==================================================================
BUG: KASAN: use-after-free in ccid_hc_tx_delete+0xde/0x100 net/dccp/ccid.c:188
Read of size 8 at addr ffff8880a1718040 by task syz-executor.5/7806

CPU: 0 PID: 7806 Comm: syz-executor.5 Not tainted 5.1.0-rc2 #36
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.cold+0x7c/0x20d mm/kasan/report.c:187
 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132
 ccid_hc_tx_delete+0xde/0x100 net/dccp/ccid.c:188
 dccp_sk_destruct+0x3f/0x90 net/dccp/proto.c:181
 __sk_destruct+0x55/0x6d0 net/core/sock.c:1699
 __rcu_reclaim kernel/rcu/rcu.h:227 [inline]
 rcu_do_batch kernel/rcu/tree.c:2475 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2788 [inline]
 rcu_core+0x928/0x1390 kernel/rcu/tree.c:2769
 __do_softirq+0x266/0x95a kernel/softirq.c:293
 invoke_softirq kernel/softirq.c:374 [inline]
 irq_exit+0x180/0x1d0 kernel/softirq.c:414
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0x14a/0x570 arch/x86/kernel/apic/apic.c:1062
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807
 </IRQ>
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x54/0x90 kernel/locking/spinlock.c:192
Code: c0 00 97 92 88 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 33 48 83 3d b5 3b 83 01 00 74 20 fb 66 0f 1f 44 00 00 <bf> 01 00 00 00 e8 92 64 3e fa 65 8b 05 2b 92 f2 78 85 c0 74 06 41
RSP: 0018:ffff88805bee7b18 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff11252e0 RBX: ffff88805bed8000 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffff88805bed887c
RBP: ffff88805bee7b20 R08: ffff88805bed8000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880ae82cf80
R13: ffff8880565fe440 R14: 0000000000000000 R15: 0000000000000000
 finish_lock_switch kernel/sched/core.c:2627 [inline]
 finish_task_switch+0x146/0x780 kernel/sched/core.c:2727
 context_switch kernel/sched/core.c:2880 [inline]
 __schedule+0x81f/0x1cc0 kernel/sched/core.c:3518
 schedule+0x92/0x180 kernel/sched/core.c:3562
 freezable_schedule include/linux/freezer.h:172 [inline]
 do_nanosleep+0x201/0x6a0 kernel/time/hrtimer.c:1679
 hrtimer_nanosleep+0x2a6/0x570 kernel/time/hrtimer.c:1733
 __do_sys_nanosleep kernel/time/hrtimer.c:1767 [inline]
 __se_sys_nanosleep kernel/time/hrtimer.c:1754 [inline]
 __x64_sys_nanosleep+0x1a6/0x220 kernel/time/hrtimer.c:1754
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4859d0
Code: 00 00 48 c7 c0 d4 ff ff ff 64 c7 00 16 00 00 00 31 c0 eb be 66 0f 1f 44 00 00 83 3d 81 0d 5d 00 00 75 14 b8 23 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 b4 e0 f8 ff c3 48 83 ec 08 e8 ea 53 fd ff
RSP: 002b:00007fffb462aa68 EFLAGS: 00000246 ORIG_RAX: 0000000000000023
RAX: ffffffffffffffda RBX: 00000000000653d5 RCX: 00000000004859d0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007fffb462aa70
RBP: 0000000000000564 R08: 0000000000000001 R09: 00000000017af940
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 00007fffb462aac0 R14: 000000000006537b R15: 00007fffb462aad0

Allocated by task 15882:
 save_stack+0x45/0xd0 mm/kasan/common.c:75
 set_track mm/kasan/common.c:87 [inline]
 __kasan_kmalloc mm/kasan/common.c:497 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:470
 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:505
 slab_post_alloc_hook mm/slab.h:436 [inline]
 slab_alloc mm/slab.c:3392 [inline]
 kmem_cache_alloc+0x11a/0x6f0 mm/slab.c:3554
 ccid_new+0x256/0x3f0 net/dccp/ccid.c:151
 dccp_hdlr_ccid+0x27/0x150 net/dccp/feat.c:44
 __dccp_feat_activate+0x17a/0x270 net/dccp/feat.c:344
 dccp_feat_activate_values+0x33a/0x766 net/dccp/feat.c:1538
 dccp_rcv_request_sent_state_process net/dccp/input.c:472 [inline]
 dccp_rcv_state_process+0x116f/0x1935 net/dccp/input.c:680
 dccp_v6_do_rcv+0x269/0xbf0 net/dccp/ipv6.c:641
 sk_backlog_rcv include/net/sock.h:937 [inline]
 __release_sock+0x12e/0x3a0 net/core/sock.c:2413
 release_sock+0x59/0x1c0 net/core/sock.c:2929
 inet_wait_for_connect net/ipv4/af_inet.c:588 [inline]
 __inet_stream_connect+0x59f/0xea0 net/ipv4/af_inet.c:680
 inet_stream_connect+0x58/0xa0 net/ipv4/af_inet.c:719
 __sys_connect+0x266/0x330 net/socket.c:1685
 __do_sys_connect net/socket.c:1696 [inline]
 __se_sys_connect net/socket.c:1693 [inline]
 __x64_sys_connect+0x73/0xb0 net/socket.c:1693
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 15887:
 save_stack+0x45/0xd0 mm/kasan/common.c:75
 set_track mm/kasan/common.c:87 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:459
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:467
 __cache_free mm/slab.c:3498 [inline]
 kmem_cache_free+0x86/0x260 mm/slab.c:3764
 ccid_hc_tx_delete+0xc1/0x100 net/dccp/ccid.c:190
 dccp_hdlr_ccid+0x7d/0x150 net/dccp/feat.c:53
 __dccp_feat_activate+0x17a/0x270 net/dccp/feat.c:344
 dccp_feat_activate_values+0x33a/0x766 net/dccp/feat.c:1538
 dccp_create_openreq_child+0x40c/0x570 net/dccp/minisocks.c:127
 dccp_v6_request_recv_sock+0x214/0x1da0 net/dccp/ipv6.c:469
 dccp_check_req+0x35c/0x6f0 net/dccp/minisocks.c:196
 dccp_v6_rcv+0x6d7/0x191e net/dccp/ipv6.c:747
 ip6_protocol_deliver_rcu+0x303/0x16c0 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+0xe4/0x3f0 net/ipv6/ip6_input.c:443
 dst_input include/net/dst.h:450 [inline]
 ip6_rcv_finish+0x1e7/0x320 net/ipv6/ip6_input.c:76
 NF_HOOK include/linux/netfilter.h:289 [inline]
 NF_HOOK include/linux/netfilter.h:283 [inline]
 ipv6_rcv+0x10e/0x420 net/ipv6/ip6_input.c:272
 __netif_receive_skb_one_core+0x115/0x1a0 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+0x4fa/0x1070 net/core/dev.c:6412
 __do_softirq+0x266/0x95a kernel/softirq.c:293

The buggy address belongs to the object at ffff8880a1718040
 which belongs to the cache ccid2_hc_tx_sock of size 1240
The buggy address is located 0 bytes inside of
 1240-byte region [ffff8880a1718040, ffff8880a1718518)
The buggy address belongs to the page:
page:ffffea000285c600 count:1 mapcount:0 mapping:ffff888216b3ee40 index:0x0 compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea00014fd688 ffffea000256ee08 ffff888216b3ee40
raw: 0000000000000000 ffff8880a1718040 0000000100000005 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a1717f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880a1717f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880a1718000: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
                                           ^
 ffff8880a1718080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a1718100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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