syzbot

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000013: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000098-0x000000000000009f]
CPU: 0 UID: 0 PID: 52 Comm: kworker/u8:3 Not tainted 6.13.0-syzkaller-04858-g21266b8df522 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: netns cleanup_net
RIP: 0010:__fib6_drop_pcpu_from+0x1fd/0x3d0 net/ipv6/ip6_fib.c:980
Code: 48 c1 e8 03 42 80 3c 20 00 74 08 48 89 ef e8 ba 1d 93 f7 48 8b 6d 00 48 85 ed 74 30 48 81 c5 90 00 00 00 48 89 e8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 ef e8 94 1d 93 f7 48 8b 45 00 4c 39 f0
RSP: 0018:ffffc90000bc6c00 EFLAGS: 00010202
RAX: 0000000000000013 RBX: ffffffff8e2fbb50 RCX: ffff888021ac8000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000098 R08: ffffffff8a704438 R09: 1ffffffff20345d6
R10: dffffc0000000000 R11: fffffbfff20345d7 R12: dffffc0000000000
R13: ffff8880248a8510 R14: ffff8880248a8400 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c335fd7 CR3: 00000000118ae000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 fib6_drop_pcpu_from net/ipv6/ip6_fib.c:1024 [inline]
 fib6_purge_rt+0x193/0x890 net/ipv6/ip6_fib.c:1035
 fib6_del_route net/ipv6/ip6_fib.c:1995 [inline]
 fib6_del+0xe71/0x1600 net/ipv6/ip6_fib.c:2040
 fib6_clean_node+0x2f7/0x5e0 net/ipv6/ip6_fib.c:2202
 fib6_walk_continue+0x658/0x8f0 net/ipv6/ip6_fib.c:2124
 fib6_walk+0x168/0x2b0 net/ipv6/ip6_fib.c:2172
 fib6_clean_tree net/ipv6/ip6_fib.c:2252 [inline]
 __fib6_clean_all+0x31f/0x4b0 net/ipv6/ip6_fib.c:2268
 rt6_sync_down_dev net/ipv6/route.c:4908 [inline]
 rt6_disable_ip+0x170/0x800 net/ipv6/route.c:4913
 addrconf_ifdown+0x15d/0x1bd0 net/ipv6/addrconf.c:3849
 addrconf_notify+0x3cb/0x1020
 notifier_call_chain+0x1a5/0x3f0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2179 [inline]
 call_netdevice_notifiers net/core/dev.c:2193 [inline]
 dev_close_many+0x33c/0x4c0 net/core/dev.c:1717
 unregister_netdevice_many_notify+0x52b/0x2030 net/core/dev.c:11779
 unregister_netdevice_many net/core/dev.c:11875 [inline]
 default_device_exit_batch+0xa1f/0xaa0 net/core/dev.c:12360
 ops_exit_list net/core/net_namespace.c:177 [inline]
 cleanup_net+0x8ad/0xd60 net/core/net_namespace.c:652
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3317
 worker_thread+0x870/0xd30 kernel/workqueue.c:3398
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__fib6_drop_pcpu_from+0x1fd/0x3d0 net/ipv6/ip6_fib.c:980
Code: 48 c1 e8 03 42 80 3c 20 00 74 08 48 89 ef e8 ba 1d 93 f7 48 8b 6d 00 48 85 ed 74 30 48 81 c5 90 00 00 00 48 89 e8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 ef e8 94 1d 93 f7 48 8b 45 00 4c 39 f0
RSP: 0018:ffffc90000bc6c00 EFLAGS: 00010202
RAX: 0000000000000013 RBX: ffffffff8e2fbb50 RCX: ffff888021ac8000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000098 R08: ffffffff8a704438 R09: 1ffffffff20345d6
R10: dffffc0000000000 R11: fffffbfff20345d7 R12: dffffc0000000000
R13: ffff8880248a8510 R14: ffff8880248a8400 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c335fd7 CR3: 00000000118ae000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	48 c1 e8 03          	shr    $0x3,%rax
   4:	42 80 3c 20 00       	cmpb   $0x0,(%rax,%r12,1)
   9:	74 08                	je     0x13
   b:	48 89 ef             	mov    %rbp,%rdi
   e:	e8 ba 1d 93 f7       	call   0xf7931dcd
  13:	48 8b 6d 00          	mov    0x0(%rbp),%rbp
  17:	48 85 ed             	test   %rbp,%rbp
  1a:	74 30                	je     0x4c
  1c:	48 81 c5 90 00 00 00 	add    $0x90,%rbp
  23:	48 89 e8             	mov    %rbp,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 20 00       	cmpb   $0x0,(%rax,%r12,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	48 89 ef             	mov    %rbp,%rdi
  34:	e8 94 1d 93 f7       	call   0xf7931dcd
  39:	48 8b 45 00          	mov    0x0(%rbp),%rax
  3d:	4c 39 f0             	cmp    %r14,%rax