general protection fault in sit_exit_batch

general protection fault in sit_exit_batch_net
Status: upstream: reported C repro on 2019/10/02 21:50
Reported-by: syzbot+1695af5ca559927e2db8@syzkaller.appspotmail.com
First crash: 137d, last: 137d

Cause bisection: introduced by (bisect log):

commit ff92741270bf8b6e78aa885f166b68c7a67ab13a
Author: Jiri Pirko <jiri@mellanox.com>
Date: Mon Sep 30 09:48:15 2019 +0000

net: introduce name_node struct to be used in hashlist

Crash: general protection fault in sit_exit_batch_net (log)
Repro: C syz .config

Fix bisection: failed (bisect log)

Sample crash report:

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: 21 Comm: kworker/u4:1 Not tainted 5.3.0+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
RIP: 0010:dev_net include/linux/netdevice.h:2186 [inline]
RIP: 0010:sit_destroy_tunnels net/ipv6/sit.c:1831 [inline]
RIP: 0010:sit_exit_batch_net+0x3b1/0x750 net/ipv6/sit.c:1894
Code: fb 49 8d 7c 24 18 48 89 f8 48 c1 e8 03 80 3c 18 00 0f 85 27 02 00 00 4d 8b 44 24 18 49 8d b8 80 05 00 00 48 89 f8 48 c1 e8 03 <80> 3c 18 00 0f 85 f2 01 00 00 4d 3b a8 80 05 00 00 4c 89 85 58 ff
RSP: 0018:ffff8880a9a07b50 EFLAGS: 00010202
RAX: 00000000000000b0 RBX: dffffc0000000000 RCX: ffffffff865ad59f
RDX: 0000000000000000 RSI: ffffffff865ad488 RDI: 0000000000000580
RBP: ffff8880a9a07c08 R08: 0000000000000000 R09: fffffbfff1332f89
R10: fffffbfff1332f88 R11: ffffffff89997c47 R12: ffff88808b711140
R13: ffff88808f206300 R14: 0000000000000006 R15: ffff88808a9e8e50
FS:  0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000f8e000 CR3: 00000000980db000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 ops_exit_list.isra.0+0xfc/0x150 net/core/net_namespace.c:175
 cleanup_net+0x4e2/0xa60 net/core/net_namespace.c:594
 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 279fb1eb05d15843 ]---
RIP: 0010:dev_net include/linux/netdevice.h:2186 [inline]
RIP: 0010:sit_destroy_tunnels net/ipv6/sit.c:1831 [inline]
RIP: 0010:sit_exit_batch_net+0x3b1/0x750 net/ipv6/sit.c:1894
Code: fb 49 8d 7c 24 18 48 89 f8 48 c1 e8 03 80 3c 18 00 0f 85 27 02 00 00 4d 8b 44 24 18 49 8d b8 80 05 00 00 48 89 f8 48 c1 e8 03 <80> 3c 18 00 0f 85 f2 01 00 00 4d 3b a8 80 05 00 00 4c 89 85 58 ff
RSP: 0018:ffff8880a9a07b50 EFLAGS: 00010202
RAX: 00000000000000b0 RBX: dffffc0000000000 RCX: ffffffff865ad59f
RDX: 0000000000000000 RSI: ffffffff865ad488 RDI: 0000000000000580
RBP: ffff8880a9a07c08 R08: 0000000000000000 R09: fffffbfff1332f89
R10: fffffbfff1332f88 R11: ffffffff89997c47 R12: ffff88808b711140
R13: ffff88808f206300 R14: 0000000000000006 R15: ffff88808a9e8e50
FS:  0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000f8e000 CR3: 00000000980db000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Crashes (2):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	Maintainers
ci-upstream-net-kasan-gce	2019/10/02 20:18	net-next	c01ebd6c	2e29b534	.config	log	report	syz	C	davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-net-kasan-gce	2019/10/02 18:37	net-next	c01ebd6c	2e29b534	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org