Oops: general protection fault, probably for non-canonical address 0xdffffc000000000c: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000060-0x0000000000000067]
CPU: 0 UID: 0 PID: 70 Comm: kworker/u4:4 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Workqueue: writeback wb_workfn (flush-7:0)
RIP: 0010:f2fs_dev_is_alloc_blocked fs/f2fs/segment.h:956 [inline]
RIP: 0010:get_new_segment fs/f2fs/segment.c:2964 [inline]
RIP: 0010:new_curseg+0x1134/0x3580 fs/f2fs/segment.c:3110
Code: e8 81 d9 ce fd 48 8b 7c 24 30 48 8b 07 49 6b cf 70 4c 8d 34 08 49 83 c6 61 4c 89 f0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <0f> b6 04 08 84 c0 0f 85 73 11 00 00 41 80 3e 00 0f 84 e6 00 00 00
RSP: 0018:ffffc90000ae6628 EFLAGS: 00010206
RAX: 000000000000000c RBX: 0000000000008000 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000008000 RDI: ffff8880128f1a88
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200015ccb4 R12: ffff8880123a0000
R13: 0000000000000004 R14: 0000000000000061 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff88808c2d1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fafed1f6000 CR3: 00000000405ce000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 f2fs_allocate_data_block+0x229c/0x43c0 fs/f2fs/segment.c:3979
 do_write_page+0x13f/0x880 fs/f2fs/segment.c:4099
 f2fs_outplace_write_data+0x11a/0x220 fs/f2fs/segment.c:4175
 f2fs_write_compressed_pages fs/f2fs/compress.c:1403 [inline]
 f2fs_write_multi_pages+0x43bb/0x6370 fs/f2fs/compress.c:1602
 f2fs_write_cache_pages fs/f2fs/data.c:3351 [inline]
 __f2fs_write_data_pages fs/f2fs/data.c:3603 [inline]
 f2fs_write_data_pages+0x19bb/0x36f0 fs/f2fs/data.c:3641
 do_writepages+0x338/0x560 mm/page-writeback.c:2560
 __writeback_single_inode+0x136/0x1220 fs/fs-writeback.c:1788
 writeback_sb_inodes+0x9de/0x1b00 fs/fs-writeback.c:2099
 __writeback_inodes_wb+0x114/0x240 fs/fs-writeback.c:2175
 wb_writeback+0x42f/0xad0 fs/fs-writeback.c:2286
 wb_check_start_all fs/fs-writeback.c:2412 [inline]
 wb_do_writeback fs/fs-writeback.c:2459 [inline]
 wb_workfn+0x980/0x10f0 fs/fs-writeback.c:2497
 process_one_work kernel/workqueue.c:3387 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3470
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3551
 kthread+0x38b/0x480 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:f2fs_dev_is_alloc_blocked fs/f2fs/segment.h:956 [inline]
RIP: 0010:get_new_segment fs/f2fs/segment.c:2964 [inline]
RIP: 0010:new_curseg+0x1134/0x3580 fs/f2fs/segment.c:3110
Code: e8 81 d9 ce fd 48 8b 7c 24 30 48 8b 07 49 6b cf 70 4c 8d 34 08 49 83 c6 61 4c 89 f0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <0f> b6 04 08 84 c0 0f 85 73 11 00 00 41 80 3e 00 0f 84 e6 00 00 00
RSP: 0018:ffffc90000ae6628 EFLAGS: 00010206
RAX: 000000000000000c RBX: 0000000000008000 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000008000 RDI: ffff8880128f1a88
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200015ccb4 R12: ffff8880123a0000
R13: 0000000000000004 R14: 0000000000000061 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff88808c2d1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fafed1f6000 CR3: 00000000405ce000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess):
   0:	e8 81 d9 ce fd       	call   0xfdced986
   5:	48 8b 7c 24 30       	mov    0x30(%rsp),%rdi
   a:	48 8b 07             	mov    (%rdi),%rax
   d:	49 6b cf 70          	imul   $0x70,%r15,%rcx
  11:	4c 8d 34 08          	lea    (%rax,%rcx,1),%r14
  15:	49 83 c6 61          	add    $0x61,%r14
  19:	4c 89 f0             	mov    %r14,%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 73 11 00 00    	jne    0x11a9
  36:	41 80 3e 00          	cmpb   $0x0,(%r14)
  3a:	0f 84 e6 00 00 00    	je     0x126