general protection fault in __bfs (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 9d5c0b3a8e1a Linux 4.14.295
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=15fba244880000
kernel config: https://syzkaller.appspot.com/x/.config?x=746c079015a92425
dashboard link: https://syzkaller.appspot.com/bug?extid=105f44d0574afa3585e2
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=123188b4880000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1214931a880000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ed6fcf5895a2/disk-9d5c0b3a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/341aa3534116/vmlinux-9d5c0b3a.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/35d4cdce895e/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+105f44...@syzkaller.appspotmail.com

kasan: CONFIG_KASAN_INLINE enabled
NILFS (loop0): segctord starting. Construction interval = 5 seconds, CP frequency < 30 seconds
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 1 PID: 7959 Comm: syz-executor106 Not tainted 4.14.295-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
task: ffff8880b48f8640 task.stack: ffff8880963b0000
RIP: 0010:lock_accessed kernel/locking/lockdep.c:979 [inline]
RIP: 0010:__bfs.part.0+0x20e/0x470 kernel/locking/lockdep.c:1045
RSP: 0018:ffff8880963b7370 EFLAGS: 00010007
RAX: 0000000001d0dd96 RBX: ffffffff8bc82250 RCX: 0000000000000000
RDX: 0000000000000002 RSI: 0000000000000000 RDI: 0000000000000010
RBP: ffff8880963b7428 R08: 0000000000000000 R09: 0000000000001c0e
R10: 0000000000000002 R11: 0000000000000001 R12: ffffffff8140f610
R13: 0000000000000000 R14: 0000000000000000 R15: dffffc0000000000
FS: 0000555557184300(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000144 CR3: 00000000a92a6000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
__bfs kernel/locking/lockdep.c:1424 [inline]
__bfs_backwards kernel/locking/lockdep.c:1082 [inline]
find_usage_backwards kernel/locking/lockdep.c:1424 [inline]
check_usage_backwards+0x167/0x2c0 kernel/locking/lockdep.c:2713
mark_lock_irq kernel/locking/lockdep.c:2804 [inline]
mark_lock+0x3c7/0x1050 kernel/locking/lockdep.c:3194
mark_irqflags kernel/locking/lockdep.c:3078 [inline]
__lock_acquire+0x594/0x3f20 kernel/locking/lockdep.c:3448
lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998
down_read+0x36/0x80 kernel/locking/rwsem.c:24
nilfs_bmap_lookup_at_level+0x6b/0x380 fs/nilfs2/bmap.c:77
nilfs_bmap_lookup fs/nilfs2/bmap.h:179 [inline]
nilfs_mdt_submit_block.constprop.0+0x152/0x970 fs/nilfs2/mdt.c:151
nilfs_mdt_read_block+0x7c/0x320 fs/nilfs2/mdt.c:184
nilfs_mdt_get_block+0xc7/0xb90 fs/nilfs2/mdt.c:259
nilfs_palloc_get_block+0xb2/0x250 fs/nilfs2/alloc.c:225
nilfs_palloc_get_entry_block+0x17d/0x230 fs/nilfs2/alloc.c:327
nilfs_ifile_get_inode_block+0xb4/0x150 fs/nilfs2/ifile.c:152
__nilfs_read_inode fs/nilfs2/inode.c:492 [inline]
nilfs_iget+0x1c2/0x810 fs/nilfs2/inode.c:601
nilfs_get_root_dentry+0x24/0x1f0 fs/nilfs2/super.c:918
nilfs_fill_super fs/nilfs2/super.c:1092 [inline]
nilfs_mount+0x984/0xd00 fs/nilfs2/super.c:1331
mount_fs+0x92/0x2a0 fs/super.c:1237
vfs_kern_mount.part.0+0x5b/0x470 fs/namespace.c:1046
vfs_kern_mount fs/namespace.c:1036 [inline]
do_new_mount fs/namespace.c:2572 [inline]
do_mount+0xe65/0x2a30 fs/namespace.c:2905
SYSC_mount fs/namespace.c:3121 [inline]
SyS_mount+0xa8/0x120 fs/namespace.c:3098
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7f5b3cecd55a
RSP: 002b:00007ffc1e9af8e8 EFLAGS: 00000286 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f5b3cecd55a
RDX: 0000000020000140 RSI: 0000000020000100 RDI: 00007ffc1e9af900
RBP: 00007ffc1e9af900 R08: 00007ffc1e9af940 R09: 00005555571842c0
R10: 0000000000000000 R11: 0000000000000286 R12: 0000000000000004
R13: 00007ffc1e9af940 R14: 000000000000003a R15: 0000000020000770
Code: 78 01 00 00 4d 8b 36 4c 39 f3 74 78 49 8d 7e 10 4c 89 f0 4c 8b 0d a3 69 a7 0a 48 89 fa 48 2d 60 9a c8 8b 48 c1 ea 03 48 c1 f8 06 <42> 80 3c 3a 00 0f 85 28 01 00 00 49 8b 4e 10 4c 8d 41 2c 4c 89
RIP: lock_accessed kernel/locking/lockdep.c:979 [inline] RSP: ffff8880963b7370
RIP: __bfs.part.0+0x20e/0x470 kernel/locking/lockdep.c:1045 RSP: ffff8880963b7370
---[ end trace ed54b10684919e04 ]---
----------------
Code disassembly (best guess):
0: 78 01 js 0x3
2: 00 00 add %al,(%rax)
4: 4d 8b 36 mov (%r14),%r14
7: 4c 39 f3 cmp %r14,%rbx
a: 74 78 je 0x84
c: 49 8d 7e 10 lea 0x10(%r14),%rdi
10: 4c 89 f0 mov %r14,%rax
13: 4c 8b 0d a3 69 a7 0a mov 0xaa769a3(%rip),%r9 # 0xaa769bd
1a: 48 89 fa mov %rdi,%rdx
1d: 48 2d 60 9a c8 8b sub $0xffffffff8bc89a60,%rax
23: 48 c1 ea 03 shr $0x3,%rdx
27: 48 c1 f8 06 sar $0x6,%rax
* 2b: 42 80 3c 3a 00 cmpb $0x0,(%rdx,%r15,1) <-- trapping instruction
30: 0f 85 28 01 00 00 jne 0x15e
36: 49 8b 4e 10 mov 0x10(%r14),%rcx
3a: 4c 8d 41 2c lea 0x2c(%rcx),%r8
3e: 4c rex.WR
3f: 89 .byte 0x89


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