syzbot


BUG: unable to handle kernel paging request in ip6_mc_clear_src

Status: upstream: reported on 2025/08/05 15:21
Reported-by: syzbot+a3c14bf2e2a06815bd48@syzkaller.appspotmail.com
First crash: 3d08h, last: 3d08h
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream general protection fault in ip6_mc_clear_src (2) net 2 62 9h49m 65d 0/29 upstream: reported on 2025/06/04 19:25
upstream general protection fault in ip6_mc_clear_src net 2 2 134d 144d 0/29 closed as invalid on 2025/04/18 16:40

Sample crash report:
Unable to handle kernel paging request at virtual address dfff80001fffe000
Mem abort info:
  ESR = 0x0000000096000007
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x07: level 3 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000007
  CM = 0, WnR = 0
[dfff80001fffe000] address between user and kernel address ranges
Internal error: Oops: 0000000096000007 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 4166 Comm: kworker/u4:10 Not tainted 5.15.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: netns cleanup_net
pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : ip6_mc_clear_src+0x120/0x4b8 net/ipv6/mcast.c:2557
lr : ip6_mc_clear_src+0x114/0x4b8 net/ipv6/mcast.c:2557
sp : ffff80001b8b7240
x29: ffff80001b8b7240 x28: 1fffe00019ee6c02 x27: 1fffe00019ee6c05
x26: dfff800000000000 x25: 0000000000000001 x24: ffff800012dc5960
x23: ffff8000165b2000 x22: 00000000ffff0000 x21: ffff0000cf736010
x20: ffff0000cf736028 x19: ffff0000cf736000 x18: 0000000000000000
x17: 0000000000000000 x16: ffff8000082bf708 x15: 000000000000030a
x14: 00000000ffff8000 x13: 1ffff0000282e06b x12: 0000000000ff0100
x11: 0000000000000000 x10: 0000000000000000 x9 : ffff8000101cebc8
x8 : 000000001fffe000 x7 : 0000000000000000 x6 : 0000000000000000
x5 : 0000000000000080 x4 : 0000000000000000 x3 : 0000000000000010
x2 : 0000000000000006 x1 : 0000000000000001 x0 : 0000000000000000
Call trace:
 ip6_mc_clear_src+0x120/0x4b8 net/ipv6/mcast.c:2557
 __ipv6_dev_mc_dec+0x29c/0x320 net/ipv6/mcast.c:979
 addrconf_leave_solict net/ipv6/addrconf.c:2214 [inline]
 __ipv6_ifa_notify+0x5e8/0xbf4 net/ipv6/addrconf.c:6202
 addrconf_ifdown+0xc6c/0x1688 net/ipv6/addrconf.c:3900
 addrconf_notify+0x2f4/0xc6c net/ipv6/addrconf.c:-1
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0xd4/0x164 kernel/notifier.c:391
 call_netdevice_notifiers_info net/core/dev.c:2049 [inline]
 call_netdevice_notifiers_extack net/core/dev.c:2061 [inline]
 call_netdevice_notifiers net/core/dev.c:2075 [inline]
 unregister_netdevice_many+0xe10/0x17d0 net/core/dev.c:11134
 default_device_exit_batch+0x444/0x4a4 net/core/dev.c:11667
 ops_exit_list net/core/net_namespace.c:177 [inline]
 cleanup_net+0x644/0xa98 net/core/net_namespace.c:635
 process_one_work+0x79c/0x1140 kernel/workqueue.c:2310
 worker_thread+0x8f4/0x101c kernel/workqueue.c:2457
 kthread+0x374/0x454 kernel/kthread.c:334
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:855
Code: 960aaa0f 14000002 960aaa0d d343fec8 (387a6908) 
---[ end trace 88970e3d4acd26aa ]---
----------------
Code disassembly (best guess):
   0:	960aaa0f 	bl	0xfffffffff82aa83c
   4:	14000002 	b	0xc
   8:	960aaa0d 	bl	0xfffffffff82aa83c
   c:	d343fec8 	lsr	x8, x22, #3
* 10:	387a6908 	ldrb	w8, [x8, x26] <-- trapping instruction

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/05 15:21 linux-5.15.y c79648372d02 37880f40 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 BUG: unable to handle kernel paging request in ip6_mc_clear_src
* Struck through repros no longer work on HEAD.