[v5.15] general protection fault in __d_add

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 2ddbd0f967b3 Linux 5.15.102
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=11e411e2c80000
kernel config: https://syzkaller.appspot.com/x/.config?x=fec083380faceb1e
dashboard link: https://syzkaller.appspot.com/bug?extid=63bf19771097ae549d0b
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/156d2aa91f3c/disk-2ddbd0f9.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f0e97f5be5fb/vmlinux-2ddbd0f9.xz
kernel image: https://storage.googleapis.com/syzbot-assets/20d0a55a041d/bzImage-2ddbd0f9.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+63bf19...@syzkaller.appspotmail.com

general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 0 PID: 5147 Comm: syz-executor.3 Not tainted 5.15.102-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
RIP: 0010:d_flags_for_inode fs/dcache.c:1954 [inline]
RIP: 0010:__d_add+0x5c6/0x7f0 fs/dcache.c:2706
Code: 00 fc ff df 80 3c 08 00 74 08 48 89 df e8 42 ef ed ff 48 8b 1b 48 83 c3 08 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 1c ef ed ff 48 83 3b 00 0f 85 b6 01
RSP: 0018:ffffc9000375f8a0 EFLAGS: 00010202
RAX: 0000000000000001 RBX: 0000000000000008 RCX: dffffc0000000000
RDX: ffff88801c003a00 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000008 R08: ffffffff81dc0ffb R09: ffff888037d0ba20
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff88803b8970f2
R13: 0000000000000000 R14: ffff888037d0b8f8 R15: 1ffff11007712e1e
FS: 00007fc04ead6700(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb6fdafe718 CR3: 0000000018cc2000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
d_splice_alias+0x10f/0x330 fs/dcache.c:3100
lookup_open fs/namei.c:3312 [inline]
open_last_lookups fs/namei.c:3404 [inline]
path_openat+0x10d2/0x2ee0 fs/namei.c:3612
do_filp_open+0x21c/0x460 fs/namei.c:3642
do_sys_openat2+0x13b/0x500 fs/open.c:1211
do_sys_open fs/open.c:1227 [inline]
__do_sys_creat fs/open.c:1301 [inline]
__se_sys_creat fs/open.c:1295 [inline]
__x64_sys_creat+0x11f/0x160 fs/open.c:1295
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fc0505640f9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fc04ead6168 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007fc050683f80 RCX: 00007fc0505640f9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000200000c0
RBP: 00007fc0505bfb39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe950ca04f R14: 00007fc04ead6300 R15: 0000000000022000
</TASK>
Modules linked in:
---[ end trace 4b8e3ff7e5b0d6c2 ]---
RIP: 0010:d_flags_for_inode fs/dcache.c:1954 [inline]
RIP: 0010:__d_add+0x5c6/0x7f0 fs/dcache.c:2706
Code: 00 fc ff df 80 3c 08 00 74 08 48 89 df e8 42 ef ed ff 48 8b 1b 48 83 c3 08 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 1c ef ed ff 48 83 3b 00 0f 85 b6 01
RSP: 0018:ffffc9000375f8a0 EFLAGS: 00010202
RAX: 0000000000000001 RBX: 0000000000000008 RCX: dffffc0000000000
RDX: ffff88801c003a00 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000008 R08: ffffffff81dc0ffb R09: ffff888037d0ba20
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff88803b8970f2
R13: 0000000000000000 R14: ffff888037d0b8f8 R15: 1ffff11007712e1e
FS: 00007fc04ead6700(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb6fdafe718 CR3: 0000000018cc2000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 4 bytes skipped:
0: 80 3c 08 00 cmpb $0x0,(%rax,%rcx,1)
4: 74 08 je 0xe
6: 48 89 df mov %rbx,%rdi
9: e8 42 ef ed ff callq 0xffedef50
e: 48 8b 1b mov (%rbx),%rbx
11: 48 83 c3 08 add $0x8,%rbx
15: 48 89 d8 mov %rbx,%rax
18: 48 c1 e8 03 shr $0x3,%rax
1c: 48 b9 00 00 00 00 00 movabs $0xdffffc0000000000,%rcx
23: fc ff df
* 26: 80 3c 08 00 cmpb $0x0,(%rax,%rcx,1) <-- trapping instruction
2a: 74 08 je 0x34
2c: 48 89 df mov %rbx,%rdi
2f: e8 1c ef ed ff callq 0xffedef50
34: 48 83 3b 00 cmpq $0x0,(%rbx)
38: 0f .byte 0xf
39: 85 .byte 0x85
3a: b6 01 mov $0x1,%dh


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.