==================================================================
BUG: KASAN: use-after-free in tcp_skb_pcount include/net/tcp.h:798 [inline]
BUG: KASAN: use-after-free in tcp_init_tso_segs net/ipv4/tcp_output.c:1631 [inline]
BUG: KASAN: use-after-free in tcp_write_xmit+0x3b22/0x4680 net/ipv4/tcp_output.c:2068
Read of size 2 at addr ffff8801d2e207b0 by task syz-executor0/7450

CPU: 1 PID: 7450 Comm: syz-executor0 Not tainted 4.4.163+ #122
 0000000000000000 2c1e93f1d3351ac6 ffff8800ba2cf880 ffffffff81aa556d
 ffffea00074b8800 ffff8801d2e207b0 0000000000000000 ffff8801d2e207b0
 dffffc0000000000 ffff8800ba2cf8b8 ffffffff8148a8db ffff8801d2e207b0
Call Trace:
 [<ffffffff81aa556d>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81aa556d>] dump_stack+0xc1/0x124 lib/dump_stack.c:51
 [<ffffffff8148a8db>] print_address_description+0x6c/0x217 mm/kasan/report.c:252
 [<ffffffff8148abfb>] kasan_report_error mm/kasan/report.c:351 [inline]
 [<ffffffff8148abfb>] kasan_report.cold.6+0x175/0x2f7 mm/kasan/report.c:408
 [<ffffffff8147f8e4>] __asan_report_load2_noabort+0x14/0x20 mm/kasan/report.c:427
 [<ffffffff82430342>] tcp_skb_pcount include/net/tcp.h:798 [inline]
 [<ffffffff82430342>] tcp_init_tso_segs net/ipv4/tcp_output.c:1631 [inline]
 [<ffffffff82430342>] tcp_write_xmit+0x3b22/0x4680 net/ipv4/tcp_output.c:2068
 [<ffffffff82431734>] __tcp_push_pending_frames+0xa4/0x2a0 net/ipv4/tcp_output.c:2319
 [<ffffffff824386d6>] tcp_send_fin+0x176/0xab0 net/ipv4/tcp_output.c:2895
 [<ffffffff823f8357>] tcp_close+0xc97/0xf60 net/ipv4/tcp.c:2112
 [<ffffffff824a073f>] inet_release+0xff/0x1d0 net/ipv4/af_inet.c:435
 [<ffffffff821cadd9>] __sock_release+0xd9/0x260 net/socket.c:592
 [<ffffffff821caf79>] sock_close+0x19/0x20 net/socket.c:1050
 [<ffffffff81496e35>] __fput+0x235/0x6f0 fs/file_table.c:208
 [<ffffffff81497375>] ____fput+0x15/0x20 fs/file_table.c:244
 [<ffffffff8112f23f>] task_work_run+0x10f/0x190 kernel/task_work.c:115
 [<ffffffff81101ab2>] get_signal+0x1182/0x14a0 kernel/signal.c:2151
 [<ffffffff8100bf65>] do_signal+0x95/0x1840 arch/x86/kernel/signal.c:712
 [<ffffffff81003eba>] exit_to_usermode_loop+0x11a/0x160 arch/x86/entry/common.c:250
 [<ffffffff81005924>] prepare_exit_to_usermode arch/x86/entry/common.c:287 [inline]
 [<ffffffff81005924>] syscall_return_slowpath+0x254/0x2d0 arch/x86/entry/common.c:352
 [<ffffffff8271256d>] int_ret_from_sys_call+0x25/0xa3

