syzbot

general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 PID: 1058 Comm: syz.6.144 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:f2fs_test_and_set_bit fs/f2fs/f2fs.h:2952 [inline]
RIP: 0010:update_sit_entry_for_alloc fs/f2fs/segment.c:2396 [inline]
RIP: 0010:update_sit_entry+0x4f9/0x15a0 fs/f2fs/segment.c:2440
Code: 00 00 fc ff df 80 3c 08 00 74 08 48 89 df e8 de e2 8c 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 55 0f 00 00 44 0f b6 23 44 89 e0 44 08 f8
RSP: 0018:ffffc90002fcf1e0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: dffffc0000000000
RDX: ffff88811a403cc0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90002fcf2b0 R08: ffff88811a403cc0 R09: 0000000000000003
R10: 00000000ffffffff R11: 0000000000000000 R12: 0000000000000000
R13: ffff8881098600c8 R14: 0000000000000000 R15: 0000000000000080
FS:  00007fc3158226c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc315821f98 CR3: 00000001175d8000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 f2fs_allocate_data_block+0x148c/0x3af0 fs/f2fs/segment.c:3430
 __allocate_data_block fs/f2fs/data.c:1488 [inline]
 f2fs_map_blocks+0x11a8/0x3a60 fs/f2fs/data.c:1671
 f2fs_expand_inode_data+0x639/0xa70 fs/f2fs/file.c:1847
 f2fs_fallocate+0x3cc/0x720 fs/f2fs/file.c:1948
 vfs_fallocate+0x4c5/0x5a0 fs/open.c:324
 ioctl_preallocate fs/ioctl.c:290 [inline]
 file_ioctl fs/ioctl.c:-1 [inline]
 do_vfs_ioctl+0x1a1d/0x1c80 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:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc31498f749
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:00007fc315822038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fc314be6090 RCX: 00007fc31498f749
RDX: 00002000000000c0 RSI: 0000000040305828 RDI: 0000000000000004
RBP: 00007fc314a13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc314be6128 R14: 00007fc314be6090 R15: 00007fffb9d37238
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:f2fs_test_and_set_bit fs/f2fs/f2fs.h:2952 [inline]
RIP: 0010:update_sit_entry_for_alloc fs/f2fs/segment.c:2396 [inline]
RIP: 0010:update_sit_entry+0x4f9/0x15a0 fs/f2fs/segment.c:2440
Code: 00 00 fc ff df 80 3c 08 00 74 08 48 89 df e8 de e2 8c 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 55 0f 00 00 44 0f b6 23 44 89 e0 44 08 f8
RSP: 0018:ffffc90002fcf1e0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: dffffc0000000000
RDX: ffff88811a403cc0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90002fcf2b0 R08: ffff88811a403cc0 R09: 0000000000000003
R10: 00000000ffffffff R11: 0000000000000000 R12: 0000000000000000
R13: ffff8881098600c8 R14: 0000000000000000 R15: 0000000000000080
FS:  00007fc3158226c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f468b3f4000 CR3: 00000001175d8000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 4 bytes skipped:
   0:	df 80 3c 08 00 74    	filds  0x7400083c(%rax)
   6:	08 48 89             	or     %cl,-0x77(%rax)
   9:	df e8                	fucomip %st(0),%st
   b:	de e2                	fsubp  %st,%st(2)
   d:	8c ff                	mov    %?,%edi
   f:	48 8b 1b             	mov    (%rbx),%rbx
  12:	4c 01 f3             	add    %r14,%rbx
  15:	48 89 d8             	mov    %rbx,%rax
  18:	48 c1 e8 03          	shr    $0x3,%rax
  1c:	48 b9 00 00 00 00 00 	movabs $0xdffffc0000000000,%rcx
  23:	fc ff df
* 26:	0f b6 04 08          	movzbl (%rax,%rcx,1),%eax <-- trapping instruction
  2a:	84 c0                	test   %al,%al
  2c:	0f 85 55 0f 00 00    	jne    0xf87
  32:	44 0f b6 23          	movzbl (%rbx),%r12d
  36:	44 89 e0             	mov    %r12d,%eax
  39:	44 08 f8             	or     %r15b,%al