Re: general protection fault in tls_write_space

[syzbot]

syzbot has found a reproducer for the following crash on:

HEAD commit:    ca497fb6 taprio: remove unused variable 'entry_list_policy'
git tree:       net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=109f3802600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d4cf1ffb87d590d7
dashboard link: https://syzkaller.appspot.com/bug?extid=dcdc9deefaec44785f32
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11c78cd2600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+dcdc9deefaec44785f32@xxxxxxxxxxxxxxxxxxxxxxxxx

kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 9 Comm: ksoftirqd/0 Not tainted 5.3.0-rc3+ #125
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
RIP: 0010:tls_write_space+0x51/0x170 net/tls/tls_main.c:239
Code: c1 ea 03 80 3c 02 00 0f 85 26 01 00 00 49 8b 9c 24 b0 06 00 00 48 b8  
00 00 00 00 00 fc ff df 48 8d 7b 6a 48 89 fa 48 c1 ea 03 <0f> b6 04 02 48  
89 fa 83 e2 07 38 d0 7f 08 84 c0 0f 85 df 00 00 00
RSP: 0018:ffff8880a98b74c8 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff860a27a2
RDX: 000000000000000d RSI: ffffffff862c86c1 RDI: 000000000000006a
RBP: ffff8880a98b74e0 R08: ffff8880a98a2240 R09: fffffbfff167c289
R10: fffffbfff167c288 R11: ffffffff8b3e1447 R12: ffff8880a4de41c0
R13: ffff8880a4de45b8 R14: 000000000000000a R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000008c9d1000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 tcp_new_space net/ipv4/tcp_input.c:5151 [inline]
 tcp_check_space+0x191/0x760 net/ipv4/tcp_input.c:5162
 tcp_data_snd_check net/ipv4/tcp_input.c:5172 [inline]
 tcp_rcv_state_process+0xe24/0x4e48 net/ipv4/tcp_input.c:6303
 tcp_v6_do_rcv+0x7d7/0x12c0 net/ipv6/tcp_ipv6.c:1381
 tcp_v6_rcv+0x31f1/0x3500 net/ipv6/tcp_ipv6.c:1588
 ip6_protocol_deliver_rcu+0x2fe/0x1660 net/ipv6/ip6_input.c:397
 ip6_input_finish+0x84/0x170 net/ipv6/ip6_input.c:438
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 ip6_input+0xe4/0x3f0 net/ipv6/ip6_input.c:447
 dst_input include/net/dst.h:442 [inline]
 ip6_rcv_finish+0x1de/0x2f0 net/ipv6/ip6_input.c:76
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 ipv6_rcv+0x10e/0x420 net/ipv6/ip6_input.c:272
 __netif_receive_skb_one_core+0x113/0x1a0 net/core/dev.c:5006
 __netif_receive_skb+0x2c/0x1d0 net/core/dev.c:5120
 process_backlog+0x206/0x750 net/core/dev.c:5951
 napi_poll net/core/dev.c:6388 [inline]
 net_rx_action+0x4d6/0x1080 net/core/dev.c:6456
 __do_softirq+0x262/0x98c kernel/softirq.c:292
 run_ksoftirqd kernel/softirq.c:603 [inline]
 run_ksoftirqd+0x8e/0x110 kernel/softirq.c:595
 smpboot_thread_fn+0x6a3/0xa40 kernel/smpboot.c:165
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Modules linked in:
---[ end trace c21a83505707bb9d ]---
RIP: 0010:tls_write_space+0x51/0x170 net/tls/tls_main.c:239
Code: c1 ea 03 80 3c 02 00 0f 85 26 01 00 00 49 8b 9c 24 b0 06 00 00 48 b8  
00 00 00 00 00 fc ff df 48 8d 7b 6a 48 89 fa 48 c1 ea 03 <0f> b6 04 02 48  
89 fa 83 e2 07 38 d0 7f 08 84 c0 0f 85 df 00 00 00
RSP: 0018:ffff8880a98b74c8 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff860a27a2
RDX: 000000000000000d RSI: ffffffff862c86c1 RDI: 000000000000006a
RBP: ffff8880a98b74e0 R08: ffff8880a98a2240 R09: fffffbfff167c289
R10: fffffbfff167c288 R11: ffffffff8b3e1447 R12: ffff8880a4de41c0
R13: ffff8880a4de45b8 R14: 000000000000000a R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000008c9d1000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400