syz.0.15[3276]: memfd_create() called without MFD_EXEC or MFD_NOEXEC_SEAL set
loop0: detected capacity change from 0 to 32768
bcachefs (/dev/loop0): error reading default superblock: bad checksum
bcachefs (/dev/loop0): error reading superblock: bad checksum
BUG: kernel NULL pointer dereference, address: 000000000000007c
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 8000000102b8d067 P4D 8000000102b8d067 PUD 10abe0067 PMD 0 
Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 0 PID: 3276 Comm: syz.0.15 Not tainted 6.6.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
RIP: 0010:bch2_sb_field_get+0xb/0x40
Code: cc 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f 1f 00 48 8d 87 f0 02 00 00 <8b> 4f 7c 48 8d 8c cf f0 02 00 00 48 39 c8 73 10 39 70 04 74 0d 8b
RSP: 0018:ffffc900030cfa48 EFLAGS: 00010206
RAX: 00000000000002f0 RBX: 0000000000000001 RCX: ffff888108f1ccc0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900030cfc98 R08: ffff888105b2b9a0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff888108f1ccf8
R13: ffff888108f1ccc0 R14: 0000000000000001 R15: ffffffffffffffed
FS:  00007f0c9ed926c0(0000) GS:ffff888237c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000000007c CR3: 000000010d6ac000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 bch2_sb_get_members fs/bcachefs/super-io.h:48 [inline]
 bch2_fs_open+0x170/0x1470 fs/bcachefs/super.c:1908
 bch2_mount+0x273/0x5b0 fs/bcachefs/fs.c:1829
 legacy_get_tree+0x2d/0x60 fs/fs_context.c:638
 vfs_get_tree+0x24/0xb0 fs/super.c:1750
 do_new_mount+0x153/0x390 fs/namespace.c:3335
 do_mount fs/namespace.c:3675 [inline]
 __do_sys_mount fs/namespace.c:3884 [inline]
 __se_sys_mount+0x14b/0x1c0 fs/namespace.c:3861
 do_syscall_64+0x46/0xc0
 entry_SYSCALL_64_after_hwframe+0x6f/0xd9
RIP: 0033:0x7f0c9df7f69a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f0c9ed91e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f0c9ed91ef0 RCX: 00007f0c9df7f69a
RDX: 0000000020000240 RSI: 0000000020005dc0 RDI: 00007f0c9ed91eb0
RBP: 0000000020000240 R08: 00007f0c9ed91ef0 R09: 0000000001000000
R10: 0000000001000000 R11: 0000000000000246 R12: 0000000020005dc0
R13: 00007f0c9ed91eb0 R14: 0000000000005da6 R15: 0000000020000080
 </TASK>
Modules linked in:
CR2: 000000000000007c
---[ end trace 0000000000000000 ]---
RIP: 0010:bch2_sb_field_get+0xb/0x40
Code: cc 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f 1f 00 48 8d 87 f0 02 00 00 <8b> 4f 7c 48 8d 8c cf f0 02 00 00 48 39 c8 73 10 39 70 04 74 0d 8b
RSP: 0018:ffffc900030cfa48 EFLAGS: 00010206
RAX: 00000000000002f0 RBX: 0000000000000001 RCX: ffff888108f1ccc0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900030cfc98 R08: ffff888105b2b9a0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff888108f1ccf8
R13: ffff888108f1ccc0 R14: 0000000000000001 R15: ffffffffffffffed
FS:  00007f0c9ed926c0(0000) GS:ffff888237c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000000007c CR3: 000000010d6ac000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	cc                   	int3
   1:	66 2e 0f 1f 84 00 00 	cs nopw 0x0(%rax,%rax,1)
   8:	00 00 00
   b:	0f 1f 40 00          	nopl   0x0(%rax)
   f:	90                   	nop
  10:	90                   	nop
  11:	90                   	nop
  12:	90                   	nop
  13:	90                   	nop
  14:	90                   	nop
  15:	90                   	nop
  16:	90                   	nop
  17:	90                   	nop
  18:	90                   	nop
  19:	90                   	nop
  1a:	90                   	nop
  1b:	90                   	nop
  1c:	90                   	nop
  1d:	90                   	nop
  1e:	90                   	nop
  1f:	66 0f 1f 00          	nopw   (%rax)
  23:	48 8d 87 f0 02 00 00 	lea    0x2f0(%rdi),%rax
* 2a:	8b 4f 7c             	mov    0x7c(%rdi),%ecx <-- trapping instruction
  2d:	48 8d 8c cf f0 02 00 	lea    0x2f0(%rdi,%rcx,8),%rcx
  34:	00
  35:	48 39 c8             	cmp    %rcx,%rax
  38:	73 10                	jae    0x4a
  3a:	39 70 04             	cmp    %esi,0x4(%rax)
  3d:	74 0d                	je     0x4c
  3f:	8b                   	.byte 0x8b