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BUG: KASAN: use-after-free in atomic_read include/asm-generic/atomic-instrumented.h:21 [inline]
BUG: KASAN: use-after-free in refcount_inc_not_zero_checked+0x91/0x2e0 lib/refcount.c:120
Read of size 4 at addr ffff88808c3db3c0 by task syz-executor5/25366

CPU: 0 PID: 25366 Comm: syz-executor5 Not tainted 5.0.0-rc3+ #40
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1db/0x2d0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187
 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 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:100
 atomic_read include/asm-generic/atomic-instrumented.h:21 [inline]
 refcount_inc_not_zero_checked+0x91/0x2e0 lib/refcount.c:120
 refcount_inc_checked+0x17/0x70 lib/refcount.c:153
 sock_hold include/net/sock.h:647 [inline]
 nr_release+0x62/0x3c0 net/netrom/af_netrom.c:523
 __sock_release+0xd3/0x250 net/socket.c:579
 sock_close+0x1b/0x30 net/socket.c:1141
 __fput+0x3c5/0xb10 fs/file_table.c:278
 ____fput+0x16/0x20 fs/file_table.c:309
 task_work_run+0x1f4/0x2b0 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0xad7/0x26e0 kernel/exit.c:867
 do_group_exit+0x177/0x430 kernel/exit.c:971
 get_signal+0x8b4/0x19b0 kernel/signal.c:2517
 do_signal+0x91/0x1ea0 arch/x86/kernel/signal.c:816
 exit_to_usermode_loop+0x2f7/0x3b0 arch/x86/entry/common.c:162
 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
 do_syscall_64+0x696/0x800 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x458099
Code: 6d 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 3b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fe4f1e76cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 000000000073bfa8 RCX: 0000000000458099
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000073bfa8
RBP: 000000000073bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000073bfac
R13: 00007ffda9a8268f R14: 00007fe4f1e779c0 R15: 0000000000000001

