==================================================================
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 ffff8800b39a9430 by task syz-executor1/14118

CPU: 0 PID: 14118 Comm: syz-executor1 Not tainted 4.4.163+ #12
 0000000000000000 81cd0f5c325f2ba3 ffff8800a60af7f8 ffffffff81aa556d
 ffffea0002ce6a00 ffff8800b39a9430 0000000000000000 ffff8800b39a9430
 dffffc0000000000 ffff8800a60af830 ffffffff8148a8db ffff8800b39a9430
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
 [<ffffffff823e72b2>] tcp_push+0x3e2/0x5a0 net/ipv4/tcp.c:692
 [<ffffffff823f5d44>] tcp_sendmsg+0x16b4/0x2b30 net/ipv4/tcp.c:1293
 [<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
 [<ffffffff8100629e>] do_syscall_32_irqs_on arch/x86/entry/common.c:396 [inline]
 [<ffffffff8100629e>] do_fast_syscall_32+0x31e/0xa80 arch/x86/entry/common.c:463
 [<ffffffff82713b50>] sysenter_flags_fixed+0xd/0x1a

Allocated by task 14118:
 [<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
 [<ffffffff8100629e>] do_syscall_32_irqs_on arch/x86/entry/common.c:396 [inline]
 [<ffffffff8100629e>] do_fast_syscall_32+0x31e/0xa80 arch/x86/entry/common.c:463
 [<ffffffff82713b50>] sysenter_flags_fixed+0xd/0x1a

Freed by task 14138:
 [<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
 [<ffffffff824a20b5>] inet_stream_connect+0x55/0xa0 net/ipv4/af_inet.c:676
 [<ffffffff821d3378>] SYSC_connect net/socket.c:1570 [inline]
 [<ffffffff821d3378>] SyS_connect+0x1b8/0x310 net/socket.c:1551
 [<ffffffff8100629e>] do_syscall_32_irqs_on arch/x86/entry/common.c:396 [inline]
 [<ffffffff8100629e>] do_fast_syscall_32+0x31e/0xa80 arch/x86/entry/common.c:463
 [<ffffffff82713b50>] sysenter_flags_fixed+0xd/0x1a

