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 50 4b 8d 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 24 4b 8d ff 4c 89 ef
RSP: 0018:ffffc9000d4de4d8 EFLAGS: 00010206
RAX: 0000000000000005 RBX: 0000000000000200 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000040 RDI: ffff8880514e5848
RBP: ffff888032164e70 R08: ffffea00012e11b7 R09: 1ffffd400025c236
R10: dffffc0000000000 R11: fffff9400025c237 R12: 0000000000000028
R13: ffff8880514e5828 R14: 0000000000000000 R15: 000000000000002a
FS:  00007fa3d59476c0(0000) GS:ffff88808d732000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001940 CR3: 0000000042e4c000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 __block_write_begin_int+0x6b5/0x1900 fs/buffer.c:2145
 block_write_begin+0x8a/0x120 fs/buffer.c:2256
 bfs_write_begin+0x35/0xd0 fs/bfs/file.c:180
 generic_perform_write+0x2c5/0x900 mm/filemap.c:4242
 generic_file_write_iter+0x117/0x550 mm/filemap.c:4385
 __kernel_write_iter+0x428/0x910 fs/read_write.c:619
 __kernel_write+0xef/0x150 fs/read_write.c:639
 __dump_emit+0x206/0x310 fs/coredump.c:1220
 writenote+0x1be/0x2e0 fs/binfmt_elf.c:1434
 write_note_info fs/binfmt_elf.c:1934 [inline]
 elf_core_dump+0x2e19/0x3960 fs/binfmt_elf.c:2098
 coredump_write+0x116c/0x1900 fs/coredump.c:1049
 vfs_coredump+0x1db5/0x2a60 fs/coredump.c:1170
 get_signal+0x1108/0x1340 kernel/signal.c:3019
 arch_do_signal_or_restart+0xa0/0x790 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:40 [inline]
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 irqentry_exit_to_user_mode+0x7e/0x110 kernel/entry/common.c:73
 exc_page_fault+0xab/0x100 arch/x86/mm/fault.c:1535
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 002b:0000200000000308 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007fa3d4de6180 RCX: 00007fa3d4b8efc9
RDX: 0000200000000080 RSI: 0000200000000300 RDI: 0000000084002000
RBP: 00007fa3d4c11f91 R08: 0000200000000340 R09: 0000200000000340
R10: 0000200000000300 R11: 0000000000000206 R12: 0000000000000000
R13: 00007fa3d4de6218 R14: 00007fa3d4de6180 R15: 00007fffefeea708
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
----------------
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 50 4b 8d ff       	call   0xff8d4b61
  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 24 4b 8d ff       	call   0xff8d4b61
  3d:	4c 89 ef             	mov    %r13,%rdi