syzbot


BUG: unable to handle kernel paging request in mld_clear_delrec

Status: upstream: reported on 2025/07/10 11:40
Reported-by: syzbot+46cd85402c8acc577264@syzkaller.appspotmail.com
First crash: 14d, last: 14d
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream general protection fault in mld_clear_delrec net 2 87 12h50m 78d 0/29 upstream: reported on 2025/05/08 01:23

Sample crash report:
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

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/10 11:39 linux-6.1.y 04d1ccaa9c28 956bd956 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in mld_clear_delrec
* Struck through repros no longer work on HEAD.