/mutex.c:582
Modules linked in:
CPU: 1 PID: 3083 Comm: udevd Not tainted 6.1.0-rc6-syzkaller-32662-g6d464646530f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/30/2022
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : __mutex_lock_common+0x4c4/0xca8 kernel/locking/mutex.c:582
lr : __mutex_lock_common+0x4c4/0xca8 kernel/locking/mutex.c:582
sp : ffff80000ffabb30
x29: ffff80000ffabba0 x28: ffff80000eec8000 x27: ffff0000c9ac9b40

x26: 0000000000000000
x25: ffff0000c9289a40
x24: 0000000000000002

x23: ffff80000866ba78
x22: 0000000000000000
x21: 0000000000000000

x20: 0000000000000000
x19: ffff0000c9ac9a00
x18: 000000000000031c

x17: ffff80000c0cd83c
x16: 0000000000000000
x15: 0000000000000000

x14: 0000000000000000
x13: 0000000000000012 x12: ffff80000d93b3d0

x11: ff808000081c4d40
x10: 0000000000000000
x9 : c0fb5fb0435d7400

x8 : c0fb5fb0435d7400
x7 : 4e5241575f534b43
x6 : ffff80000c08e4f4

x5 : 0000000000000000
x4 : 0000000000000001
x3 : 0000000000000000

x2 : 0000000000000000
x1 : 0000000100000000
x0 : 0000000000000028

Call trace:
__mutex_lock_common+0x4c4/0xca8 kernel/locking/mutex.c:582
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
ep_send_events fs/eventpoll.c:1655 [inline]
ep_poll+0x320/0xc70 fs/eventpoll.c:1821
do_epoll_wait+0x144/0x18c fs/eventpoll.c:2256
do_epoll_pwait fs/eventpoll.c:2290 [inline]
__do_sys_epoll_pwait+0x110/0x214 fs/eventpoll.c:2303
__se_sys_epoll_pwait fs/eventpoll.c:2297 [inline]
__arm64_sys_epoll_pwait+0x30/0x40 fs/eventpoll.c:2297
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall arch/arm64/kernel/syscall.c:52 [inline]
el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x48/0x164 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:584
irq event stamp: 121585
hardirqs last enabled at (121585): [<ffff8000080387b0>] local_daif_restore arch/arm64/include/asm/daifflags.h:75 [inline]
hardirqs last enabled at (121585): [<ffff8000080387b0>] el0_svc_common+0x40/0x220 arch/arm64/kernel/syscall.c:107
hardirqs last disabled at (121584): [<ffff80000c080d24>] el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
softirqs last enabled at (121232): [<ffff80000801c38c>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32
softirqs last disabled at (121230): [<ffff80000801c358>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19
---[ end trace 0000000000000000 ]---


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[syzbot]

Auto-closing this bug as obsolete.
No recent activity, existing reproducers are no longer triggering the issue.