==================================================================
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 ffff8800b09f4f30 by task syz-executor2/7414

CPU: 0 PID: 7414 Comm: syz-executor2 Not tainted 4.4.157+ #37
 0000000000000000 5c88fb259a280f53 ffff8800b9257838 ffffffff81a559fd
 ffffea0002c27d00 ffff8800b09f4f30 0000000000000000 ffff8800b09f4f30
 dffffc0000000000 ffff8800b9257870 ffffffff8146c697 ffff8800b09f4f30
Call Trace:
 [<ffffffff81a559fd>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81a559fd>] dump_stack+0xc1/0x124 lib/dump_stack.c:51
 [<ffffffff8146c697>] print_address_description+0x6c/0x217 mm/kasan/report.c:252
 [<ffffffff8146c9b7>] kasan_report_error mm/kasan/report.c:351 [inline]
 [<ffffffff8146c9b7>] kasan_report.cold.6+0x175/0x2f7 mm/kasan/report.c:408
 [<ffffffff81461884>] __asan_report_load2_noabort+0x14/0x20 mm/kasan/report.c:427
 [<ffffffff823b4242>] tcp_skb_pcount include/net/tcp.h:798 [inline]
 [<ffffffff823b4242>] tcp_init_tso_segs net/ipv4/tcp_output.c:1631 [inline]
 [<ffffffff823b4242>] tcp_write_xmit+0x3b22/0x4680 net/ipv4/tcp_output.c:2068
 [<ffffffff823b5504>] __tcp_push_pending_frames+0xa4/0x2a0 net/ipv4/tcp_output.c:2319
 [<ffffffff823bc4a6>] tcp_send_fin+0x176/0xab0 net/ipv4/tcp_output.c:2895
 [<ffffffff8237bd17>] tcp_close+0xc97/0xf60 net/ipv4/tcp.c:2112
 [<ffffffff8242438f>] inet_release+0xff/0x1d0 net/ipv4/af_inet.c:435
 [<ffffffff821566c9>] __sock_release+0xd9/0x260 net/socket.c:592
 [<ffffffff82156869>] sock_close+0x19/0x20 net/socket.c:1050
 [<ffffffff81478bc5>] __fput+0x235/0x6f0 fs/file_table.c:208
 [<ffffffff81479105>] ____fput+0x15/0x20 fs/file_table.c:244
 [<ffffffff8112a85f>] task_work_run+0x10f/0x190 kernel/task_work.c:115
 [<ffffffff810fe372>] get_signal+0x1182/0x14a0 kernel/signal.c:2151
 [<ffffffff8100bc65>] do_signal+0x95/0x1840 arch/x86/kernel/signal.c:712
 [<ffffffff81003eba>] exit_to_usermode_loop+0x11a/0x160 arch/x86/entry/common.c:249
 [<ffffffff810062f8>] prepare_exit_to_usermode arch/x86/entry/common.c:284 [inline]
 [<ffffffff810062f8>] syscall_return_slowpath arch/x86/entry/common.c:349 [inline]
 [<ffffffff810062f8>] do_syscall_32_irqs_on arch/x86/entry/common.c:399 [inline]
 [<ffffffff810062f8>] do_fast_syscall_32+0x618/0x8b0 arch/x86/entry/common.c:460
 [<ffffffff826926d0>] sysenter_flags_fixed+0xd/0x1a

Allocated by task 7405:
 [<ffffffff8102dd46>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff81460902>] save_stack mm/kasan/kasan.c:512 [inline]
 [<ffffffff81460902>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff81460902>] kasan_kmalloc.part.1+0x62/0xf0 mm/kasan/kasan.c:616
 [<ffffffff81460b7f>] kasan_kmalloc+0xaf/0xc0 mm/kasan/kasan.c:601
 [<ffffffff81461142>] kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:554
 [<ffffffff8145c9ac>] slab_post_alloc_hook mm/slub.c:1349 [inline]
 [<ffffffff8145c9ac>] slab_alloc_node mm/slub.c:2615 [inline]
 [<ffffffff8145c9ac>] slab_alloc mm/slub.c:2623 [inline]
 [<ffffffff8145c9ac>] kmem_cache_alloc+0xdc/0x2c0 mm/slub.c:2628
 [<ffffffff8217a4c6>] kmem_cache_alloc_node include/linux/slab.h:350 [inline]
 [<ffffffff8217a4c6>] __alloc_skb+0xe6/0x5b0 net/core/skbuff.c:218
 [<ffffffff82376343>] alloc_skb_fclone include/linux/skbuff.h:856 [inline]
 [<ffffffff82376343>] sk_stream_alloc_skb+0xa3/0x5d0 net/ipv4/tcp.c:833
 [<ffffffff82378fd1>] tcp_sendmsg+0xf81/0x2b30 net/ipv4/tcp.c:1178
 [<ffffffff82426413>] inet_sendmsg+0x203/0x4d0 net/ipv4/af_inet.c:755
 [<ffffffff8215b17b>] sock_sendmsg_nosec net/socket.c:638 [inline]
 [<ffffffff8215b17b>] sock_sendmsg+0xbb/0x110 net/socket.c:648
 [<ffffffff8215f380>] SYSC_sendto net/socket.c:1678 [inline]
 [<ffffffff8215f380>] SyS_sendto+0x220/0x370 net/socket.c:1646
 [<ffffffff81005ffe>] do_syscall_32_irqs_on arch/x86/entry/common.c:393 [inline]
 [<ffffffff81005ffe>] do_fast_syscall_32+0x31e/0x8b0 arch/x86/entry/common.c:460
 [<ffffffff826926d0>] sysenter_flags_fixed+0xd/0x1a

