WARNING in __bfs (4)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3f8a27f9e27b Linux 4.19.211
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14734752700000
kernel config: https://syzkaller.appspot.com/x/.config?x=9b9277b418617afe
dashboard link: https://syzkaller.appspot.com/bug?extid=0d5cbccb26b9e1a48531
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)

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+0d5cbc...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 0 PID: 32514 at kernel/locking/lockdep.c:966 lock_accessed kernel/locking/lockdep.c:966 [inline]
WARNING: CPU: 0 PID: 32514 at kernel/locking/lockdep.c:966 __bfs.part.0.cold+0x11/0xeb kernel/locking/lockdep.c:1033
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 32514 Comm: kworker/0:3 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events l2cap_chan_timeout
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
panic+0x26a/0x50e kernel/panic.c:186
__warn.cold+0x20/0x5a kernel/panic.c:541
report_bug+0x262/0x2b0 lib/bug.c:183
fixup_bug arch/x86/kernel/traps.c:178 [inline]
fixup_bug arch/x86/kernel/traps.c:173 [inline]
do_error_trap+0x1d7/0x310 arch/x86/kernel/traps.c:296
invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:1038
RIP: 0010:lock_accessed kernel/locking/lockdep.c:966 [inline]
RIP: 0010:__bfs.part.0.cold+0x11/0xeb kernel/locking/lockdep.c:1033
Code: 60 37 24 8d e8 bc 32 a5 f9 eb 88 48 c7 c7 40 f7 36 8d e8 ae 32 a5 f9 eb bd 48 c7 c7 60 1d 6a 88 48 89 54 24 20 e8 a6 87 00 00 <0f> 0b 49 8d 46 10 48 8b 54 24 20 48 89 44 24 18 48 c1 e8 03 42 80
RSP: 0018:ffff88800f7af770 EFLAGS: 00010086
RAX: 0000000000000024 RBX: ffffffff8ceff260 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff814dff01 RDI: ffffed1001ef5ee0
RBP: ffff88800f7af828 R08: 0000000000000024 R09: 0000000000000000
R10: 0000000000000005 R11: ffffffff8c66501b R12: ffffffff814a7290
R13: 0000000000000000 R14: 0000000000000000 R15: dffffc0000000000
__bfs kernel/locking/lockdep.c:1388 [inline]
__bfs_backwards kernel/locking/lockdep.c:1070 [inline]
find_usage_backwards kernel/locking/lockdep.c:1388 [inline]
check_usage_backwards+0x17a/0x300 kernel/locking/lockdep.c:2669
mark_lock_irq kernel/locking/lockdep.c:2760 [inline]
mark_lock+0x3d8/0x1160 kernel/locking/lockdep.c:3132
mark_irqflags kernel/locking/lockdep.c:3024 [inline]
__lock_acquire+0x63f/0x3ff0 kernel/locking/lockdep.c:3373
lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
_raw_spin_lock_bh+0x2f/0x40 kernel/locking/spinlock.c:168
spin_lock_bh include/linux/spinlock.h:334 [inline]
lock_sock_nested+0x3b/0x110 net/core/sock.c:2884
l2cap_sock_teardown_cb+0xa0/0x6d0 net/bluetooth/l2cap_sock.c:1348
l2cap_chan_del+0xbc/0xa50 net/bluetooth/l2cap_core.c:603
l2cap_chan_close+0x1b5/0x950 net/bluetooth/l2cap_core.c:761
l2cap_chan_timeout+0x17e/0x2f0 net/bluetooth/l2cap_core.c:430
process_one_work+0x864/0x1570 kernel/workqueue.c:2153
worker_thread+0x64c/0x1130 kernel/workqueue.c:2296
kthread+0x33f/0x460 kernel/kthread.c:259
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
Shutting down cpus with NMI
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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syzbot will keep track of this issue. See:
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 3f8a27f9e27b Linux 4.19.211
git tree: linux-4.19.y

console output: https://syzkaller.appspot.com/x/log.txt?x=16288906880000

kernel config: https://syzkaller.appspot.com/x/.config?x=9b9277b418617afe
dashboard link: https://syzkaller.appspot.com/bug?extid=0d5cbccb26b9e1a48531
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=120eda06880000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12c9f49a880000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/98c0bdb4abb3/disk-3f8a27f9.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ea228ff02669/vmlinux-3f8a27f9.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/d3c9810d7dca/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0d5cbc...@syzkaller.appspotmail.com

NILFS (loop0): segctord starting. Construction interval = 5 seconds, CP frequency < 30 seconds
------------[ cut here ]------------
WARNING: CPU: 1 PID: 8098 at kernel/locking/lockdep.c:966 lock_accessed kernel/locking/lockdep.c:966 [inline]
WARNING: CPU: 1 PID: 8098 at kernel/locking/lockdep.c:966 __bfs.part.0.cold+0x11/0xeb kernel/locking/lockdep.c:1033

Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 8098 Comm: syz-executor300 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022

Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
panic+0x26a/0x50e kernel/panic.c:186
__warn.cold+0x20/0x5a kernel/panic.c:541
report_bug+0x262/0x2b0 lib/bug.c:183
fixup_bug arch/x86/kernel/traps.c:178 [inline]
fixup_bug arch/x86/kernel/traps.c:173 [inline]
do_error_trap+0x1d7/0x310 arch/x86/kernel/traps.c:296
invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:1038
RIP: 0010:lock_accessed kernel/locking/lockdep.c:966 [inline]
RIP: 0010:__bfs.part.0.cold+0x11/0xeb kernel/locking/lockdep.c:1033
Code: 60 37 24 8d e8 bc 32 a5 f9 eb 88 48 c7 c7 40 f7 36 8d e8 ae 32 a5 f9 eb bd 48 c7 c7 60 1d 6a 88 48 89 54 24 20 e8 a6 87 00 00 <0f> 0b 49 8d 46 10 48 8b 54 24 20 48 89 44 24 18 48 c1 e8 03 42 80

RSP: 0018:ffff888092007238 EFLAGS: 00010086
RAX: 0000000000000024 RBX: ffffffff8cf7e0d0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff814dff01 RDI: ffffed1012400e39
RBP: ffff8880920072f0 R08: 0000000000000024 R09: 0000000000000000
R10: 0000000000000005 R11: ffffffff8c66505b R12: ffffffff814a7290

R13: 0000000000000000 R14: 0000000000000000 R15: dffffc0000000000
__bfs kernel/locking/lockdep.c:1388 [inline]
__bfs_backwards kernel/locking/lockdep.c:1070 [inline]
find_usage_backwards kernel/locking/lockdep.c:1388 [inline]
check_usage_backwards+0x17a/0x300 kernel/locking/lockdep.c:2669
mark_lock_irq kernel/locking/lockdep.c:2760 [inline]
mark_lock+0x3d8/0x1160 kernel/locking/lockdep.c:3132

mark_irqflags kernel/locking/lockdep.c:3016 [inline]
__lock_acquire+0x5cb/0x3ff0 kernel/locking/lockdep.c:3373
lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908
down_read+0x36/0x80 kernel/locking/rwsem.c:24
nilfs_bmap_lookup_at_level+0x7b/0x3e0 fs/nilfs2/bmap.c:68
nilfs_bmap_lookup fs/nilfs2/bmap.h:170 [inline]
nilfs_mdt_submit_block.constprop.0+0x1a5/0xaa0 fs/nilfs2/mdt.c:142
nilfs_mdt_read_block+0x96/0x3e0 fs/nilfs2/mdt.c:175
nilfs_mdt_get_block+0xe6/0xd40 fs/nilfs2/mdt.c:250
nilfs_palloc_get_block+0xc4/0x2b0 fs/nilfs2/alloc.c:216
nilfs_palloc_get_entry_block+0x17b/0x230 fs/nilfs2/alloc.c:318
nilfs_ifile_get_inode_block+0xbf/0x170 fs/nilfs2/ifile.c:143
__nilfs_read_inode fs/nilfs2/inode.c:483 [inline]
nilfs_iget+0x204/0x860 fs/nilfs2/inode.c:592
nilfs_get_root_dentry+0x26/0x250 fs/nilfs2/super.c:908
nilfs_fill_super fs/nilfs2/super.c:1082 [inline]
nilfs_mount+0xac8/0xe70 fs/nilfs2/super.c:1321
mount_fs+0xa3/0x310 fs/super.c:1261
vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961
vfs_kern_mount fs/namespace.c:951 [inline]
do_new_mount fs/namespace.c:2492 [inline]
do_mount+0x115c/0x2f50 fs/namespace.c:2822
ksys_mount+0xcf/0x130 fs/namespace.c:3038
__do_sys_mount fs/namespace.c:3052 [inline]
__se_sys_mount fs/namespace.c:3049 [inline]
__x64_sys_mount+0xba/0x150 fs/namespace.c:3049
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fcc5afc76ba
Code: 83 c4 08 5b 5d c3 66 2e 0f 1f 84 00 00 00 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fffb859eff8 EFLAGS: 00000286 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fcc5afc76ba
RDX: 00000000200000c0 RSI: 0000000020000100 RDI: 00007fffb859f010
RBP: 00007fffb859f010 R08: 00007fffb859f050 R09: 00005555573a92c0
R10: 0000000000000000 R11: 0000000000000286 R12: 0000000000000004
R13: 00007fffb859f050 R14: 0000000000000039 R15: 0000000020000758