general protection fault, probably for non-canonical address 0xdffffc0000000008: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000040-0x0000000000000047]
CPU: 1 PID: 4397 Comm: syz.1.30 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:mtd_test_super+0xa4/0x1d0 drivers/mtd/mtdsuper.c:36
Code: 41 5c 41 5e 41 5f 5d c3 e8 49 8c 4d fc 43 80 3c 27 00 74 08 4c 89 f7 e8 fa bf 92 fc 4d 8b 36 49 8d 7e 40 48 89 f8 48 c1 e8 03 <42> 0f b6 04 20 84 c0 0f 85 cd 00 00 00 41 8b 6e 40 49 83 c6 38 4c
RSP: 0018:ffffc9000341fbd0 EFLAGS: 00010202
RAX: 0000000000000008 RBX: ffff888022486000 RCX: ffff88802c4f1dc0
RDX: 0000000000000000 RSI: ffff888022b1e000 RDI: 0000000000000040
RBP: dffffc0000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000683f70 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffff1100b2e282e
FS:  0000555561c85500(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9d95e50e20 CR3: 0000000077378000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 sget_fc+0x1f0/0x6f0 fs/super.c:548
 mtd_get_sb+0x5a/0x2b0 drivers/mtd/mtdsuper.c:65
 mtd_get_sb_by_nr drivers/mtd/mtdsuper.c:110 [inline]
 get_tree_mtd+0x4e2/0x760 drivers/mtd/mtdsuper.c:180
 romfs_get_tree+0x19/0x50 fs/romfs/super.c:560
 vfs_get_tree+0x88/0x270 fs/super.c:1541
 do_new_mount+0x247/0xa40 fs/namespace.c:3034
 do_mount fs/namespace.c:3377 [inline]
 __do_sys_mount fs/namespace.c:3585 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3562
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f9d95f7f159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd4bb39868 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f9d96206fa0 RCX: 00007f9d95f7f159
RDX: 00002000000002c0 RSI: 0000200000000200 RDI: 00002000000000c0
RBP: 00007f9d9601606b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000023000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9d96206fac R14: 00007f9d96206fa0 R15: 00007f9d96206fa0
 </TASK>
Modules linked in:
---[ end trace 5b7095dd906c99f8 ]---
RIP: 0010:mtd_test_super+0xa4/0x1d0 drivers/mtd/mtdsuper.c:36
Code: 41 5c 41 5e 41 5f 5d c3 e8 49 8c 4d fc 43 80 3c 27 00 74 08 4c 89 f7 e8 fa bf 92 fc 4d 8b 36 49 8d 7e 40 48 89 f8 48 c1 e8 03 <42> 0f b6 04 20 84 c0 0f 85 cd 00 00 00 41 8b 6e 40 49 83 c6 38 4c
RSP: 0018:ffffc9000341fbd0 EFLAGS: 00010202
RAX: 0000000000000008 RBX: ffff888022486000 RCX: ffff88802c4f1dc0
RDX: 0000000000000000 RSI: ffff888022b1e000 RDI: 0000000000000040
RBP: dffffc0000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000683f70 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffff1100b2e282e
FS:  0000555561c85500(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9d95e50e20 CR3: 0000000077378000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	41 5c                	pop    %r12
   2:	41 5e                	pop    %r14
   4:	41 5f                	pop    %r15
   6:	5d                   	pop    %rbp
   7:	c3                   	ret
   8:	e8 49 8c 4d fc       	call   0xfc4d8c56
   d:	43 80 3c 27 00       	cmpb   $0x0,(%r15,%r12,1)
  12:	74 08                	je     0x1c
  14:	4c 89 f7             	mov    %r14,%rdi
  17:	e8 fa bf 92 fc       	call   0xfc92c016
  1c:	4d 8b 36             	mov    (%r14),%r14
  1f:	49 8d 7e 40          	lea    0x40(%r14),%rdi
  23:	48 89 f8             	mov    %rdi,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 0f b6 04 20       	movzbl (%rax,%r12,1),%eax <-- trapping instruction
  2f:	84 c0                	test   %al,%al
  31:	0f 85 cd 00 00 00    	jne    0x104
  37:	41 8b 6e 40          	mov    0x40(%r14),%ebp
  3b:	49 83 c6 38          	add    $0x38,%r14
  3f:	4c                   	rex.WR