Oops: general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f]
CPU: 0 UID: 0 PID: 5336 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:bfs_move_block fs/bfs/file.c:43 [inline]
RIP: 0010:bfs_move_blocks fs/bfs/file.c:57 [inline]
RIP: 0010:bfs_get_block+0x589/0xae0 fs/bfs/file.c:126
Code: f8 48 c1 e8 03 42 80 3c 20 00 74 05 e8 20 71 8b ff 49 8b 5d 20 4d 8d 66 28 4c 89 e0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 48 8b 6c 24 18 74 08 4c 89 e7 e8 f4 70 8b ff 4c 89 ef
RSP: 0018:ffffc9000de77638 EFLAGS: 00010206
RAX: 0000000000000005 RBX: 0000000000000200 RCX: dffffc0000000000
RDX: ffffc900211e3000 RSI: 0000000000000287 RDI: ffff888012040ea0
RBP: ffff8880008d4e70 R08: ffffea00007f19b7 R09: 1ffffd40000fe336
R10: dffffc0000000000 R11: fffff940000fe337 R12: 0000000000000028
R13: ffff888012040e80 R14: 0000000000000000 R15: 000000000000000a
FS:  00007f60b42f06c0(0000) GS:ffff88808d239000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f60b42effc8 CR3: 000000001174e000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 __block_write_begin_int+0x6b5/0x1900 fs/buffer.c:2145
 block_write_begin+0x8d/0x120 fs/buffer.c:2256
 bfs_write_begin+0x35/0xd0 fs/bfs/file.c:180
 generic_perform_write+0x2c5/0x900 mm/filemap.c:4314
 generic_file_write_iter+0x117/0x550 mm/filemap.c:4457
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x5c9/0xb30 fs/read_write.c:686
 ksys_pwrite64 fs/read_write.c:793 [inline]
 __do_sys_pwrite64 fs/read_write.c:801 [inline]
 __se_sys_pwrite64 fs/read_write.c:798 [inline]
 __x64_sys_pwrite64+0x193/0x220 fs/read_write.c:798
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f60b338f7c9
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:00007f60b42f0038 EFLAGS: 00000246 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 00007f60b35e6090 RCX: 00007f60b338f7c9
RDX: 000000000000fdef RSI: 0000200000000140 RDI: 0000000000000007
RBP: 00007f60b3413f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000e7c R11: 0000000000000246 R12: 0000000000000000
R13: 00007f60b35e6128 R14: 00007f60b35e6090 R15: 00007fffe3a8c548
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:bfs_move_block fs/bfs/file.c:43 [inline]
RIP: 0010:bfs_move_blocks fs/bfs/file.c:57 [inline]
RIP: 0010:bfs_get_block+0x589/0xae0 fs/bfs/file.c:126
Code: f8 48 c1 e8 03 42 80 3c 20 00 74 05 e8 20 71 8b ff 49 8b 5d 20 4d 8d 66 28 4c 89 e0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 48 8b 6c 24 18 74 08 4c 89 e7 e8 f4 70 8b ff 4c 89 ef
RSP: 0018:ffffc9000de77638 EFLAGS: 00010206
RAX: 0000000000000005 RBX: 0000000000000200 RCX: dffffc0000000000
RDX: ffffc900211e3000 RSI: 0000000000000287 RDI: ffff888012040ea0
RBP: ffff8880008d4e70 R08: ffffea00007f19b7 R09: 1ffffd40000fe336
R10: dffffc0000000000 R11: fffff940000fe337 R12: 0000000000000028
R13: ffff888012040e80 R14: 0000000000000000 R15: 000000000000000a
FS:  00007f60b42f06c0(0000) GS:ffff88808d239000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f36b8786d50 CR3: 000000001174e000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess):
   0:	f8                   	clc
   1:	48 c1 e8 03          	shr    $0x3,%rax
   5:	42 80 3c 20 00       	cmpb   $0x0,(%rax,%r12,1)
   a:	74 05                	je     0x11
   c:	e8 20 71 8b ff       	call   0xff8b7131
  11:	49 8b 5d 20          	mov    0x20(%r13),%rbx
  15:	4d 8d 66 28          	lea    0x28(%r14),%r12
  19:	4c 89 e0             	mov    %r12,%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:	80 3c 08 00          	cmpb   $0x0,(%rax,%rcx,1) <-- trapping instruction
  2e:	48 8b 6c 24 18       	mov    0x18(%rsp),%rbp
  33:	74 08                	je     0x3d
  35:	4c 89 e7             	mov    %r12,%rdi
  38:	e8 f4 70 8b ff       	call   0xff8b7131
  3d:	4c 89 ef             	mov    %r13,%rdi