general protection fault in tls_tx_records

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    ce96e791 Add linux-next specific files for 20190731
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=13ce4fd0600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=fca5b9d53db6585c
dashboard link: https://syzkaller.appspot.com/bug?extid=97d0cf528b9c8e9be7f4
compiler:       gcc (GCC) 9.0.0 20181231 (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+97d0cf528b9c8e9be7f4@xxxxxxxxxxxxxxxxxxxxxxxxx

kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.3.0-rc2-next-20190731 #56
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Workqueue: events tx_work_handler
RIP: 0010:tls_tx_records+0x5e/0x740 net/tls/tls_sw.c:365
Code: 80 3c 02 00 0f 85 31 06 00 00 49 8b 87 b0 06 00 00 48 8d 78 28 48 89  
45 c0 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f  
85 1b 06 00 00 48 8b 45 c0 48 8d 78 60 48 8b 58 28
RSP: 0018:ffff8880a98d7cb0 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000001 RCX: 1ffffffff134c016
RDX: 0000000000000005 RSI: ffffffff862e74fc RDI: 0000000000000028
RBP: ffff8880a98d7d00 R08: ffff8880a98c8300 R09: 0000000000000000
R10: fffffbfff134b9d8 R11: ffff8880a98c8300 R12: ffff88808eb47cc0
R13: ffff8880a9ac4c40 R14: ffff88808eb47de8 R15: ffff8880a9ac4c40
FS:  0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000001b30e80 CR3: 000000009c1a0000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 tx_work_handler+0x134/0x180 net/tls/tls_sw.c:2176
 process_one_work+0x9af/0x1740 kernel/workqueue.c:2269
 worker_thread+0x98/0xe40 kernel/workqueue.c:2415
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Modules linked in:
---[ end trace c75bda97ceb541bf ]---
RIP: 0010:tls_tx_records+0x5e/0x740 net/tls/tls_sw.c:365
Code: 80 3c 02 00 0f 85 31 06 00 00 49 8b 87 b0 06 00 00 48 8d 78 28 48 89  
45 c0 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f  
85 1b 06 00 00 48 8b 45 c0 48 8d 78 60 48 8b 58 28
RSP: 0018:ffff8880a98d7cb0 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000001 RCX: 1ffffffff134c016
RDX: 0000000000000005 RSI: ffffffff862e74fc RDI: 0000000000000028
RBP: ffff8880a98d7d00 R08: ffff8880a98c8300 R09: 0000000000000000
R10: fffffbfff134b9d8 R11: ffff8880a98c8300 R12: ffff88808eb47cc0
R13: ffff8880a9ac4c40 R14: ffff88808eb47de8 R15: ffff8880a9ac4c40
FS:  0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd4f4eadac CR3: 00000000987e6000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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