syzbot

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000014: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x00000000000000a0-0x00000000000000a7]
CPU: 0 UID: 0 PID: 1177 Comm: kworker/u8:8 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: loop2 loop_workfn
RIP: 0010:file_inode include/linux/fs.h:1353 [inline]
RIP: 0010:kiocb_start_write include/linux/fs.h:2756 [inline]
RIP: 0010:lo_rw_aio+0xaa9/0xf00 drivers/block/loop.c:401
Code: 89 33 31 ff 8b 5c 24 44 89 de e8 e2 48 3d fc 85 db 0f 84 ca 00 00 00 48 8b 44 24 58 48 8d 98 a0 00 00 00 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 74 08 48 89 df e8 f8 4f a4 fc 4c 89 7c 24 10 48 8b
RSP: 0018:ffffc90006367620 EFLAGS: 00010206
RAX: 0000000000000014 RBX: 00000000000000a0 RCX: ffff888028f18000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90006367790 R08: 0000000000000000 R09: 0000000000000000
R10: ffffc900063676e3 R11: fffff52000c6cede R12: ffff8880262f8e10
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8880262f8e30
FS:  0000000000000000(0000) GS:ffff888126174000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555759bda68 CR3: 000000003f3fe000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 do_req_filebacked drivers/block/loop.c:433 [inline]
 loop_handle_cmd drivers/block/loop.c:1925 [inline]
 loop_process_work+0x637/0x11b0 drivers/block/loop.c:1960
 process_one_work kernel/workqueue.c:3314 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478
 kthread+0x388/0x470 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:file_inode include/linux/fs.h:1353 [inline]
RIP: 0010:kiocb_start_write include/linux/fs.h:2756 [inline]
RIP: 0010:lo_rw_aio+0xaa9/0xf00 drivers/block/loop.c:401
Code: 89 33 31 ff 8b 5c 24 44 89 de e8 e2 48 3d fc 85 db 0f 84 ca 00 00 00 48 8b 44 24 58 48 8d 98 a0 00 00 00 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 74 08 48 89 df e8 f8 4f a4 fc 4c 89 7c 24 10 48 8b
RSP: 0018:ffffc90006367620 EFLAGS: 00010206
RAX: 0000000000000014 RBX: 00000000000000a0 RCX: ffff888028f18000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90006367790 R08: 0000000000000000 R09: 0000000000000000
R10: ffffc900063676e3 R11: fffff52000c6cede R12: ffff8880262f8e10
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8880262f8e30
FS:  0000000000000000(0000) GS:ffff888126174000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555759bda68 CR3: 000000003f3fe000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	89 33                	mov    %esi,(%rbx)
   2:	31 ff                	xor    %edi,%edi
   4:	8b 5c 24 44          	mov    0x44(%rsp),%ebx
   8:	89 de                	mov    %ebx,%esi
   a:	e8 e2 48 3d fc       	call   0xfc3d48f1
   f:	85 db                	test   %ebx,%ebx
  11:	0f 84 ca 00 00 00    	je     0xe1
  17:	48 8b 44 24 58       	mov    0x58(%rsp),%rax
  1c:	48 8d 98 a0 00 00 00 	lea    0xa0(%rax),%rbx
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	48 89 df             	mov    %rbx,%rdi
  34:	e8 f8 4f a4 fc       	call   0xfca45031
  39:	4c 89 7c 24 10       	mov    %r15,0x10(%rsp)
  3e:	48                   	rex.W
  3f:	8b                   	.byte 0x8b