==================================================================
BUG: KASAN: use-after-free in ccid_hc_tx_delete+0xe0/0x100 net/dccp/ccid.c:188
Read of size 8 at addr ffff8881cccaa240 by task syz-executor089/6497

CPU: 0 PID: 6497 Comm: syz-executor089 Not tainted 4.20.0-rc6+ #153
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+0x244/0x39d lib/dump_stack.c:113
 print_address_description.cold.7+0x9/0x1ff mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.8+0x242/0x309 mm/kasan/report.c:412
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 ccid_hc_tx_delete+0xe0/0x100 net/dccp/ccid.c:188
 dccp_sk_destruct+0x3c/0x80 net/dccp/proto.c:181
 __sk_destruct+0x107/0xa80 net/core/sock.c:1561
 __rcu_reclaim kernel/rcu/rcu.h:240 [inline]
 rcu_do_batch kernel/rcu/tree.c:2437 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2716 [inline]
 rcu_process_callbacks+0x100a/0x1ac0 kernel/rcu/tree.c:2697
 __do_softirq+0x308/0xb7e kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x17f/0x1c0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0x1cb/0x760 arch/x86/kernel/apic/apic.c:1061
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807
 </IRQ>
RIP: 0010:flex_array_get_ptr+0x44/0x60 lib/flex_array.c:353
Code: fd ff ff 48 85 c0 74 2f 48 89 c3 e8 16 53 f0 fd 48 89 da 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 75 14 48 8b 1b <e8> f7 52 f0 fd 48 89 d8 5b 41 5c 5d c3 31 db eb ef 48 89 df e8 33
RSP: 0018:ffff8881b22ef888 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: dffffc0000000000 RBX: ffff8881c45beeb0 RCX: 0000000000000008
RDX: 1ffff110388bdda3 RSI: ffffffff838f315a RDI: ffff8881c45e2708
RBP: ffff8881b22ef898 R08: ffff8881ae5dc340 R09: fffffbfff163af42
R10: fffffbfff163af42 R11: ffffffff8b1d7a13 R12: 0000000000001093
R13: 000000000000003c R14: ffff8881b22efa30 R15: ffff8881b22ef9b0
 avtab_search_node+0x1f2/0x550 security/selinux/ss/avtab.c:229
 security_compute_sid+0x183f/0x1f40 security/selinux/ss/services.c:1745
 security_transition_sid+0x7d/0xa0 security/selinux/ss/services.c:1821
 socket_sockcreate_sid security/selinux/hooks.c:4527 [inline]
 selinux_socket_post_create+0x598/0x990 security/selinux/hooks.c:4580
 security_socket_post_create+0x6c/0xd0 security/security.c:1389
 __sock_create+0x744/0x930 net/socket.c:1293
 sock_create net/socket.c:1317 [inline]
 __sys_socket+0x106/0x260 net/socket.c:1347
 __do_sys_socket net/socket.c:1356 [inline]
 __se_sys_socket net/socket.c:1354 [inline]
 __x64_sys_socket+0x73/0xb0 net/socket.c:1354
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4466f9
Code: e8 0c e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 7b 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fd2b6896da8 EFLAGS: 00000293 ORIG_RAX: 0000000000000029
RAX: ffffffffffffffda RBX: 00000000006dbc58 RCX: 00000000004466f9
RDX: 0000000000000000 RSI: 0000000000000006 RDI: 000000000000000a
RBP: 00000000006dbc50 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 00000000006dbc5c
R13: 616e732f7665642f R14: 0100000000000000 R15: 00000000006dbd4c

Allocated by task 6478:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490
 kmem_cache_alloc+0x12e/0x730 mm/slab.c:3554
 ccid_new+0x25b/0x3e0 net/dccp/ccid.c:151
 dccp_hdlr_ccid+0x27/0x150 net/dccp/feat.c:44
 __dccp_feat_activate+0x188/0x280 net/dccp/feat.c:344
 dccp_feat_activate_values+0x3c1/0x80a net/dccp/feat.c:1538
 dccp_rcv_request_sent_state_process net/dccp/input.c:472 [inline]
 dccp_rcv_state_process+0x1320/0x1b7e net/dccp/input.c:680
 dccp_v6_do_rcv+0x271/0xbf0 net/dccp/ipv6.c:638
 sk_backlog_rcv include/net/sock.h:932 [inline]
 __release_sock+0x12f/0x3a0 net/core/sock.c:2276
 release_sock+0xad/0x2c0 net/core/sock.c:2789
 inet_wait_for_connect net/ipv4/af_inet.c:588 [inline]
 __inet_stream_connect+0x641/0x1150 net/ipv4/af_inet.c:680
 inet_stream_connect+0x58/0xa0 net/ipv4/af_inet.c:719
 __sys_connect+0x37d/0x4c0 net/socket.c:1664
 __do_sys_connect net/socket.c:1675 [inline]
 __se_sys_connect net/socket.c:1672 [inline]
 __x64_sys_connect+0x73/0xb0 net/socket.c:1672
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 6501:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
 __cache_free mm/slab.c:3498 [inline]
 kmem_cache_free+0x83/0x290 mm/slab.c:3760
 ccid_hc_tx_delete+0xc3/0x100 net/dccp/ccid.c:190
 dccp_hdlr_ccid+0x7d/0x150 net/dccp/feat.c:53
 __dccp_feat_activate+0x188/0x280 net/dccp/feat.c:344
 dccp_feat_activate_values+0x3c1/0x80a net/dccp/feat.c:1538
 dccp_create_openreq_child+0x47a/0x630 net/dccp/minisocks.c:127
 dccp_v6_request_recv_sock+0x278/0x2020 net/dccp/ipv6.c:466
 dccp_check_req+0x47d/0x6d0 net/dccp/minisocks.c:196
 dccp_v6_rcv+0x874/0x1ce9 net/dccp/ipv6.c:744
 ip6_input_finish+0x3fc/0x1aa0 net/ipv6/ip6_input.c:384
 NF_HOOK include/linux/netfilter.h:289 [inline]
 ip6_input+0xe9/0x600 net/ipv6/ip6_input.c:427
 dst_input include/net/dst.h:450 [inline]
 ip6_rcv_finish+0x17a/0x330 net/ipv6/ip6_input.c:76
 NF_HOOK include/linux/netfilter.h:289 [inline]
 ipv6_rcv+0x115/0x640 net/ipv6/ip6_input.c:272
 __netif_receive_skb_one_core+0x14d/0x200 net/core/dev.c:4946
 __netif_receive_skb+0x2c/0x1e0 net/core/dev.c:5056
 process_backlog+0x24e/0x7a0 net/core/dev.c:5864
 napi_poll net/core/dev.c:6287 [inline]
 net_rx_action+0x7fa/0x19b0 net/core/dev.c:6353
 __do_softirq+0x308/0xb7e kernel/softirq.c:292

The buggy address belongs to the object at ffff8881cccaa240
 which belongs to the cache ccid2_hc_tx_sock of size 1240
The buggy address is located 0 bytes inside of
 1240-byte region [ffff8881cccaa240, ffff8881cccaa718)
The buggy address belongs to the page:
page:ffffea0007332a80 count:1 mapcount:0 mapping:ffff8881c5950cc0 index:0x0 compound_mapcount: 0
flags: 0x2fffc0000010200(slab|head)
raw: 02fffc0000010200 ffffea000735ea08 ffffea000733d688 ffff8881c5950cc0
raw: 0000000000000000 ffff8881cccaa240 0000000100000005 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881cccaa100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881cccaa180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8881cccaa200: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
                                           ^
 ffff8881cccaa280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881cccaa300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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