The buggy address belongs to the object at ffff8800b39a9400
 which belongs to the cache skbuff_fclone_cache of size 456
The buggy address is located 48 bytes inside of
 456-byte region [ffff8800b39a9400, ffff8800b39a95c8)
The buggy address belongs to the page:
BUG: unable to handle kernel paging request at fffffbfff331af20
IP: [<ffffffff811f0d6c>] cpuacct_charge+0x14c/0x380 kernel/sched/cpuacct.c:247
PGD 21ff68067 PUD 21ff67067 PMD 0 
Oops: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 1 PID: 2122 Comm: syz-executor1 Not tainted 4.4.163+ #12
task: ffff8800b7bedf00 task.stack: ffff8801c3dc8000
RIP: 0010:[<ffffffff811f0d6c>]  [<ffffffff811f0d6c>] cpuacct_charge+0x14c/0x380 kernel/sched/cpuacct.c:247
RSP: 0000:ffff8801c3dcf538  EFLAGS: 00010046
RAX: 1ffffffff05d2a0b RBX: 00000000000181a8 RCX: ffffffff831a2900
RDX: fffffbfff331af20 RSI: ffffffff998d7900 RDI: ffffffff82e95058
RBP: ffff8801c3dcf578 R08: ffff8800b7bee7c8 R09: 01d03681800360cf
R10: ffff8800b7bedf00 R11: 0000000000000001 R12: ffffffff82e94f80
R13: dffffc0000000000 R14: 000000001c4cf4cb R15: 0000000002ce6a00
FS:  0000000000000000(0000) GS:ffff8801db700000(0000) knlGS:0000000000000000
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: fffffbfff331af20 CR3: 0000000002e0a000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff811f0c80 0000000000000046 0000000000000003 ffff8800a72cdf60
 ffff8800a72cdf00 000000001c4cf4cb ffff8800a72cdfb0 0000000000000000
 ffff8801c3dcf5c0 ffffffff8117c469 0000000000056690 0000000041b58ab3
Call Trace:
 [<ffffffff8117c469>] update_curr+0x2c9/0x6d0 kernel/sched/fair.c:882
 [<ffffffff8119c0ba>] enqueue_entity kernel/sched/fair.c:3512 [inline]
 [<ffffffff8119c0ba>] enqueue_task_fair+0x12a/0xab90 kernel/sched/fair.c:4711
 [<ffffffff81163b4d>] enqueue_task kernel/sched/core.c:858 [inline]
 [<ffffffff81163b4d>] activate_task+0x1dd/0x280 kernel/sched/core.c:874
 [<ffffffff81164d2f>] ttwu_activate kernel/sched/core.c:1736 [inline]
 [<ffffffff81164d2f>] ttwu_do_activate.constprop.29+0xbf/0x1e0 kernel/sched/core.c:1789
 [<ffffffff811681cd>] ttwu_queue kernel/sched/core.c:1934 [inline]
 [<ffffffff811681cd>] try_to_wake_up+0x6dd/0x1120 kernel/sched/core.c:2068
 [<ffffffff8116ab70>] wake_up_state+0x10/0x20 kernel/sched/core.c:2148
 [<ffffffff810f8ca4>] signal_wake_up_state+0x44/0x70 kernel/signal.c:659
 [<ffffffff810fa1d5>] signal_wake_up include/linux/sched.h:3332 [inline]
 [<ffffffff810fa1d5>] complete_signal+0x635/0x7b0 kernel/signal.c:942
 [<ffffffff810fa8cf>] __send_signal+0x57f/0x1280 kernel/signal.c:1080
 [<ffffffff810fb61a>] send_signal+0x4a/0xc0 kernel/signal.c:1096
 [<ffffffff810fe244>] do_send_sig_info+0xa4/0x130 kernel/signal.c:1151
 [<ffffffff810fe303>] send_sig_info+0x33/0x50 kernel/signal.c:1436
 [<ffffffff812d87fd>] zap_pid_ns_processes+0x28d/0x690 kernel/pid_namespace.c:223
 [<ffffffff810da739>] find_child_reaper kernel/exit.c:477 [inline]
 [<ffffffff810da739>] forget_original_parent kernel/exit.c:563 [inline]
 [<ffffffff810da739>] exit_notify kernel/exit.c:599 [inline]
 [<ffffffff810da739>] do_exit+0x1d99/0x29a0 kernel/exit.c:776
 [<ffffffff810df5a1>] do_group_exit+0x111/0x300 kernel/exit.c:885
 [<ffffffff81100e1c>] get_signal+0x4ec/0x14a0 kernel/signal.c:2321
 [<ffffffff8100bf65>] do_signal+0x95/0x1840 arch/x86/kernel/signal.c:712
 [<ffffffff81003eba>] exit_to_usermode_loop+0x11a/0x160 arch/x86/entry/common.c:250
 [<ffffffff81005647>] prepare_exit_to_usermode+0x157/0x1e0 arch/x86/entry/common.c:287
 [<ffffffff82712f45>] retint_user+0x8/0x3c
Code: 89 f2 48 c1 ea 03 4c 01 ea 49 8d bc 24 d8 00 00 00 48 89 f8 48 c1 e8 03 42 80 3c 28 00 0f 85 c4 01 00 00 49 8b 9c 24 d8 00 00 00 <80> 3a 00 0f 85 8f 01 00 00 4a 03 1c f9 48 89 d8 48 c1 e8 03 42 
RIP  [<ffffffff811f0d6c>] cpuacct_charge+0x14c/0x380 kernel/sched/cpuacct.c:247
 RSP <ffff8801c3dcf538>
CR2: fffffbfff331af20
---[ end trace ff3478891b0b46f2 ]---