general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017] CPU: 0 PID: 6651 Comm: gfs2_quotad Not tainted 5.15.184-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:do_sync+0x96f/0xc00 fs/gfs2/quota.c:986 Code: 00 fc ff df 80 3c 08 00 74 08 48 89 df e8 29 7f 53 fe 48 8b 1b 48 8d 7b 10 48 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 05 e8 06 7f 53 fe 48 8b 7b 10 48 89 de ba 02 00 04 RSP: 0018:ffffc900032bfb60 EFLAGS: 00010202 RAX: 0000000000000002 RBX: 0000000000000000 RCX: dffffc0000000000 RDX: dffffc0000000000 RSI: ffffffff8a0b11c0 RDI: 0000000000000010 RBP: ffffc900032bfce0 R08: dffffc0000000000 R09: fffffbfff1ff3650 R10: fffffbfff1ff3650 R11: 1ffffffff1ff364f R12: ffff88805e8fb640 R13: 00000000fffffffb R14: ffffffffffffffff R15: ffff888023244200 FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f4f5b0ea000 CR3: 0000000062f74000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: gfs2_quota_sync+0x32c/0x6f0 fs/gfs2/quota.c:1329 quotad_check_timeo fs/gfs2/quota.c:1519 [inline] gfs2_quotad+0x3f6/0x880 fs/gfs2/quota.c:1586 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Modules linked in: ---[ end trace 36e74b4c16da64ab ]--- RIP: 0010:do_sync+0x96f/0xc00 fs/gfs2/quota.c:986 Code: 00 fc ff df 80 3c 08 00 74 08 48 89 df e8 29 7f 53 fe 48 8b 1b 48 8d 7b 10 48 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 05 e8 06 7f 53 fe 48 8b 7b 10 48 89 de ba 02 00 04 RSP: 0018:ffffc900032bfb60 EFLAGS: 00010202 RAX: 0000000000000002 RBX: 0000000000000000 RCX: dffffc0000000000 RDX: dffffc0000000000 RSI: ffffffff8a0b11c0 RDI: 0000000000000010 RBP: ffffc900032bfce0 R08: dffffc0000000000 R09: fffffbfff1ff3650 R10: fffffbfff1ff3650 R11: 1ffffffff1ff364f R12: ffff88805e8fb640 R13: 00000000fffffffb R14: ffffffffffffffff R15: ffff888023244200 FS: 0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f4d9da43ab8 CR3: 000000002a8f7000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess), 3 bytes skipped: 0: df 80 3c 08 00 74 filds 0x7400083c(%rax) 6: 08 48 89 or %cl,-0x77(%rax) 9: df e8 fucomip %st(0),%st b: 29 7f 53 sub %edi,0x53(%rdi) e: fe 48 8b decb -0x75(%rax) 11: 1b 48 8d sbb -0x73(%rax),%ecx 14: 7b 10 jnp 0x26 16: 48 89 f8 mov %rdi,%rax 19: 48 c1 e8 03 shr $0x3,%rax 1d: 48 b9 00 00 00 00 00 movabs $0xdffffc0000000000,%rcx 24: fc ff df * 27: 80 3c 08 00 cmpb $0x0,(%rax,%rcx,1) <-- trapping instruction 2b: 74 05 je 0x32 2d: e8 06 7f 53 fe call 0xfe537f38 32: 48 8b 7b 10 mov 0x10(%rbx),%rdi 36: 48 89 de mov %rbx,%rsi 39: ba .byte 0xba 3a: 02 00 add (%rax),%al 3c: 04 .byte 0x4