general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 PID: 5892 Comm: syz-executor.4 Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
RIP: 0010:shmem_get_next_id+0x94/0x4b0 mm/shmem_quota.c:119
Code: 48 8d 7b 40 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 11 04 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 5b 40 48 89 da 48 c1 ea 03 <80> 3c 02 00 0f 85 e5 03 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89
RSP: 0018:ffffc9000423fad8 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc9000423fbac
RDX: 0000000000000000 RSI: ffffffff81cd6d9d RDI: ffff88801e3ae2d8
RBP: ffff88801e3ae000 R08: 0000000000000005 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000001 R12: ffffc9000423fc38
R13: ffffc9000423fba8 R14: ffffc9000423fba8 R15: ffff88801e3ae040
FS:  00007f9ca0bf86c0(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b30d26000 CR3: 000000006bce0000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 dquot_get_next_dqblk+0x74/0x180 fs/quota/dquot.c:2705
 quota_getnextquota+0x26d/0x470 fs/quota/quota.c:250
 do_quotactl+0x3d1/0x13e0 fs/quota/quota.c:800
 __do_sys_quotactl_fd fs/quota/quota.c:1002 [inline]
 __se_sys_quotactl_fd fs/quota/quota.c:973 [inline]
 __x64_sys_quotactl_fd+0x2e6/0x510 fs/quota/quota.c:973
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x6d/0x75
RIP: 0033:0x7f9c9fe7dda9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f9ca0bf80c8 EFLAGS: 00000246 ORIG_RAX: 00000000000001bb
RAX: ffffffffffffffda RBX: 00007f9c9ffabf80 RCX: 00007f9c9fe7dda9
RDX: 0000000000000000 RSI: ffffffff80000901 RDI: 0000000000000003
RBP: 00007f9c9feca47a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f9c9ffabf80 R15: 00007ffd1e292e08
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:shmem_get_next_id+0x94/0x4b0 mm/shmem_quota.c:119
Code: 48 8d 7b 40 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 11 04 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 5b 40 48 89 da 48 c1 ea 03 <80> 3c 02 00 0f 85 e5 03 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89
RSP: 0018:ffffc9000423fad8 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc9000423fbac
RDX: 0000000000000000 RSI: ffffffff81cd6d9d RDI: ffff88801e3ae2d8
RBP: ffff88801e3ae000 R08: 0000000000000005 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000001 R12: ffffc9000423fc38
R13: ffffc9000423fba8 R14: ffffc9000423fba8 R15: ffff88801e3ae040
FS:  00007f9ca0bf86c0(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f01980ee440 CR3: 000000006bce0000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	48 8d 7b 40          	lea    0x40(%rbx),%rdi
   4:	48 89 fa             	mov    %rdi,%rdx
   7:	48 c1 ea 03          	shr    $0x3,%rdx
   b:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
   f:	0f 85 11 04 00 00    	jne    0x426
  15:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  1c:	fc ff df
  1f:	48 8b 5b 40          	mov    0x40(%rbx),%rbx
  23:	48 89 da             	mov    %rbx,%rdx
  26:	48 c1 ea 03          	shr    $0x3,%rdx
* 2a:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1) <-- trapping instruction
  2e:	0f 85 e5 03 00 00    	jne    0x419
  34:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  3b:	fc ff df
  3e:	4c                   	rex.WR
  3f:	89                   	.byte 0x89