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BUG: KASAN: use-after-free in tls_fill_prepend include/net/tls.h:339 [inline]
BUG: KASAN: use-after-free in tls_push_record+0x10a9/0x1400 net/tls/tls_sw.c:235
Write of size 1 at addr ffff880193bde0bd by task syz-executor4/4879

CPU: 0 PID: 4879 Comm: syz-executor4 Not tainted 4.18.0-rc3+ #122
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113
 print_address_description+0x6c/0x20b mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412
 __asan_report_store1_noabort+0x17/0x20 mm/kasan/report.c:435
 tls_fill_prepend include/net/tls.h:339 [inline]
 tls_push_record+0x10a9/0x1400 net/tls/tls_sw.c:235
 tls_sw_sendmsg+0x9e6/0x12c0 net/tls/tls_sw.c:480
 inet_sendmsg+0x1a1/0x690 net/ipv4/af_inet.c:799
 sock_sendmsg_nosec net/socket.c:641 [inline]
 sock_sendmsg+0xd5/0x120 net/socket.c:651
 __sys_sendto+0x3d7/0x670 net/socket.c:1797
 __do_sys_sendto net/socket.c:1809 [inline]
 __se_sys_sendto net/socket.c:1805 [inline]
 __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1805
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x455ab9
Code: 1d ba fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 eb b9 fb ff c3 66 2e 0f 1f 84 00 00 00 00 
RSP: 002b:00007f9dee928c68 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f9dee9296d4 RCX: 0000000000455ab9
RDX: 00000000ffffff01 RSI: 0000000020000280 RDI: 0000000000000013
RBP: 000000000072bea0 R08: 0000000020000000 R09: 000000000000001c
R10: 0000000000008000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004c1164 R14: 00000000004d1860 R15: 0000000000000000

The buggy address belongs to the page:
page:ffffea00064ef780 count:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x2fffc0000000000()
raw: 02fffc0000000000 0000000000000000 ffffea00064ef788 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff880193bddf80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff880193bde000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff880193bde080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                        ^
 ffff880193bde100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff880193bde180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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