syzbot

F2FS-fs (loop5): f2fs_disable_checkpoint() finish, err:0
F2FS-fs (loop5): Mounted with checkpoint version = 48b305e6
general protection fault, probably for non-canonical address 0xdffffc0000000007: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000038-0x000000000000003f]
CPU: 1 PID: 669 Comm: syz.5.72 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:f2fs_test_and_set_bit fs/f2fs/f2fs.h:3004 [inline]
RIP: 0010:update_sit_entry_for_alloc fs/f2fs/segment.c:2399 [inline]
RIP: 0010:update_sit_entry+0x508/0x15c0 fs/f2fs/segment.c:2443
Code: 00 00 fc ff df 80 3c 08 00 74 08 48 89 df e8 df 95 8a ff 48 8b 1b 4c 01 f3 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <0f> b6 04 08 84 c0 0f 85 6d 0f 00 00 44 0f b6 23 44 89 e0 44 08 f8
RSP: 0018:ffffc900013af140 EFLAGS: 00010202
RAX: 0000000000000007 RBX: 000000000000003b RCX: dffffc0000000000
RDX: ffff888118270000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900013af210 R08: ffff888118270000 R09: 0000000000000003
R10: 00000000ffffffff R11: 0000000000000000 R12: 0000000000000000
R13: ffff8881138ec0d8 R14: 000000000000003b R15: 0000000000000020
FS:  00007f1fcbb3c6c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1fcbb1bd58 CR3: 000000011d4b6000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 f2fs_allocate_data_block+0x14ca/0x3b30 fs/f2fs/segment.c:3434
 __allocate_data_block fs/f2fs/data.c:1498 [inline]
 f2fs_map_blocks+0x17c7/0x3d50 fs/f2fs/data.c:1690
 f2fs_expand_inode_data+0x631/0xa60 fs/f2fs/file.c:1860
 f2fs_fallocate+0x3cf/0x730 fs/f2fs/file.c:1961
 vfs_fallocate+0x4c5/0x5a0 fs/open.c:324
 ioctl_preallocate fs/ioctl.c:290 [inline]
 file_ioctl fs/ioctl.c:330 [inline]
 do_vfs_ioctl+0x194b/0x1cd0 fs/ioctl.c:849
 __do_sys_ioctl fs/ioctl.c:868 [inline]
 __se_sys_ioctl+0x9f/0x1b0 fs/ioctl.c:856
 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:856
 x64_sys_call+0x58b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f1fcab9ce59
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:00007f1fcbb3c028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f1fcae15fa0 RCX: 00007f1fcab9ce59
RDX: 00002000000000c0 RSI: 0000000040305828 RDI: 0000000000000004
RBP: 00007f1fcac32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1fcae16038 R14: 00007f1fcae15fa0 R15: 00007ffd4d3a18e8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:f2fs_test_and_set_bit fs/f2fs/f2fs.h:3004 [inline]
RIP: 0010:update_sit_entry_for_alloc fs/f2fs/segment.c:2399 [inline]
RIP: 0010:update_sit_entry+0x508/0x15c0 fs/f2fs/segment.c:2443
Code: 00 00 fc ff df 80 3c 08 00 74 08 48 89 df e8 df 95 8a ff 48 8b 1b 4c 01 f3 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <0f> b6 04 08 84 c0 0f 85 6d 0f 00 00 44 0f b6 23 44 89 e0 44 08 f8
RSP: 0018:ffffc900013af140 EFLAGS: 00010202
RAX: 0000000000000007 RBX: 000000000000003b RCX: dffffc0000000000
RDX: ffff888118270000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900013af210 R08: ffff888118270000 R09: 0000000000000003
R10: 00000000ffffffff R11: 0000000000000000 R12: 0000000000000000
R13: ffff8881138ec0d8 R14: 000000000000003b R15: 0000000000000020
FS:  00007f1fcbb3c6c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fef5d544000 CR3: 000000011d4b6000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	00 00                	add    %al,(%rax)
   2:	fc                   	cld
   3:	ff                   	lcall  (bad)
   4:	df 80 3c 08 00 74    	filds  0x7400083c(%rax)
   a:	08 48 89             	or     %cl,-0x77(%rax)
   d:	df e8                	fucomip %st(0),%st
   f:	df 95 8a ff 48 8b    	fists  -0x74b70076(%rbp)
  15:	1b 4c 01 f3          	sbb    -0xd(%rcx,%rax,1),%ecx
  19:	48 89 d8             	mov    %rbx,%rax
  1c:	48 c1 e8 03          	shr    $0x3,%rax
  20:	48 b9 00 00 00 00 00 	movabs $0xdffffc0000000000,%rcx
  27:	fc ff df
* 2a:	0f b6 04 08          	movzbl (%rax,%rcx,1),%eax <-- trapping instruction
  2e:	84 c0                	test   %al,%al
  30:	0f 85 6d 0f 00 00    	jne    0xfa3
  36:	44 0f b6 23          	movzbl (%rbx),%r12d
  3a:	44 89 e0             	mov    %r12d,%eax
  3d:	44 08 f8             	or     %r15b,%al