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: 1 UID: 0 PID: 13507 Comm: kworker/u8:6 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: loop2 loop_workfn
RIP: 0010:file_inode include/linux/fs.h:1353 [inline]
RIP: 0010:kiocb_start_write include/linux/fs.h:2765 [inline]
RIP: 0010:lo_rw_aio+0xa9f/0xf30 drivers/block/loop.c:397
Code: 89 33 31 ff 8b 5c 24 34 89 de e8 8c 4b 3d fc 85 db 0f 84 cb 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 20 00 74 08 48 89 df e8 32 86 a4 fc 4c 89 7c 24 20 48 8b
RSP: 0018:ffffc90006017640 EFLAGS: 00010206
RAX: 0000000000000014 RBX: 00000000000000a0 RCX: ffff888036321f00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900060177b0 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed1004ca8c85 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: ffff888026546430
FS:  0000000000000000(0000) GS:ffff88812647d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555573d8a68 CR3: 0000000032586000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 do_req_filebacked drivers/block/loop.c:429 [inline]
 loop_handle_cmd drivers/block/loop.c:1921 [inline]
 loop_process_work+0x638/0x11d0 drivers/block/loop.c:1956
 process_one_work kernel/workqueue.c:3314 [inline]
 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3397
 worker_thread+0xa47/0xfb0 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:2765 [inline]
RIP: 0010:lo_rw_aio+0xa9f/0xf30 drivers/block/loop.c:397
Code: 89 33 31 ff 8b 5c 24 34 89 de e8 8c 4b 3d fc 85 db 0f 84 cb 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 20 00 74 08 48 89 df e8 32 86 a4 fc 4c 89 7c 24 20 48 8b
RSP: 0018:ffffc90006017640 EFLAGS: 00010206
RAX: 0000000000000014 RBX: 00000000000000a0 RCX: ffff888036321f00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900060177b0 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed1004ca8c85 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: ffff888026546430
FS:  0000000000000000(0000) GS:ffff88812647d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555573d8a68 CR3: 00000000354ba000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	89 33                	mov    %esi,(%rbx)
   2:	31 ff                	xor    %edi,%edi
   4:	8b 5c 24 34          	mov    0x34(%rsp),%ebx
   8:	89 de                	mov    %ebx,%esi
   a:	e8 8c 4b 3d fc       	call   0xfc3d4b9b
   f:	85 db                	test   %ebx,%ebx
  11:	0f 84 cb 00 00 00    	je     0xe2
  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 20 00       	cmpb   $0x0,(%rax,%r12,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	48 89 df             	mov    %rbx,%rdi
  34:	e8 32 86 a4 fc       	call   0xfca4866b
  39:	4c 89 7c 24 20       	mov    %r15,0x20(%rsp)
  3e:	48                   	rex.W
  3f:	8b                   	.byte 0x8b