syzbot

F2FS-fs (loop0): Found nat_bits in checkpoint
F2FS-fs (loop0): Start checkpoint disabled!
F2FS-fs (loop0): Mounted with checkpoint version = 48b305e6
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 PID: 4426 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:f2fs_test_and_set_bit fs/f2fs/f2fs.h:2932 [inline]
RIP: 0010:update_sit_entry+0x626/0xf30 fs/f2fs/segment.c:2227
Code: 01 00 00 48 8d 5d 20 48 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 27 aa 2a fe 48 8b 1b 4c 01 e3 48 89 d8 48 c1 e8 03 <42> 0f b6 04 38 84 c0 0f 85 ae 07 00 00 0f b6 2b 89 e8 44 8b 74 24
RSP: 0018:ffffc900035372f0 EFLAGS: 00010247
RAX: 0000000000000000 RBX: 0000000000000006 RCX: 0000000000000000
RDX: ffff88807c990000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff8880798f0240 R08: ffff88807c990000 R09: 0000000000000003
R10: 00000000ffffffff R11: 0000000000000000 R12: 0000000000000006
R13: ffff888019288000 R14: ffff88801928c906 R15: dffffc0000000000
FS:  00007fb2d1b476c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb2d03fdf98 CR3: 0000000078a79000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 f2fs_allocate_data_block+0x13f8/0x35e0 fs/f2fs/segment.c:3275
 __allocate_data_block+0x519/0x9f0 fs/f2fs/data.c:1424
 f2fs_map_blocks+0x1007/0x33d0 fs/f2fs/data.c:1608
 expand_inode_data+0x4a1/0x860 fs/f2fs/file.c:1803
 f2fs_fallocate+0x4c3/0x950 fs/f2fs/file.c:1906
 vfs_fallocate+0x584/0x6f0 fs/open.c:323
 ioctl_preallocate fs/ioctl.c:290 [inline]
 file_ioctl fs/ioctl.c:-1 [inline]
 do_vfs_ioctl+0x1a9d/0x1d10 fs/ioctl.c:849
 __do_sys_ioctl fs/ioctl.c:868 [inline]
 __se_sys_ioctl+0x83/0x170 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fb2d0d8f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb2d1b47038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fb2d0fe5fa0 RCX: 00007fb2d0d8f749
RDX: 00002000000000c0 RSI: 0000000040305828 RDI: 0000000000000004
RBP: 00007fb2d0e13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb2d0fe6038 R14: 00007fb2d0fe5fa0 R15: 00007ffcfb9165c8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:f2fs_test_and_set_bit fs/f2fs/f2fs.h:2932 [inline]
RIP: 0010:update_sit_entry+0x626/0xf30 fs/f2fs/segment.c:2227
Code: 01 00 00 48 8d 5d 20 48 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 27 aa 2a fe 48 8b 1b 4c 01 e3 48 89 d8 48 c1 e8 03 <42> 0f b6 04 38 84 c0 0f 85 ae 07 00 00 0f b6 2b 89 e8 44 8b 74 24
RSP: 0018:ffffc900035372f0 EFLAGS: 00010247
RAX: 0000000000000000 RBX: 0000000000000006 RCX: 0000000000000000
RDX: ffff88807c990000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff8880798f0240 R08: ffff88807c990000 R09: 0000000000000003
R10: 00000000ffffffff R11: 0000000000000000 R12: 0000000000000006
R13: ffff888019288000 R14: ffff88801928c906 R15: dffffc0000000000
FS:  00007fb2d1b476c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000557e98b36980 CR3: 0000000078a79000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	01 00                	add    %eax,(%rax)
   2:	00 48 8d             	add    %cl,-0x73(%rax)
   5:	5d                   	pop    %rbp
   6:	20 48 89             	and    %cl,-0x77(%rax)
   9:	d8 48 c1             	fmuls  -0x3f(%rax)
   c:	e8 03 42 80 3c       	call   0x3c804214
  11:	38 00                	cmp    %al,(%rax)
  13:	74 08                	je     0x1d
  15:	48 89 df             	mov    %rbx,%rdi
  18:	e8 27 aa 2a fe       	call   0xfe2aaa44
  1d:	48 8b 1b             	mov    (%rbx),%rbx
  20:	4c 01 e3             	add    %r12,%rbx
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 0f b6 04 38       	movzbl (%rax,%r15,1),%eax <-- trapping instruction
  2f:	84 c0                	test   %al,%al
  31:	0f 85 ae 07 00 00    	jne    0x7e5
  37:	0f b6 2b             	movzbl (%rbx),%ebp
  3a:	89 e8                	mov    %ebp,%eax
  3c:	44                   	rex.R
  3d:	8b                   	.byte 0x8b
  3e:	74 24                	je     0x64