Allocated by task 27943:
 save_stack+0x45/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 __kasan_kmalloc mm/kasan/common.c:496 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:469
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:504
 __do_kmalloc_node mm/slab.c:3673 [inline]
 __kmalloc_node_track_caller+0x4e/0x70 mm/slab.c:3687
 __kmalloc_reserve.isra.0+0x40/0xe0 net/core/skbuff.c:140
 __alloc_skb+0x12d/0x730 net/core/skbuff.c:208
 alloc_skb include/linux/skbuff.h:1011 [inline]
 alloc_skb_with_frags+0xef/0x720 net/core/skbuff.c:5283
 sock_alloc_send_pskb+0x8c9/0xad0 net/core/sock.c:2091
 sock_alloc_send_skb+0x32/0x40 net/core/sock.c:2108
 __ip6_append_data.isra.0+0x2556/0x3f20 net/ipv6/ip6_output.c:1443
 ip6_append_data+0x1bd/0x2e0 net/ipv6/ip6_output.c:1619
 icmp6_send+0x1d94/0x2d20 net/ipv6/icmp.c:578
 icmpv6_send+0x17e/0x310 net/ipv6/ip6_icmp.c:43
 ip6_link_failure+0x97/0x6d0 net/ipv6/route.c:2231
 dst_link_failure include/net/dst.h:427 [inline]
 ip6_tnl_xmit+0x463/0x38c0 net/ipv6/ip6_tunnel.c:1227
 ip6ip6_tnl_xmit net/ipv6/ip6_tunnel.c:1383 [inline]
 ip6_tnl_start_xmit+0xa03/0x2560 net/ipv6/ip6_tunnel.c:1409
 __netdev_start_xmit include/linux/netdevice.h:4382 [inline]
 netdev_start_xmit include/linux/netdevice.h:4391 [inline]
 xmit_one net/core/dev.c:3278 [inline]
 dev_hard_start_xmit+0x261/0xc70 net/core/dev.c:3294
 __dev_queue_xmit+0x2f8a/0x3a60 net/core/dev.c:3864
 dev_queue_xmit+0x18/0x20 net/core/dev.c:3897
 neigh_direct_output+0x16/0x20 net/core/neighbour.c:1516
 neigh_output include/net/neighbour.h:508 [inline]
 ip6_finish_output2+0xc56/0x28e0 net/ipv6/ip6_output.c:120
 ip6_fragment+0x2a70/0x3780 net/ipv6/ip6_output.c:727
 ip6_finish_output+0x6aa/0xc30 net/ipv6/ip6_output.c:152
 NF_HOOK_COND include/linux/netfilter.h:278 [inline]
 ip6_output+0x23c/0xa00 net/ipv6/ip6_output.c:171
 dst_output include/net/dst.h:444 [inline]
 ip6_local_out+0xc4/0x1b0 net/ipv6/output_core.c:176
 ip6_send_skb+0xbb/0x350 net/ipv6/ip6_output.c:1727
 ip6_push_pending_frames+0xc8/0xf0 net/ipv6/ip6_output.c:1747
 rawv6_push_pending_frames net/ipv6/raw.c:615 [inline]
 rawv6_sendmsg+0x39e6/0x49e0 net/ipv6/raw.c:945
 inet_sendmsg+0x1af/0x740 net/ipv4/af_inet.c:798
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg+0xdd/0x130 net/socket.c:631
 sock_write_iter+0x379/0x5e0 net/socket.c:900
 call_write_iter include/linux/fs.h:1862 [inline]
 new_sync_write fs/read_write.c:474 [inline]
 __vfs_write+0x764/0xb40 fs/read_write.c:487
 vfs_write+0x20c/0x580 fs/read_write.c:549
 ksys_write+0x105/0x260 fs/read_write.c:598
 __do_sys_write fs/read_write.c:610 [inline]
 __se_sys_write fs/read_write.c:607 [inline]
 __x64_sys_write+0x73/0xb0 fs/read_write.c:607
 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 27943:
 save_stack+0x45/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:458
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:466
 __cache_free mm/slab.c:3487 [inline]
 kfree+0xcf/0x230 mm/slab.c:3806
 skb_free_head+0x93/0xb0 net/core/skbuff.c:553
 skb_release_data+0x6ea/0x970 net/core/skbuff.c:573
 skb_release_all+0x4d/0x60 net/core/skbuff.c:627
 __kfree_skb net/core/skbuff.c:641 [inline]
 kfree_skb net/core/skbuff.c:659 [inline]
 kfree_skb+0x199/0x580 net/core/skbuff.c:653
 icmpv6_rcv+0x7af/0x1c40 net/ipv6/icmp.c:927
 ip6_protocol_deliver_rcu+0x3aa/0x1940 net/ipv6/ip6_input.c:394
 ip6_input_finish+0x84/0x170 net/ipv6/ip6_input.c:434
 NF_HOOK include/linux/netfilter.h:289 [inline]
 NF_HOOK include/linux/netfilter.h:283 [inline]
 ip6_input+0xf9/0x600 net/ipv6/ip6_input.c:443
 dst_input include/net/dst.h:450 [inline]
 ip6_rcv_finish+0x177/0x330 net/ipv6/ip6_input.c:76
 NF_HOOK include/linux/netfilter.h:289 [inline]
 NF_HOOK include/linux/netfilter.h:283 [inline]
 ipv6_rcv+0x113/0x650 net/ipv6/ip6_input.c:272
 __netif_receive_skb_one_core+0x160/0x210 net/core/dev.c:4973
 __netif_receive_skb+0x2c/0x1c0 net/core/dev.c:5083
 process_backlog+0x206/0x750 net/core/dev.c:5923
 napi_poll net/core/dev.c:6346 [inline]
 net_rx_action+0x76d/0x1930 net/core/dev.c:6412
 __do_softirq+0x30b/0xb11 kernel/softirq.c:292

The buggy address belongs to the object at ffff88808c3db340
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 128 bytes inside of
 2048-byte region [ffff88808c3db340, ffff88808c3dbb40)
The buggy address belongs to the page:
page:ffffea000230f680 count:1 mapcount:0 mapping:ffff88812c3f0c40 index:0xffff88808c3daac0 compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea000255ac08 ffffea0001366f88 ffff88812c3f0c40
raw: ffff88808c3daac0 ffff88808c3da240 0000000100000002 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88808c3db280: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff88808c3db300: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
>ffff88808c3db380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff88808c3db400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88808c3db480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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