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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+0x1091/0x1400 net/tls/tls_sw.c:239
Write of size 1 at addr ffff8801b6c20000 by task syz-executor7/3357

CPU: 0 PID: 3357 Comm: syz-executor7 Not tainted 4.18.0-rc7+ #42
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+0x1091/0x1400 net/tls/tls_sw.c:239
 tls_sw_push_pending_record+0x22/0x30 net/tls/tls_sw.c:276
 tls_handle_open_record net/tls/tls_main.c:164 [inline]
 tls_sk_proto_close+0x74c/0xae0 net/tls/tls_main.c:264
 inet_release+0x104/0x1f0 net/ipv4/af_inet.c:427
 inet6_release+0x50/0x70 net/ipv6/af_inet6.c:459
 __sock_release+0xd7/0x260 net/socket.c:600
 sock_close+0x19/0x20 net/socket.c:1151
 __fput+0x355/0x8b0 fs/file_table.c:209
 ____fput+0x15/0x20 fs/file_table.c:243
 task_work_run+0x1ec/0x2a0 kernel/task_work.c:113
 get_signal+0x1559/0x1970 kernel/signal.c:2298
 do_signal+0x9c/0x21c0 arch/x86/kernel/signal.c:816
 exit_to_usermode_loop+0x2e0/0x370 arch/x86/entry/common.c:162
 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
 do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x456b29
Code: fd b4 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 cb b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 
RSP: 002b:00007fc73ca4dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: 0000000000000001 RBX: 00007fc73ca4e6d4 RCX: 0000000000456b29
RDX: 0000000000000001 RSI: 0000000020005f00 RDI: 0000000000000014
RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000016
R13: 00000000004d3158 R14: 00000000004c7ec1 R15: 0000000000000003

The buggy address belongs to the page:
page:ffffea0006db0800 count:0 mapcount:-128 mapping:0000000000000000 index:0x0
flags: 0x2fffc0000000000()
raw: 02fffc0000000000 ffffea0006cc1808 ffff88021fffac18 0000000000000000
raw: 0000000000000000 0000000000000003 00000000ffffff7f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801b6c1ff00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff8801b6c1ff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8801b6c20000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff8801b6c20080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8801b6c20100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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