BUG: KASAN: use-after-free in ccid2_hc_tx_rto_expire+0x51c/0x5c0 net/dccp/ccids/ccid2.c:144
Read of size 4 at addr ffff8801d207aa40 by task syz-executor4/7548

CPU: 0 PID: 7548 Comm: syz-executor4 Not tainted 4.13.0-rc5+ #7
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:16 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:52
 print_address_description+0x73/0x250 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report+0x24e/0x340 mm/kasan/report.c:409
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:429
 ccid2_hc_tx_rto_expire+0x51c/0x5c0 net/dccp/ccids/ccid2.c:144
 call_timer_fn+0x233/0x830 kernel/time/timer.c:1268
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=61952 sclass=netlink_route_socket pig=7589 comm=syz-executor2
 expire_timers kernel/time/timer.c:1307 [inline]
 __run_timers+0x7fd/0xb90 kernel/time/timer.c:1601
 run_timer_softirq+0x21/0x80 kernel/time/timer.c:1614
 __do_softirq+0x2f5/0xba3 kernel/softirq.c:284
 invoke_softirq kernel/softirq.c:364 [inline]
 irq_exit+0x1cc/0x200 kernel/softirq.c:405
 exiting_irq arch/x86/include/asm/apic.h:638 [inline]
 smp_apic_timer_interrupt+0x76/0xa0 arch/x86/kernel/apic/apic.c:1044
 apic_timer_interrupt+0x93/0xa0 arch/x86/entry/entry_64.S:702
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:814 [inline]
RIP: 0010:lock_acquire+0x256/0x580 kernel/locking/lockdep.c:3858
RSP: 0018:ffff8801caef6fe8 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff10
RAX: dffffc0000000000 RBX: ffff8801c77fc100 RCX: 0000000000000000
RDX: 1ffffffff0b595f9 RSI: 000000009b292d67 RDI: 0000000000000286
RBP: ffff8801caef70e0 R08: 0000000000000001 R09: 0000000000000005
R10: ffff8801caef6fc8 R11: ffffffff8194fb90 R12: 1ffff100395dee03
R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000001
 </IRQ>
 __might_fault+0x13a/0x1d0 mm/memory.c:4317
 _copy_from_user+0x2c/0x110 lib/usercopy.c:9
 copy_from_user include/linux/uaccess.h:146 [inline]
 sctp_getsockopt_primary_addr+0xa0/0x310 net/sctp/socket.c:5545
 sctp_getsockopt+0x1bc4/0x6dc0 net/sctp/socket.c:6852
 sock_common_getsockopt+0x95/0xd0 net/core/sock.c:2932
 SYSC_getsockopt net/socket.c:1883 [inline]
 SyS_getsockopt+0x178/0x340 net/socket.c:1865
 entry_SYSCALL_64_fastpath+0x1f/0xbe
RIP: 0033:0x4512e9
RSP: 002b:00007f7b775a2c08 EFLAGS: 00000216 ORIG_RAX: 0000000000000037
RAX: ffffffffffffffda RBX: 0000000000718000 RCX: 00000000004512e9
RDX: 0000000000000006 RSI: 0000000000000084 RDI: 0000000000000016
RBP: 0000000000000086 R08: 0000000020dca000 R09: 0000000000000000
R10: 0000000020817f74 R11: 0000000000000216 R12: 0000000000000000
R13: 0000000000a6f7ef R14: 00007f7b775a39c0 R15: 0000000000000000

Allocated by task 7488:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489
 kmem_cache_alloc+0x127/0x750 mm/slab.c:3561
 ccid_new+0x20e/0x390 net/dccp/ccid.c:151
 dccp_hdlr_ccid+0x27/0x140 net/dccp/feat.c:44
 __dccp_feat_activate+0x142/0x2a0 net/dccp/feat.c:344
 dccp_feat_activate_values+0x34e/0xa90 net/dccp/feat.c:1538
 dccp_rcv_request_sent_state_process net/dccp/input.c:472 [inline]
 dccp_rcv_state_process+0xed1/0x1620 net/dccp/input.c:677
 dccp_v4_do_rcv+0xeb/0x160 net/dccp/ipv4.c:679
 sk_backlog_rcv include/net/sock.h:911 [inline]
 __release_sock+0x124/0x360 net/core/sock.c:2269
 release_sock+0xa4/0x2a0 net/core/sock.c:2784
 inet_wait_for_connect net/ipv4/af_inet.c:557 [inline]
 __inet_stream_connect+0x671/0xf00 net/ipv4/af_inet.c:643
 inet_stream_connect+0x58/0xa0 net/ipv4/af_inet.c:682
 SYSC_connect+0x204/0x470 net/socket.c:1642
 SyS_connect+0x24/0x30 net/socket.c:1623
 entry_SYSCALL_64_fastpath+0x1f/0xbe

Freed by task 7515:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3503 [inline]
 kmem_cache_free+0x77/0x280 mm/slab.c:3763
 ccid_hc_tx_delete+0xc5/0x100 net/dccp/ccid.c:190
 dccp_destroy_sock+0x2fb/0x460 net/dccp/proto.c:222
 inet_csk_destroy_sock+0x166/0x3f0 net/ipv4/inet_connection_sock.c:833
 dccp_done+0xb7/0xd0 net/dccp/proto.c:145
 dccp_time_wait+0x13d/0x300 net/dccp/minisocks.c:72
 dccp_rcv_reset+0x1d1/0x5b0 net/dccp/input.c:160
 dccp_rcv_state_process+0x8fc/0x1620 net/dccp/input.c:663
 dccp_v4_do_rcv+0xeb/0x160 net/dccp/ipv4.c:679
 sk_backlog_rcv include/net/sock.h:911 [inline]
 __sk_receive_skb+0x33e/0xc00 net/core/sock.c:521
 dccp_v4_rcv+0xef1/0x1c00 net/dccp/ipv4.c:871
 ip_local_deliver_finish+0x2e2/0xba0 net/ipv4/ip_input.c:216
 NF_HOOK include/linux/netfilter.h:248 [inline]
 ip_local_deliver+0x1ce/0x6d0 net/ipv4/ip_input.c:257
 dst_input include/net/dst.h:477 [inline]
 ip_rcv_finish+0x8db/0x19c0 net/ipv4/ip_input.c:397
 NF_HOOK include/linux/netfilter.h:248 [inline]
 ip_rcv+0xc3f/0x17d0 net/ipv4/ip_input.c:488
 __netif_receive_skb_core+0x19af/0x33d0 net/core/dev.c:4418
 __netif_receive_skb+0x2c/0x1b0 net/core/dev.c:4456
 process_backlog+0x203/0x740 net/core/dev.c:5132
 napi_poll net/core/dev.c:5529 [inline]
 net_rx_action+0x792/0x1910 net/core/dev.c:5595
 __do_softirq+0x2f5/0xba3 kernel/softirq.c:284

The buggy address belongs to the object at ffff8801d207a600
 which belongs to the cache ccid2_hc_tx_sock of size 1240
The buggy address is located 1088 bytes inside of
 1240-byte region [ffff8801d207a600, ffff8801d207aad8)
The buggy address belongs to the page:
page:ffffea0007481e80 count:1 mapcount:0 mapping:ffff8801d207a080 index:0x0 compound_mapcount: 0
flags: 0x200000000008100(slab|head)
raw: 0200000000008100 ffff8801d207a080 0000000000000000 0000000100000005
raw: ffffea0007495320 ffff8801d3a76248 ffff8801d3a79840 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d207a900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801d207a980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801d207aa00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff8801d207aa80: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc
 ffff8801d207ab00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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