KASAN: slab-out-of-bounds Read in tls_push_record

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    739d0def85ca Merge branch 'hv_netvsc-Support-LRO-RSC-in-th..
git tree:       net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=13aa179e400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e79b9299baeb2298
dashboard link: https://syzkaller.appspot.com/bug?extid=942a1909765f0413329b
compiler:       gcc (GCC) 8.0.1 20180413 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+942a1909765f0413329b@xxxxxxxxxxxxxxxxxxxxxxxxx

==================================================================
BUG: KASAN: slab-out-of-bounds in sg_mark_end  
include/linux/scatterlist.h:195 [inline]
BUG: KASAN: slab-out-of-bounds in tls_push_record+0x1243/0x1330  
net/tls/tls_sw.c:521
Read of size 8 at addr ffff8801a4d235f8 by task syz-executor1/7668

CPU: 1 PID: 7668 Comm: syz-executor1 Not tainted 4.19.0-rc4+ #228
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+0x1c4/0x2b4 lib/dump_stack.c:113
 print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 sg_mark_end include/linux/scatterlist.h:195 [inline]
 tls_push_record+0x1243/0x1330 net/tls/tls_sw.c:521
 tls_sw_push_pending_record+0x22/0x30 net/tls/tls_sw.c:558
 tls_handle_open_record net/tls/tls_main.c:155 [inline]
 tls_sk_proto_close+0x439/0x750 net/tls/tls_main.c:272
 inet_release+0x104/0x1f0 net/ipv4/af_inet.c:428
 inet6_release+0x50/0x70 net/ipv6/af_inet6.c:458
 __sock_release+0xd7/0x250 net/socket.c:579
 sock_close+0x19/0x20 net/socket.c:1141
 __fput+0x385/0xa30 fs/file_table.c:278
 ____fput+0x15/0x20 fs/file_table.c:309
 task_work_run+0x1e8/0x2a0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:193 [inline]
 exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166
 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: 0033:0x411151
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 34 19 00 00 c3 48  
83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48  
89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007fff8ba9e200 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000411151
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
R10: 00007fff8ba9e130 R11: 0000000000000293 R12: 000000000000000f
R13: 0000000000086e3d R14: 0000000000000412 R15: badc0ffeebadface

Allocated by task 0:
(stack is not available)

Freed by task 0:
(stack is not available)

The buggy address belongs to the object at ffff8801a4d22d80
 which belongs to the cache kmalloc-2048 of size 2048
The buggy address is located 120 bytes to the right of
 2048-byte region [ffff8801a4d22d80, ffff8801a4d23580)
The buggy address belongs to the page:
page:ffffea0006934880 count:1 mapcount:0 mapping:ffff8801da800c40 index:0x0  
compound_mapcount: 0
flags: 0x2fffc0000008100(slab|head)
raw: 02fffc0000008100 ffffea000717fd08 ffff8801da801948 ffff8801da800c40
raw: 0000000000000000 ffff8801a4d22500 0000000100000003 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801a4d23480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8801a4d23500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ffff8801a4d23580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                                                ^
 ffff8801a4d23600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801a4d23680: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================


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