==================================================================
BUG: KASAN: use-after-free in ccid_hc_tx_delete+0xde/0x100 net/dccp/ccid.c:188
Read of size 8 at addr ffff8880a0622940 by task syz-executor.3/31023

CPU: 0 PID: 31023 Comm: syz-executor.3 Not tainted 5.1.0-rc3+ #50
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:do_user_addr_fault arch/x86/mm/fault.c:1326 [inline]
RIP: 0010:__do_page_fault+0x78f/0xda0 arch/x86/mm/fault.c:1541
Code: ff df 48 c1 e8 03 80 3c 10 00 0f 85 55 05 00 00 48 83 3d 33 12 61 07 00 0f 84 eb 04 00 00 e8 68 0a 3f 00 fb 66 0f 1f 44 00 00 <c7> 45 c0 14 00 00 00 e9 01 fb ff ff e8 50 0a 3f 00 4c 89 e6 4c 89
RSP: 0018:ffff8881534479a0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000040000 RBX: 00000000200d8000 RCX: ffffc9000c42a000
RDX: 0000000000040000 RSI: ffffffff81318498 RDI: ffff88808c3d0f3c
RBP: ffff888153447a10 R08: ffff88808c3d06c0 R09: ffff88808c3d0f60
R10: 0000000000000000 R11: 0000000000000000 R12: 00000000200d8000
R13: 0000000000000000 R14: ffff888153447a58 R15: ffff888153447ae0
 do_page_fault+0x71/0x581 arch/x86/mm/fault.c:1572
 page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1143
RIP: 0010:copy_user_enhanced_fast_string+0xe/0x20 arch/x86/lib/copy_user_64.S:181
Code: 89 d1 c1 e9 03 83 e2 07 f3 48 a5 89 d1 f3 a4 31 c0 0f 1f 00 c3 0f 1f 80 00 00 00 00 0f 1f 00 83 fa 40 0f 82 70 ff ff ff 89 d1 <f3> a4 31 c0 0f 1f 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 83
RSP: 0018:ffff888153447b00 EFLAGS: 00010206
RAX: 0000000000000000 RBX: 0000000000001000 RCX: 0000000000000340
RDX: 0000000000001000 RSI: 00000000200d8000 RDI: ffff888151cf7cc0
RBP: ffff888153447b38 R08: ffffed102a39f000 R09: 0000000000000000
R10: ffffed102a39efff R11: ffff888151cf7fff R12: 00000000200d7340
R13: ffff888151cf7000 R14: 00000000200d8340 R15: 00007ffffffff000
 copy_page_from_iter_iovec lib/iov_iter.c:294 [inline]
 copy_page_from_iter+0x3ad/0x7d0 lib/iov_iter.c:920
 pipe_write+0x281/0xf30 fs/pipe.c:454
 call_write_iter include/linux/fs.h:1863 [inline]
 new_sync_write+0x4c7/0x760 fs/read_write.c:474
 __vfs_write+0xe4/0x110 fs/read_write.c:487
 vfs_write+0x20c/0x580 fs/read_write.c:549
 ksys_write+0xea/0x1f0 fs/read_write.c:598
 __do_sys_write fs/read_write.c:610 [inline]
 __se_sys_write fs/read_write.c:607 [inline]
 __ia32_sys_write+0x71/0xb0 fs/read_write.c:607
 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline]
 do_fast_syscall_32+0x281/0xc98 arch/x86/entry/common.c:397
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139
RIP: 0023:0xf7f9b869
Code: 85 d2 74 02 89 0a 5b 5d c3 8b 04 24 c3 8b 14 24 c3 8b 3c 24 c3 90 90 90 90 90 90 90 90 90 90 90 90 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 002b:00000000f5d970cc EFLAGS: 00000296 ORIG_RAX: 0000000000000004
RAX: ffffffffffffffda RBX: 0000000000000009 RCX: 0000000020000340
RDX: 0000000041395527 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 31038:
 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:437 [inline]
 slab_alloc mm/slab.c:3394 [inline]
 kmem_cache_alloc+0x11a/0x6f0 mm/slab.c:3556
 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:943 [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:1808
 __do_sys_connect net/socket.c:1819 [inline]
 __se_sys_connect net/socket.c:1816 [inline]
 __ia32_sys_connect+0x72/0xb0 net/socket.c:1816
 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline]
 do_fast_syscall_32+0x281/0xc98 arch/x86/entry/common.c:397
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139

Freed by task 31044:
 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:3500 [inline]
 kmem_cache_free+0x86/0x260 mm/slab.c:3766
 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+0x214/0x1e80 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 ffff8880a0622940
 which belongs to the cache ccid2_hc_tx_sock of size 1240
The buggy address is located 0 bytes inside of
 1240-byte region [ffff8880a0622940, ffff8880a0622e18)
The buggy address belongs to the page:
page:ffffea0002818880 count:1 mapcount:0 mapping:ffff88809b3b6840 index:0x0 compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea00023ff288 ffffea0001389388 ffff88809b3b6840
raw: 0000000000000000 ffff8880a06223c0 0000000100000005 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a0622800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a0622880: fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880a0622900: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
                                           ^
 ffff8880a0622980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a0622a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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