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: 7871 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+0x92/0x5c0 mm/shmem_quota.c:119 Code: 04 db 49 8d 9c c6 90 02 00 00 48 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 88 db 1a 00 48 8b 1b 48 89 d8 48 c1 e8 03 <42> 80 3c 38 00 74 08 48 89 df e8 6f db 1a 00 4c 8b 23 48 8d 5d 07 RSP: 0018:ffffc900036bfbe0 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000040000 RDX: ffffc9000b2e8000 RSI: 0000000000000787 RDI: 0000000000000788 RBP: ffffc900036bfd00 R08: ffffffff81da1997 R09: ffffffff822b2bea R10: 0000000000000003 R11: ffffffff81da1940 R12: 1ffff920006d7fa0 R13: ffff88802bf0e000 R14: ffff88802bf0e000 R15: dffffc0000000000 FS: 00007fa5c02d06c0(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b30423000 CR3: 000000002d256000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 00000000000000c5 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: dquot_get_next_dqblk+0x73/0x3a0 fs/quota/dquot.c:2705 quota_getnextquota+0x2c5/0x6c0 fs/quota/quota.c:250 __do_sys_quotactl_fd fs/quota/quota.c:1002 [inline] __se_sys_quotactl_fd+0x2a1/0x440 fs/quota/quota.c:973 do_syscall_64+0xfb/0x240 entry_SYSCALL_64_after_hwframe+0x6d/0x75 RIP: 0033:0x7fa5bf47dda9 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:00007fa5c02d00c8 EFLAGS: 00000246 ORIG_RAX: 00000000000001bb RAX: ffffffffffffffda RBX: 00007fa5bf5abf80 RCX: 00007fa5bf47dda9 RDX: 0000000000000000 RSI: ffffffff80000901 RDI: 0000000000000003 RBP: 00007fa5bf4ca47a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007fa5bf5abf80 R15: 00007ffe9a5c7298 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:shmem_get_next_id+0x92/0x5c0 mm/shmem_quota.c:119 Code: 04 db 49 8d 9c c6 90 02 00 00 48 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 88 db 1a 00 48 8b 1b 48 89 d8 48 c1 e8 03 <42> 80 3c 38 00 74 08 48 89 df e8 6f db 1a 00 4c 8b 23 48 8d 5d 07 RSP: 0018:ffffc900036bfbe0 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000040000 RDX: ffffc9000b2e8000 RSI: 0000000000000787 RDI: 0000000000000788 RBP: ffffc900036bfd00 R08: ffffffff81da1997 R09: ffffffff822b2bea R10: 0000000000000003 R11: ffffffff81da1940 R12: 1ffff920006d7fa0 R13: ffff88802bf0e000 R14: ffff88802bf0e000 R15: dffffc0000000000 FS: 00007fa5c02d06c0(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000440 CR3: 000000002d256000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 00000000000000c5 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 04 db add $0xdb,%al 2: 49 8d 9c c6 90 02 00 lea 0x290(%r14,%rax,8),%rbx 9: 00 a: 48 89 d8 mov %rbx,%rax d: 48 c1 e8 03 shr $0x3,%rax 11: 42 80 3c 38 00 cmpb $0x0,(%rax,%r15,1) 16: 74 08 je 0x20 18: 48 89 df mov %rbx,%rdi 1b: e8 88 db 1a 00 call 0x1adba8 20: 48 8b 1b mov (%rbx),%rbx 23: 48 89 d8 mov %rbx,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 42 80 3c 38 00 cmpb $0x0,(%rax,%r15,1) <-- trapping instruction 2f: 74 08 je 0x39 31: 48 89 df mov %rbx,%rdi 34: e8 6f db 1a 00 call 0x1adba8 39: 4c 8b 23 mov (%rbx),%r12 3c: 48 8d 5d 07 lea 0x7(%rbp),%rbx