[syzbot] [lsm?] [keyrings?] kernel BUG in assoc_array_insert (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    4c605260bc60 Merge tag 'x86_urgent_for_v6.4_rc6' of git://..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16c8dcd9280000
kernel config:  https://syzkaller.appspot.com/x/.config?x=3c980bfe8b399968
dashboard link: https://syzkaller.appspot.com/bug?extid=f0d059ae6ba48c088dff
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, 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/ba00476ada42/disk-4c605260.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/24e77bf33514/vmlinux-4c605260.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1671769ce82d/bzImage-4c605260.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f0d059ae6ba48c088dff@xxxxxxxxxxxxxxxxxxxxxxxxx

------------[ cut here ]------------
kernel BUG at lib/assoc_array.c:652!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 895 Comm: kworker/1:2 Not tainted 6.4.0-rc5-syzkaller-00313-g4c605260bc60 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023
Workqueue: afs afs_manage_cell_work
RIP: 0010:assoc_array_insert_into_terminal_node lib/assoc_array.c:652 [inline]
RIP: 0010:assoc_array_insert+0x2472/0x2eb0 lib/assoc_array.c:1000
Code: c1 ea 03 80 3c 02 00 0f 84 c4 fe ff ff e8 a6 de bf fd e9 ba fe ff ff e8 fc 13 6d fd 0f 0b e8 f5 13 6d fd 0f 0b e8 ee 13 6d fd <0f> 0b e8 e7 13 6d fd 0f 0b e8 e0 13 6d fd 0f 0b 4c 89 ee 48 c7 c7
RSP: 0018:ffffc900049af790 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000009 RCX: 0000000000000000
RDX: ffff88801f531dc0 RSI: ffffffff841732f2 RDI: ffff8880575b1458
RBP: ffff8880575b1490 R08: 0000000000000005 R09: 0000000000000010
R10: 0000000000000010 R11: 0000000000094001 R12: ffff88802acb6c90
R13: 000000000000000f R14: ffff88807badaf01 R15: ffff88807980f000
FS:  0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2e321000 CR3: 000000003dd87000 CR4: 0000000000350ee0
Call Trace:
 <TASK>
 __key_link_begin+0xf0/0x250 security/keys/keyring.c:1314
 construct_alloc_key security/keys/request_key.c:407 [inline]
 construct_key_and_link security/keys/request_key.c:502 [inline]
 request_key_and_link+0x7f6/0x1340 security/keys/request_key.c:640
 request_key_tag+0x52/0xc0 security/keys/request_key.c:704
 dns_query+0x2ac/0x790 net/dns_resolver/dns_query.c:128
 afs_dns_query+0x126/0x3a0 fs/afs/addr_list.c:249
 afs_update_cell fs/afs/cell.c:404 [inline]
 afs_manage_cell fs/afs/cell.c:771 [inline]
 afs_manage_cell_work+0xa25/0x1290 fs/afs/cell.c:827
 process_one_work+0x99a/0x15e0 kernel/workqueue.c:2405
 worker_thread+0x67d/0x10c0 kernel/workqueue.c:2552
 kthread+0x344/0x440 kernel/kthread.c:379
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:assoc_array_insert_into_terminal_node lib/assoc_array.c:652 [inline]
RIP: 0010:assoc_array_insert+0x2472/0x2eb0 lib/assoc_array.c:1000
Code: c1 ea 03 80 3c 02 00 0f 84 c4 fe ff ff e8 a6 de bf fd e9 ba fe ff ff e8 fc 13 6d fd 0f 0b e8 f5 13 6d fd 0f 0b e8 ee 13 6d fd <0f> 0b e8 e7 13 6d fd 0f 0b e8 e0 13 6d fd 0f 0b 4c 89 ee 48 c7 c7
RSP: 0018:ffffc900049af790 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000009 RCX: 0000000000000000
RDX: ffff88801f531dc0 RSI: ffffffff841732f2 RDI: ffff8880575b1458
RBP: ffff8880575b1490 R08: 0000000000000005 R09: 0000000000000010
R10: 0000000000000010 R11: 0000000000094001 R12: ffff88802acb6c90
R13: 000000000000000f R14: ffff88807badaf01 R15: ffff88807980f000
FS:  0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb7a79831b8 CR3: 0000000020ac2000 CR4: 0000000000350ee0


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