Freed by task 7414:
 [<ffffffff8102dd46>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff814611fc>] save_stack mm/kasan/kasan.c:512 [inline]
 [<ffffffff814611fc>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff814611fc>] kasan_slab_free+0xac/0x190 mm/kasan/kasan.c:589
 [<ffffffff8145e01e>] slab_free_hook mm/slub.c:1383 [inline]
 [<ffffffff8145e01e>] slab_free_freelist_hook mm/slub.c:1405 [inline]
 [<ffffffff8145e01e>] slab_free mm/slub.c:2859 [inline]
 [<ffffffff8145e01e>] kmem_cache_free+0xbe/0x340 mm/slub.c:2881
 [<ffffffff8217298f>] kfree_skbmem+0xcf/0x100 net/core/skbuff.c:635
 [<ffffffff8217fd2d>] __kfree_skb+0x1d/0x20 net/core/skbuff.c:676
 [<ffffffff823b62c9>] sk_wmem_free_skb include/net/sock.h:1447 [inline]
 [<ffffffff823b62c9>] tcp_write_queue_purge include/net/tcp.h:1460 [inline]
 [<ffffffff823b62c9>] tcp_connect_init net/ipv4/tcp_output.c:3134 [inline]
 [<ffffffff823b62c9>] tcp_connect+0xae9/0x3110 net/ipv4/tcp_output.c:3273
 [<ffffffff823c41d1>] tcp_v4_connect+0xf31/0x1890 net/ipv4/tcp_ipv4.c:246
 [<ffffffff82425329>] __inet_stream_connect+0x2a9/0xc30 net/ipv4/af_inet.c:615
 [<ffffffff82425d05>] inet_stream_connect+0x55/0xa0 net/ipv4/af_inet.c:676
 [<ffffffff8215eae8>] SYSC_connect net/socket.c:1570 [inline]
 [<ffffffff8215eae8>] SyS_connect+0x1b8/0x310 net/socket.c:1551
 [<ffffffff81005ffe>] do_syscall_32_irqs_on arch/x86/entry/common.c:393 [inline]
 [<ffffffff81005ffe>] do_fast_syscall_32+0x31e/0x8b0 arch/x86/entry/common.c:460
 [<ffffffff826926d0>] sysenter_flags_fixed+0xd/0x1a

The buggy address belongs to the object at ffff8800b09f4f00
 which belongs to the cache skbuff_fclone_cache of size 456
The buggy address is located 48 bytes inside of
 456-byte region [ffff8800b09f4f00, ffff8800b09f50c8)
The buggy address belongs to the page:
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory accessgeneral protection fault: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 1 PID: 2147 Comm: syz-executor1 Not tainted 4.4.157+ #37
task: ffff8801d2d2af80 task.stack: ffff8801d2c98000
RIP: 0010:[<ffffffff81a72648>]  [<ffffffff81a72648>] timerqueue_add+0xb8/0x2b0 lib/timerqueue.c:51
RSP: 0018:ffff8801d2c9fa68  EFLAGS: 00010006
RAX: ffffed003a593fa8 RBX: ffff8801d2c9fd28 RCX: ffffed003a5a5708
RDX: 00001083e1e5ccc3 RSI: ffffffff81a7262c RDI: 0000841f0f2e6618
RBP: ffff8801d2c9faa8 R08: ffff8801d2d2b848 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000001 R12: dffffc0000000000
R13: 0000841f0f2e6600 R14: 00000032e592c4bd R15: ffffffff8140a835
FS:  0000000000000000(0000) GS:ffff8801db700000(0063) knlGS:000000000a0cf900
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00000000f771affc CR3: 00000001d3bf6000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801d2c9fd40 ffff8801db719390 ffffed003a593fa8 ffff8801db719380
 ffff8801d2c9fd28 ffff8801db7192c0 0000000000000001 0000000000000000
 ffff8801d2c9fae0 ffffffff81252cef 0000000000000863 ffff8801db719380
Call Trace:
 [<ffffffff81252cef>] enqueue_hrtimer+0x15f/0x440 kernel/time/hrtimer.c:893
 [<ffffffff81255263>] hrtimer_start_range_ns+0x573/0x1410 kernel/time/hrtimer.c:1013
 [<ffffffff8268eab6>] hrtimer_start_expires include/linux/hrtimer.h:407 [inline]
 [<ffffffff8268eab6>] do_nanosleep+0x196/0x4f0 kernel/time/hrtimer.c:1500
 [<ffffffff81257d50>] hrtimer_nanosleep+0x210/0x550 kernel/time/hrtimer.c:1572
 [<ffffffff812a4aa9>] C_SYSC_nanosleep kernel/compat.c:254 [inline]
 [<ffffffff812a4aa9>] compat_SyS_nanosleep+0x289/0x390 kernel/compat.c:239
 [<ffffffff81005ffe>] do_syscall_32_irqs_on arch/x86/entry/common.c:393 [inline]
 [<ffffffff81005ffe>] do_fast_syscall_32+0x31e/0x8b0 arch/x86/entry/common.c:460
 [<ffffffff826926d0>] sysenter_flags_fixed+0xd/0x1a
Code: 00 00 4d 8b 2f 4d 85 ed 74 3d e8 54 27 88 ff 48 8b 45 d0 80 38 00 0f 85 96 01 00 00 49 8d 7d 18 4c 8b 73 18 48 89 fa 48 c1 ea 03 <42> 80 3c 22 00 0f 85 8a 01 00 00 4d 3b 75 18 7c a3 e8 22 27 88 
RIP  [<ffffffff81a72648>] timerqueue_add+0xb8/0x2b0 lib/timerqueue.c:51
 RSP <ffff8801d2c9fa68>
---[ end trace 04040c2bc9f108e1 ]---