BUG: unable to handle kernel paging request in rt6_find_cached

Kernel	Title	Rank 🛈	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	general protection fault in rt6_find_cached_rt net	2				3	180d	221d	0/29	auto-obsoleted due to no activity on 2025/09/22 19:38
Unable to handle kernel paging request at virtual address dfff80000000000c
KASAN: null-ptr-deref in range [0x0000000000000060-0x0000000000000067]
Mem abort info:
  ESR = 0x0000000096000006
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x06: level 2 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000006
  CM = 0, WnR = 0
[dfff80000000000c] address between user and kernel address ranges
Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 7776 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025
pstate: 62400005 (nZCv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : fib6_nh_get_excptn_bucket net/ipv6/route.c:1656 [inline]
pc : rt6_find_cached_rt+0xc4/0x27c net/ipv6/route.c:1851
lr : rt6_find_cached_rt+0x98/0x27c net/ipv6/route.c:1847
sp : ffff8000080169b0
x29: ffff8000080169c0 x28: 1ffff00001002d52 x27: 1ffff00001002d53
x26: dfff800000000000 x25: 0000000000000060 x24: 0000000000000000
x23: ffff800008017298 x22: ffff800017a8a000 x21: ffff800008016a98
x20: ffff800008016a90 x19: ffff800008017288 x18: 0000000000000000
x17: 0000000000000000 x16: ffff8000082d10fc x15: 0000000000000000
x14: 000000000000000a x13: 1ffff00002a180b1 x12: 0000000000ff0100
x11: ff008000107a3210 x10: 0000000000000000 x9 : ffff0000d3098000
x8 : 000000000000000c x7 : ffff8000105abba0 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000002
x2 : ffff800008017298 x1 : 0000000000000000 x0 : 0000000000000000
Call trace:
 fib6_nh_get_excptn_bucket net/ipv6/route.c:1656 [inline]
 rt6_find_cached_rt+0xc4/0x27c net/ipv6/route.c:1851
 ip6_pol_route+0x24c/0x1024 net/ipv6/route.c:2266
 ip6_pol_route_output+0x60/0x94 net/ipv6/route.c:2634
 pol_lookup_func include/net/ip6_fib.h:579 [inline]
 fib6_rule_lookup+0x258/0x4a8 net/ipv6/fib6_rules.c:121
 ip6_route_output_flags_noref+0x250/0x314 net/ipv6/route.c:2666
 ip6_route_output_flags+0xe4/0x368 net/ipv6/route.c:2679
 ip6_route_output include/net/ip6_route.h:98 [inline]
 ip6_dst_lookup_tail+0x168/0x12c0 net/ipv6/ip6_output.c:1124
 ip6_dst_lookup_flow+0x54/0xe0 net/ipv6/ip6_output.c:1255
 geneve_get_v6_dst+0x648/0x954 drivers/net/geneve.c:901
 geneve6_xmit_skb drivers/net/geneve.c:1038 [inline]
 geneve_xmit+0x970/0x2f18 drivers/net/geneve.c:1122
 __netdev_start_xmit include/linux/netdevice.h:4896 [inline]
 netdev_start_xmit include/linux/netdevice.h:4910 [inline]
 xmit_one net/core/dev.c:3670 [inline]
 dev_hard_start_xmit+0x244/0x8e0 net/core/dev.c:3686
 __dev_queue_xmit+0x155c/0x309c net/core/dev.c:4346
 dev_queue_xmit include/linux/netdevice.h:3051 [inline]
 neigh_resolve_output+0x550/0x650 net/core/neighbour.c:1568
 neigh_output include/net/neighbour.h:545 [inline]
 ip6_finish_output2+0xd60/0x1844 net/ipv6/ip6_output.c:138
 __ip6_finish_output net/ipv6/ip6_output.c:205 [inline]
 ip6_finish_output+0x594/0x930 net/ipv6/ip6_output.c:216
 NF_HOOK_COND include/linux/netfilter.h:291 [inline]
 ip6_output+0x274/0x500 net/ipv6/ip6_output.c:237
 dst_output include/net/dst.h:453 [inline]
 NF_HOOK include/linux/netfilter.h:302 [inline]
 ndisc_send_skb+0xc38/0x1680 net/ipv6/ndisc.c:513
 ndisc_send_rs+0x378/0x514 net/ipv6/ndisc.c:723
 addrconf_rs_timer+0x2f4/0x574 net/ipv6/addrconf.c:3979
 call_timer_fn+0x1b8/0x964 kernel/time/timer.c:1700
 expire_timers kernel/time/timer.c:1751 [inline]
 __run_timers+0x468/0x6d8 kernel/time/timer.c:2022
 run_timer_softirq+0x7c/0x114 kernel/time/timer.c:2035
 handle_softirqs+0x318/0xc6c kernel/softirq.c:596
 __do_softirq+0x14/0x20 kernel/softirq.c:630
 ____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:80
 call_on_irq_stack+0x30/0x48 arch/arm64/kernel/entry.S:897
 do_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:85
 invoke_softirq kernel/softirq.c:477 [inline]
 __irq_exit_rcu+0x23c/0x43c kernel/softirq.c:679
 irq_exit_rcu+0x14/0x84 kernel/softirq.c:691
 __el1_irq arch/arm64/kernel/entry-common.c:472 [inline]
 el1_interrupt+0x38/0x54 arch/arm64/kernel/entry-common.c:486
 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:491
 el1h_64_irq+0x64/0x68 arch/arm64/kernel/entry.S:581
 copy_pte_range mm/memory.c:1069 [inline]
 copy_pmd_range mm/memory.c:1177 [inline]
 copy_pud_range mm/memory.c:1214 [inline]
 copy_p4d_range mm/memory.c:1238 [inline]
 copy_page_range+0xaec/0x2910 mm/memory.c:1336
 dup_mmap kernel/fork.c:697 [inline]
 dup_mm kernel/fork.c:1541 [inline]
 copy_mm+0xac8/0x11e0 kernel/fork.c:1590
 copy_process+0x1618/0x3670 kernel/fork.c:2351
 kernel_clone+0x1d8/0x8fc kernel/fork.c:2757
 __do_sys_clone kernel/fork.c:2898 [inline]
 __se_sys_clone kernel/fork.c:2866 [inline]
 __arm64_sys_clone+0x140/0x19c kernel/fork.c:2866
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
Code: 9604d0e4 f9400288 91018119 d343ff28 (387a6908) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	9604d0e4 	bl	0xfffffffff8134390
   4:	f9400288 	ldr	x8, [x20]
   8:	91018119 	add	x25, x8, #0x60
   c:	d343ff28 	lsr	x8, x25, #3
* 10:	387a6908 	ldrb	w8, [x8, x26] <-- trapping instruction