kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 4250 Comm: kmmpd-loop4 Not tainted 5.4.210-syzkaller-00013-gdf2b5549c0ec #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
RIP: 0010:bdevname+0x2d/0x160 block/partition-generic.c:49
Code: 41 56 41 55 41 54 53 49 89 f6 48 89 fb 49 bc 00 00 00 00 00 fc ff df e8 81 6e 45 ff 48 8d bb 80 00 00 00 48 89 f8 48 c1 e8 03 <42> 80 3c 20 00 74 05 e8 97 d2 73 ff 4c 8b ab 80 00 00 00 48 83 c3
RSP: 0018:ffff8881e4c8fd88 EFLAGS: 00010202
RAX: 0000000000000010 RBX: 0000000000000000 RCX: ffff8881e2cdbf00
RDX: 0000000000000000 RSI: ffff8881ad9b9050 RDI: 0000000000000080
RBP: ffff8881e4c8ff00 R08: ffffffff81c8ab2f R09: ffffed103cd65c91
R10: ffffed103cd65c91 R11: 1ffff1103cd65c90 R12: dffffc0000000000
R13: 000000000000000a R14: ffff8881ad9b9050 R15: ffff8881ad9b9000
FS:  0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7002c51000 CR3: 00000001b4a9c000 CR4: 00000000003406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 kmmpd+0x225/0xa10 fs/ext4/mmp.c:158
 kthread+0x2d8/0x360 kernel/kthread.c:288
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352
Modules linked in:
---[ end trace f0f2d416356b3e28 ]---
RIP: 0010:bdevname+0x2d/0x160 block/partition-generic.c:49
Code: 41 56 41 55 41 54 53 49 89 f6 48 89 fb 49 bc 00 00 00 00 00 fc ff df e8 81 6e 45 ff 48 8d bb 80 00 00 00 48 89 f8 48 c1 e8 03 <42> 80 3c 20 00 74 05 e8 97 d2 73 ff 4c 8b ab 80 00 00 00 48 83 c3
RSP: 0018:ffff8881e4c8fd88 EFLAGS: 00010202
RAX: 0000000000000010 RBX: 0000000000000000 RCX: ffff8881e2cdbf00
RDX: 0000000000000000 RSI: ffff8881ad9b9050 RDI: 0000000000000080
RBP: ffff8881e4c8ff00 R08: ffffffff81c8ab2f R09: ffffed103cd65c91
R10: ffffed103cd65c91 R11: 1ffff1103cd65c90 R12: dffffc0000000000
R13: 000000000000000a R14: ffff8881ad9b9050 R15: ffff8881ad9b9000
FS:  0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd7d93bbb8 CR3: 00000001ef55d000 CR4: 00000000003406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	41 56                	push   %r14
   2:	41 55                	push   %r13
   4:	41 54                	push   %r12
   6:	53                   	push   %rbx
   7:	49 89 f6             	mov    %rsi,%r14
   a:	48 89 fb             	mov    %rdi,%rbx
   d:	49 bc 00 00 00 00 00 	movabs $0xdffffc0000000000,%r12
  14:	fc ff df
  17:	e8 81 6e 45 ff       	callq  0xff456e9d
  1c:	48 8d bb 80 00 00 00 	lea    0x80(%rbx),%rdi
  23:	48 89 f8             	mov    %rdi,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 20 00       	cmpb   $0x0,(%rax,%r12,1) <-- trapping instruction
  2f:	74 05                	je     0x36
  31:	e8 97 d2 73 ff       	callq  0xff73d2cd
  36:	4c 8b ab 80 00 00 00 	mov    0x80(%rbx),%r13
  3d:	48                   	rex.W
  3e:	83                   	.byte 0x83
  3f:	c3                   	retq