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BUG: KASAN: use-after-free in atomic_read include/asm-generic/atomic-instrumented.h:26 [inline]
BUG: KASAN: use-after-free in atomic_fetch_add_unless include/linux/atomic-fallback.h:1086 [inline]
BUG: KASAN: use-after-free in atomic_add_unless include/linux/atomic-fallback.h:1111 [inline]
BUG: KASAN: use-after-free in atomic_inc_not_zero include/linux/atomic-fallback.h:1127 [inline]
BUG: KASAN: use-after-free in dst_hold_safe include/net/dst.h:297 [inline]
BUG: KASAN: use-after-free in ip6_hold_safe+0xad/0x380 net/ipv6/route.c:1050
Read of size 4 at addr ffff8880721cced4 by task kworker/0:26/18262

CPU: 0 PID: 18262 Comm: kworker/0:26 Not tainted 5.2.0-rc1+ #7
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events rt6_probe_deferred
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:188
 __kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 kasan_report+0x12/0x20 mm/kasan/common.c:614
 check_memory_region_inline mm/kasan/generic.c:185 [inline]
 check_memory_region+0x123/0x190 mm/kasan/generic.c:191
 kasan_check_read+0x11/0x20 mm/kasan/common.c:94
 atomic_read include/asm-generic/atomic-instrumented.h:26 [inline]
 atomic_fetch_add_unless include/linux/atomic-fallback.h:1086 [inline]
 atomic_add_unless include/linux/atomic-fallback.h:1111 [inline]
 atomic_inc_not_zero include/linux/atomic-fallback.h:1127 [inline]
 dst_hold_safe include/net/dst.h:297 [inline]
 ip6_hold_safe+0xad/0x380 net/ipv6/route.c:1050
 rt6_get_pcpu_route net/ipv6/route.c:1277 [inline]
 ip6_pol_route+0x336/0x1050 net/ipv6/route.c:2028
 ip6_pol_route_input+0x65/0x80 net/ipv6/route.c:2047
 fib6_rule_lookup+0x133/0x5a0 net/ipv6/fib6_rules.c:116
 ip6_route_input_lookup+0xb7/0xd0 net/ipv6/route.c:2059
 ip6_route_input+0x5e2/0x9e0 net/ipv6/route.c:2194
 ip6_rcv_finish_core.isra.0+0x174/0x590 net/ipv6/ip6_input.c:67
 ip6_rcv_finish+0x17a/0x310 net/ipv6/ip6_input.c:78
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 ipv6_rcv+0x10e/0x420 net/ipv6/ip6_input.c:276
 __netif_receive_skb_one_core+0x113/0x1a0 net/core/dev.c:4990
 __netif_receive_skb+0x2c/0x1d0 net/core/dev.c:5104
 process_backlog+0x206/0x750 net/core/dev.c:5944
 napi_poll net/core/dev.c:6367 [inline]
 net_rx_action+0x4f5/0x1070 net/core/dev.c:6433
 __do_softirq+0x25c/0x94c kernel/softirq.c:293
 do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1040
 </IRQ>
 do_softirq.part.0+0x11a/0x170 kernel/softirq.c:338
 do_softirq kernel/softirq.c:330 [inline]
 __local_bh_enable_ip+0x211/0x270 kernel/softirq.c:190
 local_bh_enable include/linux/bottom_half.h:32 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:684 [inline]
 ip6_finish_output2+0x10a0/0x2550 net/ipv6/ip6_output.c:121
 ip6_finish_output+0x56d/0xc20 net/ipv6/ip6_output.c:154
 NF_HOOK_COND include/linux/netfilter.h:294 [inline]
 ip6_output+0x235/0x7f0 net/ipv6/ip6_output.c:171
 dst_output include/net/dst.h:433 [inline]
 NF_HOOK include/linux/netfilter.h:305 [inline]
 ndisc_send_skb+0xf29/0x14a0 net/ipv6/ndisc.c:508
 ndisc_send_ns+0x3a9/0x850 net/ipv6/ndisc.c:650
 rt6_probe_deferred+0xe3/0x1a0 net/ipv6/route.c:543
 process_one_work+0x989/0x1790 kernel/workqueue.c:2269
 worker_thread+0x98/0xe40 kernel/workqueue.c:2415
 kthread+0x354/0x420 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

The buggy address belongs to the page:
page:ffffea0001c87300 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x0
flags: 0x1fffc0000000000()
raw: 01fffc0000000000 ffffea0001bc7688 ffffea0002237b48 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffff7f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880721ccd80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880721cce00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8880721cce80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                 ^
 ffff8880721ccf00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880721ccf80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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