[v6.1] BUG: unable to handle kernel paging request in mld_clear_delrec

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 04d1ccaa9c28 Linux 6.1.143
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=115e40f0580000
kernel config: https://syzkaller.appspot.com/x/.config?x=30fae84d50729cf
dashboard link: https://syzkaller.appspot.com/bug?extid=46cd85402c8acc577264
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
userspace arch: arm64

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6be65a5e6fec/disk-04d1ccaa.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/52fda42cf9c4/vmlinux-04d1ccaa.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0491d42b7947/Image-04d1ccaa.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+46cd85...@syzkaller.appspotmail.com

Unable to handle kernel paging request at virtual address 00000000ffff0000
Mem abort info:
ESR = 0x0000000096000004
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x04: level 0 translation fault
Data abort info:
ISV = 0, ISS = 0x00000004
CM = 0, WnR = 0
user pgtable: 4k pages, 48-bit VAs, pgdp=000000013124e000
[00000000ffff0000] pgd=0000000000000000, p4d=0000000000000000
Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 4431 Comm: kworker/1:6 Not tainted 6.1.143-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: events ser_release
pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : mld_clear_delrec+0x37c/0x5f4 net/ipv6/mcast.c:834
lr : mld_clear_delrec+0x360/0x5f4 net/ipv6/mcast.c:834
sp : ffff800021617590
x29: ffff800021617590 x28: ffff800017a77000 x27: ffff0000f4370c00
x26: dfff800000000000 x25: 0000000000000001 x24: ffff800017a77000
x23: 0000000000000001 x22: 00000000ffff0000 x21: ffff800013a8a160
x20: ffff800013a8a140 x19: ffff0000f3f91000 x18: ffff800011aabce0
x17: ffff8000181e6000 x16: ffff8000082d0f50 x15: ffff800017cc6fc0
x14: ffff0000ce01a658 x13: 1ffff00002a160b1 x12: 0000000000ff0100
x11: ff008000108038e8 x10: 0000000000000000 x9 : ffff8000108038e8
x8 : 0000000000000000 x7 : ffff8000108030c8 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000001 x3 : ffff8000082c96f4
x2 : ffff0000ce019bc0 x1 : 0000000000000001 x0 : 0000000000000000
Call trace:
mld_clear_delrec+0x37c/0x5f4 net/ipv6/mcast.c:834
ipv6_mc_destroy_dev+0x50/0x508 net/ipv6/mcast.c:2799
addrconf_ifdown+0x1188/0x15dc net/ipv6/addrconf.c:3947
addrconf_notify+0x2f4/0xca8 net/ipv6/addrconf.c:-1
notifier_call_chain kernel/notifier.c:87 [inline]
raw_notifier_call_chain+0xd4/0x164 kernel/notifier.c:455
call_netdevice_notifiers_info net/core/dev.c:2001 [inline]
call_netdevice_notifiers_extack net/core/dev.c:2039 [inline]
call_netdevice_notifiers net/core/dev.c:2053 [inline]
unregister_netdevice_many+0xe2c/0x1740 net/core/dev.c:10978
unregister_netdevice_queue+0x2ac/0x2f8 net/core/dev.c:10909
unregister_netdevice include/linux/netdevice.h:3075 [inline]
ser_release+0x16c/0x1ec drivers/net/caif/caif_serial.c:310
process_one_work+0x7f4/0x13a8 kernel/workqueue.c:2292
worker_thread+0x8c8/0xfbc kernel/workqueue.c:2439
kthread+0x250/0x2d8 kernel/kthread.c:376
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:849
Code: 387a6908 34000068 aa1603e0 96034b16 (f84306d7)
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
0: 387a6908 ldrb w8, [x8, x26]
4: 34000068 cbz w8, 0x10
8: aa1603e0 mov x0, x22
c: 96034b16 bl 0xfffffffff80d2c64
* 10: f84306d7 ldr x23, [x22], #48 <-- trapping instruction


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[syzbot]

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