Allocated by task 7436:
 [<ffffffff8102e4d6>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff8147e962>] save_stack mm/kasan/kasan.c:512 [inline]
 [<ffffffff8147e962>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff8147e962>] kasan_kmalloc.part.1+0x62/0xf0 mm/kasan/kasan.c:616
 [<ffffffff8147ebdf>] kasan_kmalloc+0xaf/0xc0 mm/kasan/kasan.c:601
 [<ffffffff8147f1a2>] kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:554
 [<ffffffff8147a89c>] slab_post_alloc_hook mm/slub.c:1349 [inline]
 [<ffffffff8147a89c>] slab_alloc_node mm/slub.c:2615 [inline]
 [<ffffffff8147a89c>] slab_alloc mm/slub.c:2623 [inline]
 [<ffffffff8147a89c>] kmem_cache_alloc+0xdc/0x2c0 mm/slub.c:2628
 [<ffffffff821eef56>] kmem_cache_alloc_node include/linux/slab.h:350 [inline]
 [<ffffffff821eef56>] __alloc_skb+0xe6/0x5b0 net/core/skbuff.c:218
 [<ffffffff823f2983>] alloc_skb_fclone include/linux/skbuff.h:856 [inline]
 [<ffffffff823f2983>] sk_stream_alloc_skb+0xa3/0x5d0 net/ipv4/tcp.c:833
 [<ffffffff823f5611>] tcp_sendmsg+0xf81/0x2b30 net/ipv4/tcp.c:1178
 [<ffffffff824a27c3>] inet_sendmsg+0x203/0x4d0 net/ipv4/af_inet.c:755
 [<ffffffff821cf9eb>] sock_sendmsg_nosec net/socket.c:638 [inline]
 [<ffffffff821cf9eb>] sock_sendmsg+0xbb/0x110 net/socket.c:648
 [<ffffffff821d3c10>] SYSC_sendto net/socket.c:1678 [inline]
 [<ffffffff821d3c10>] SyS_sendto+0x220/0x370 net/socket.c:1646
 [<ffffffff827123e1>] entry_SYSCALL_64_fastpath+0x1e/0x9a

Freed by task 7450:
 [<ffffffff8102e4d6>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff8147f25c>] save_stack mm/kasan/kasan.c:512 [inline]
 [<ffffffff8147f25c>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff8147f25c>] kasan_slab_free+0xac/0x190 mm/kasan/kasan.c:589
 [<ffffffff8147bf5e>] slab_free_hook mm/slub.c:1383 [inline]
 [<ffffffff8147bf5e>] slab_free_freelist_hook mm/slub.c:1405 [inline]
 [<ffffffff8147bf5e>] slab_free mm/slub.c:2859 [inline]
 [<ffffffff8147bf5e>] kmem_cache_free+0xbe/0x350 mm/slub.c:2881
 [<ffffffff821e741f>] kfree_skbmem+0xcf/0x100 net/core/skbuff.c:635
 [<ffffffff821f47bd>] __kfree_skb+0x1d/0x20 net/core/skbuff.c:676
 [<ffffffff824324f9>] sk_wmem_free_skb include/net/sock.h:1447 [inline]
 [<ffffffff824324f9>] tcp_write_queue_purge include/net/tcp.h:1460 [inline]
 [<ffffffff824324f9>] tcp_connect_init net/ipv4/tcp_output.c:3134 [inline]
 [<ffffffff824324f9>] tcp_connect+0xae9/0x3110 net/ipv4/tcp_output.c:3273
 [<ffffffff82440401>] tcp_v4_connect+0xf31/0x1890 net/ipv4/tcp_ipv4.c:246
 [<ffffffff824a16d9>] __inet_stream_connect+0x2a9/0xc30 net/ipv4/af_inet.c:615
 [<ffffffff823f6097>] tcp_sendmsg_fastopen net/ipv4/tcp.c:1092 [inline]
 [<ffffffff823f6097>] tcp_sendmsg+0x1a07/0x2b30 net/ipv4/tcp.c:1112
 [<ffffffff824a27c3>] inet_sendmsg+0x203/0x4d0 net/ipv4/af_inet.c:755
 [<ffffffff821cf9eb>] sock_sendmsg_nosec net/socket.c:638 [inline]
 [<ffffffff821cf9eb>] sock_sendmsg+0xbb/0x110 net/socket.c:648
 [<ffffffff821d3c10>] SYSC_sendto net/socket.c:1678 [inline]
 [<ffffffff821d3c10>] SyS_sendto+0x220/0x370 net/socket.c:1646
 [<ffffffff827123e1>] entry_SYSCALL_64_fastpath+0x1e/0x9a

The buggy address belongs to the object at ffff8801d2e20780
 which belongs to the cache skbuff_fclone_cache of size 456
The buggy address is located 48 bytes inside of
 456-byte region [ffff8801d2e20780, ffff8801d2e20948)
The buggy address belongs to the page:
------------[ cut here ]------------
WARNING: CPU: 0 PID: 7444 at kernel/locking/lockdep.c:973 lock_accessed kernel/locking/lockdep.c:973 [inline]()
WARNING: CPU: 0 PID: 7444 at kernel/locking/lockdep.c:973 __bfs+0x2a9/0x5f0 kernel/locking/lockdep.c:1040()