syzbot

Unable to handle kernel paging request at virtual address dfff800000000067
KASAN: null-ptr-deref in range [0x0000000000000338-0x000000000000033f]
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
[dfff800000000067] address between user and kernel address ranges
Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 5706 Comm: syz.1.345 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025
pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : ip_ignore_linkdown include/linux/inetdevice.h:259 [inline]
pc : fib_lookup_good_nhc+0x84/0x360 net/ipv4/fib_trie.c:1413
lr : fib_lookup_good_nhc+0x60/0x360 net/ipv4/fib_trie.c:1410
sp : ffff800022ba6cc0
x29: ffff800022ba6cc0 x28: 0000000000000000 x27: dfff800000000000
x26: 1fffe0001a097686 x25: dfff800000000000 x24: 1fffe000188c2801
x23: 0000000000000338 x22: ffff0000d04bb437 x21: 0000000000000001
x20: ffff800022ba7340 x19: ffff0000d04bb420 x18: 0000000000000000
x17: 0000000000000000 x16: ffff8000082d0e30 x15: 0000000000000002
x14: 0000000000000008 x13: 1ffff00002a180b1 x12: 0000000000ff0100
x11: ff0080001057e64c x10: 0000000000000002 x9 : ffff0000d1590000
x8 : 0000000000000067 x7 : ffff8000105cf328 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000000 x3 : ffff800022ba6e14
x2 : ffff800022ba7340 x1 : 0000000000000000 x0 : 0000000000000000
Call trace:
 ip_ignore_linkdown include/linux/inetdevice.h:259 [inline]
 fib_lookup_good_nhc+0x84/0x360 net/ipv4/fib_trie.c:1413
 nexthop_get_nhc_lookup+0x19c/0x3c8 include/net/nexthop.h:405
 fib_table_lookup+0xe88/0x1798 net/ipv4/fib_trie.c:1590
 fib4_rule_action+0x1d8/0x300 net/ipv4/fib_rules.c:136
 fib_rules_lookup+0x558/0xa64 net/core/fib_rules.c:318
 __fib_lookup+0xe4/0x1c8 net/ipv4/fib_rules.c:93
 fib_lookup+0x70/0x40c include/net/ip_fib.h:377
 ip_route_output_key_hash_rcu+0x220/0x1e3c net/ipv4/route.c:2784
 ip_route_output_key_hash+0x1a8/0x2ec net/ipv4/route.c:2674
 __ip_route_output_key include/net/route.h:137 [inline]
 ip_route_output_flow+0x3c/0x160 net/ipv4/route.c:2904
 ip_route_output_ports include/net/route.h:180 [inline]
 ipip6_tunnel_bind_dev+0x190/0x4ec net/ipv6/sit.c:1108
 ipip6_tunnel_init+0xd4/0x588 net/ipv6/sit.c:1451
 register_netdevice+0x488/0x15cc net/core/dev.c:10130
 ipip6_tunnel_create+0x130/0x330 net/ipv6/sit.c:215
 ipip6_tunnel_locate+0x454/0x63c net/ipv6/sit.c:271
 ipip6_tunnel_add net/ipv6/sit.c:1293 [inline]
 ipip6_tunnel_ctl+0x5a0/0x864 net/ipv6/sit.c:1357
 ip_tunnel_siocdevprivate+0x1bc/0x364 net/ipv4/ip_tunnel.c:1017
 ipip6_tunnel_siocdevprivate+0x240/0x182c net/ipv6/sit.c:1376
 dev_siocdevprivate net/core/dev_ioctl.c:287 [inline]
 dev_ifsioc+0xa68/0xed0 net/core/dev_ioctl.c:406
 dev_ioctl+0x548/0xc8c net/core/dev_ioctl.c:613
 sock_ioctl+0x7a4/0x840 net/socket.c:1248
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl fs/ioctl.c:856 [inline]
 __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856
 __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: 960d6174 f9400268 910ce117 d343fee8 (38796908) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	960d6174 	bl	0xfffffffff83585d0
   4:	f9400268 	ldr	x8, [x19]
   8:	910ce117 	add	x23, x8, #0x338
   c:	d343fee8 	lsr	x8, x23, #3
* 10:	38796908 	ldrb	w8, [x8, x25] <-- trapping instruction