BUG: kernel NULL pointer dereference, address: 000000000000000c
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 800000010fb05067 P4D 800000010fb05067 PUD 0 
Oops: Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 0 UID: 0 PID: 11 Comm: kworker/u8:0 Not tainted 6.13.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: loop5 loop_rootcg_workfn

RIP: 0010:atime_needs_update+0x9/0x120 fs/inode.c:2144
Code: c6 e8 3b 03 02 00 31 c0 5b c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f 1f 00 41 57 41 56 53 <f6> 46 0c 02 75 4f 48 89 f3 4c 8b 3f 4d 8b 77 18 48 8b 46 28 48 8b
RSP: 0018:ffffc90000063b68 EFLAGS: 00010283
RAX: ffff88817b07daf8 RBX: 0000000000000000 RCX: 0000000000000040
RDX: 00000000ffffff01 RSI: 0000000000000000 RDI: ffff888103b1b580
RBP: 0000000000001000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffffc90000063d00 R14: ffff888100efe020 R15: 0000000000001000
FS:  0000000000000000(0000) GS:ffff888237c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000000000c CR3: 0000000104f42000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 touch_atime+0x1f/0x1c0 fs/inode.c:2180
 file_accessed include/linux/fs.h:2539 [inline]
 shmem_file_read_iter+0x22f/0x2b0 mm/shmem.c:3273
 do_iter_readv_writev+0x172/0x1c0
 vfs_iter_read+0xa9/0x190 fs/read_write.c:909
 lo_read_simple drivers/block/loop.c:283 [inline]
 do_req_filebacked drivers/block/loop.c:516 [inline]
 loop_handle_cmd drivers/block/loop.c:1909 [inline]
 loop_process_work+0x46c/0x9e0 drivers/block/loop.c:1944
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0x2e6/0x6b0 kernel/workqueue.c:3310
 worker_thread+0x212/0x2d0 kernel/workqueue.c:3391
 kthread+0xf5/0x110 kernel/kthread.c:389
 ret_from_fork+0x32/0x40 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Modules linked in:
CR2: 000000000000000c
---[ end trace 0000000000000000 ]---
RIP: 0010:atime_needs_update+0x9/0x120 fs/inode.c:2144
Code: c6 e8 3b 03 02 00 31 c0 5b c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f 1f 00 41 57 41 56 53 <f6> 46 0c 02 75 4f 48 89 f3 4c 8b 3f 4d 8b 77 18 48 8b 46 28 48 8b
RSP: 0018:ffffc90000063b68 EFLAGS: 00010283
RAX: ffff88817b07daf8 RBX: 0000000000000000 RCX: 0000000000000040
RDX: 00000000ffffff01 RSI: 0000000000000000 RDI: ffff888103b1b580
RBP: 0000000000001000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffffc90000063d00 R14: ffff888100efe020 R15: 0000000000001000
FS:  0000000000000000(0000) GS:ffff888237c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000000000c CR3: 0000000104f42000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	e8 3b 03 02 00       	call   0x20340
   5:	31 c0                	xor    %eax,%eax
   7:	5b                   	pop    %rbx
   8:	c3                   	ret
   9:	cc                   	int3
   a:	cc                   	int3
   b:	cc                   	int3
   c:	cc                   	int3
   d:	0f 1f 00             	nopl   (%rax)
  10:	90                   	nop
  11:	90                   	nop
  12:	90                   	nop
  13:	90                   	nop
  14:	90                   	nop
  15:	90                   	nop
  16:	90                   	nop
  17:	90                   	nop
  18:	90                   	nop
  19:	90                   	nop
  1a:	90                   	nop
  1b:	90                   	nop
  1c:	90                   	nop
  1d:	90                   	nop
  1e:	90                   	nop
  1f:	90                   	nop
  20:	66 0f 1f 00          	nopw   (%rax)
  24:	41 57                	push   %r15
  26:	41 56                	push   %r14
  28:	53                   	push   %rbx
* 29:	f6 46 0c 02          	testb  $0x2,0xc(%rsi) <-- trapping instruction
  2d:	75 4f                	jne    0x7e
  2f:	48 89 f3             	mov    %rsi,%rbx
  32:	4c 8b 3f             	mov    (%rdi),%r15
  35:	4d 8b 77 18          	mov    0x18(%r15),%r14
  39:	48 8b 46 28          	mov    0x28(%rsi),%rax
  3d:	48                   	rex.W
  3e:	8b                   	.byte 0x8b