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BUG: KASAN: slab-out-of-bounds in fib6_nh_get_excptn_bucket+0x198/0x1b0 net/ipv6/route.c:1591
Read of size 8 at addr ffff88808be8b6f8 by task syz-executor.1/17961

CPU: 1 PID: 17961 Comm: syz-executor.1 Not tainted 5.3.0+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374
 __kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506
 kasan_report+0x12/0x17 mm/kasan/common.c:634
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132
 fib6_nh_get_excptn_bucket+0x198/0x1b0 net/ipv6/route.c:1591
 fib6_nh_flush_exceptions+0x37/0x2d0 net/ipv6/route.c:1719
 fib6_nh_release+0x84/0x3a0 net/ipv6/route.c:3501
 fib6_info_destroy_rcu+0x11e/0x150 net/ipv6/ip6_fib.c:174
 __rcu_reclaim kernel/rcu/rcu.h:222 [inline]
 rcu_do_batch kernel/rcu/tree.c:2157 [inline]
 rcu_core+0x581/0x1560 kernel/rcu/tree.c:2377
 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2386
 __do_softirq+0x262/0x98c kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x19b/0x1e0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1137
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830
 </IRQ>
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:756 [inline]
RIP: 0010:lock_acquire+0x20b/0x410 kernel/locking/lockdep.c:4490
Code: 94 08 00 00 00 00 00 00 48 c1 e8 03 80 3c 10 00 0f 85 d3 01 00 00 48 83 3d b1 e0 99 07 00 0f 84 53 01 00 00 48 8b 7d c8 57 9d <0f> 1f 44 00 00 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 65 8b
RSP: 0018:ffff8880930cf6d0 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff11e630c RBX: ffff888098b36280 RCX: ffffffff8158e6a3
RDX: dffffc0000000000 RSI: 0000000000000008 RDI: 0000000000000282
RBP: ffff8880930cf718 R08: 0000000000007ed7 R09: ffffffff8a771f78
R10: ffff888098b36b40 R11: ffff888098b36280 R12: ffffffff890a38a0
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 __mutex_lock_common kernel/locking/mutex.c:956 [inline]
 __mutex_lock+0x156/0x13c0 kernel/locking/mutex.c:1103
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118
 kernfs_add_one+0x51/0x4d0 fs/kernfs/dir.c:774
 kernfs_create_link+0x1b8/0x250 fs/kernfs/symlink.c:49
 sysfs_do_create_link_sd.isra.0+0x90/0x130 fs/sysfs/symlink.c:44
 sysfs_do_create_link fs/sysfs/symlink.c:80 [inline]
 sysfs_create_link+0x65/0xc0 fs/sysfs/symlink.c:92
 device_add_class_symlinks drivers/base/core.c:1959 [inline]
 device_add+0x75c/0x17a0 drivers/base/core.c:2167
 netdev_register_kobject+0x183/0x3b0 net/core/net-sysfs.c:1746
 register_netdevice+0x875/0x1000 net/core/dev.c:8781
 tun_set_iff drivers/net/tun.c:2838 [inline]
 __tun_chr_ioctl+0x2da7/0x3f30 drivers/net/tun.c:3075
 tun_chr_ioctl+0x2b/0x40 drivers/net/tun.c:3355
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:509 [inline]
 do_vfs_ioctl+0xdb6/0x13e0 fs/ioctl.c:696
 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713
 __do_sys_ioctl fs/ioctl.c:720 [inline]
 __se_sys_ioctl fs/ioctl.c:718 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459a29
Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fc321de2c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459a29
RDX: 0000000020000000 RSI: 00000000400454ca RDI: 0000000000000005
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fc321de36d4
R13: 00000000004c458a R14: 00000000004d89e0 R15: 00000000ffffffff

Allocated by task 17960:
 save_stack+0x23/0x90 mm/kasan/common.c:69
 set_track mm/kasan/common.c:77 [inline]
 __kasan_kmalloc mm/kasan/common.c:510 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:483
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:524
 kmem_cache_alloc_trace+0x158/0x790 mm/slab.c:3550
 kmalloc include/linux/slab.h:552 [inline]
 kzalloc include/linux/slab.h:686 [inline]
 fib6_info_alloc+0xb6/0x1b0 net/ipv6/ip6_fib.c:154
 ip6_route_info_create+0x2fe/0x1530 net/ipv6/route.c:3603
 ip6_route_add+0x27/0xc0 net/ipv6/route.c:3695
 inet6_rtm_newroute+0x16c/0x180 net/ipv6/route.c:5263
 rtnetlink_rcv_msg+0x463/0xb00 net/core/rtnetlink.c:5223
 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477
 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5241
 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
 netlink_unicast+0x531/0x710 net/netlink/af_netlink.c:1328
 netlink_sendmsg+0x8a5/0xd60 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:637 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:657
 ___sys_sendmsg+0x803/0x920 net/socket.c:2311
 __sys_sendmsg+0x105/0x1d0 net/socket.c:2356
 __do_sys_sendmsg net/socket.c:2365 [inline]
 __se_sys_sendmsg net/socket.c:2363 [inline]
 __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2363
 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 9:
 save_stack+0x23/0x90 mm/kasan/common.c:69
 set_track mm/kasan/common.c:77 [inline]
 kasan_set_free_info mm/kasan/common.c:332 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:471
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:480
 __cache_free mm/slab.c:3425 [inline]
 kfree+0x10a/0x2c0 mm/slab.c:3756
 neigh_parms_destroy net/core/neighbour.c:1669 [inline]
 neigh_parms_put net/core/neighbour.c:824 [inline]
 neigh_rcu_free_parms+0x42/0x50 net/core/neighbour.c:1650
 __rcu_reclaim kernel/rcu/rcu.h:222 [inline]
 rcu_do_batch kernel/rcu/tree.c:2157 [inline]
 rcu_core+0x581/0x1560 kernel/rcu/tree.c:2377
 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2386
 __do_softirq+0x262/0x98c kernel/softirq.c:292

The buggy address belongs to the object at ffff88808be8b600
 which belongs to the cache kmalloc-192 of size 192
The buggy address is located 56 bytes to the right of
 192-byte region [ffff88808be8b600, ffff88808be8b6c0)
The buggy address belongs to the page:
page:ffffea00022fa2c0 refcount:1 mapcount:0 mapping:ffff8880aa400000 index:0x0
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea000272a8c8 ffff8880aa401148 ffff8880aa400000
raw: 0000000000000000 ffff88808be8b000 0000000100000010 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88808be8b580: 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88808be8b600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88808be8b680: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc
                                                                ^
 ffff88808be8b700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88808be8b780: 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc
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