general protection fault in xfrm_policy_insert_list

From: syzbot
Date: Mon Dec 24 2018 - 10:24:08 EST

Hello,

syzbot found the following crash on:

HEAD commit: ce28bb445388 Merge git://git.kernel.org/pub/scm/linux/kern..
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=17803ac3400000
kernel config: https://syzkaller.appspot.com/x/.config?x=67a2081147a23142
dashboard link: https://syzkaller.appspot.com/bug?extid=e879931aaae5c1abca56
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+e879931aaae5c1abca56@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: 1 PID: 6146 Comm: syz-executor5 Not tainted 4.20.0-rc7+ #358
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:xfrm_policy_insert_list+0x174/0x1020 net/xfrm/xfrm_policy.c:1532
kobject: 'loop0' (000000008b3a9204): kobject_uevent_env
Code: ff ff ff 48 c1 e8 03 4c 01 e0 48 89 85 20 ff ff ff e8 40 d6 b3 fa 48 8d bb 19 02 00 00 48 89 f8 48 89 fa 48 c1 e8 03 83 e2 07 <42> 0f b6 04 20 38 d0 7f 08 84 c0 0f 85 f5 0b 00 00 44 0f b6 ab 19
RSP: 0018:ffff88819772f098 EFLAGS: 00010202
RAX: 00000025800000bf RBX: 0000012c000003e0 RCX: ffffc9000fe54000
RDX: 0000000000000001 RSI: ffffffff86cae280 RDI: 0000012c000005f9
kobject: 'loop0' (000000008b3a9204): fill_kobj_path: path = '/devices/virtual/block/loop0'
RBP: ffff88819772f1c0 R08: ffff8881d32c2480 R09: 1ffff11037615f21
R10: 0000000000000003 R11: ffff888192b2a600 R12: dffffc0000000000
R13: 0000000000000000 R14: 000000008bc53300 R15: 0000000000000000
FS: 00007fb18f7ca700(0000) GS:ffff8881daf00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
kobject: 'loop3' (00000000bef5b68b): kobject_uevent_env
CR2: 00000000004d9300 CR3: 0000000180ff1000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
kobject: 'loop3' (00000000bef5b68b): fill_kobj_path: path = '/devices/virtual/block/loop3'
xfrm_policy_inexact_insert+0x166/0xee0 net/xfrm/xfrm_policy.c:1195
kobject: 'loop0' (000000008b3a9204): kobject_uevent_env
kobject: 'loop0' (000000008b3a9204): fill_kobj_path: path = '/devices/virtual/block/loop0'
xfrm_policy_insert+0x639/0x850 net/xfrm/xfrm_policy.c:1570
xfrm_add_policy+0x2a0/0x6f0 net/xfrm/xfrm_user.c:1657
kobject: 'loop2' (000000000496a7a1): kobject_uevent_env
xfrm_user_rcv_msg+0x44c/0x8e0 net/xfrm/xfrm_user.c:2663
kobject: 'loop2' (000000000496a7a1): fill_kobj_path: path = '/devices/virtual/block/loop2'
netlink_rcv_skb+0x16c/0x430 net/netlink/af_netlink.c:2477
xfrm_netlink_rcv+0x6f/0x90 net/xfrm/xfrm_user.c:2671
netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
netlink_unicast+0x59f/0x750 net/netlink/af_netlink.c:1336
netlink_sendmsg+0xa18/0xfc0 net/netlink/af_netlink.c:1917
kobject: 'loop2' (000000000496a7a1): kobject_uevent_env
sock_sendmsg_nosec net/socket.c:621 [inline]
sock_sendmsg+0xd5/0x120 net/socket.c:631
___sys_sendmsg+0x7fd/0x930 net/socket.c:2116
kobject: 'loop2' (000000000496a7a1): fill_kobj_path: path = '/devices/virtual/block/loop2'
kobject: 'loop0' (000000008b3a9204): kobject_uevent_env
kobject: 'loop0' (000000008b3a9204): fill_kobj_path: path = '/devices/virtual/block/loop0'
__sys_sendmsg+0x11d/0x280 net/socket.c:2154
kobject: 'loop2' (000000000496a7a1): kobject_uevent_env
__do_sys_sendmsg net/socket.c:2163 [inline]
__se_sys_sendmsg net/socket.c:2161 [inline]
__x64_sys_sendmsg+0x78/0xb0 net/socket.c:2161
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
kobject: 'loop2' (000000000496a7a1): fill_kobj_path: path = '/devices/virtual/block/loop2'
kobject: 'loop0' (000000008b3a9204): kobject_uevent_env
kobject: 'loop0' (000000008b3a9204): fill_kobj_path: path = '/devices/virtual/block/loop0'
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457669
Code: fd b3 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 b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fb18f7c9c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457669
kobject: 'loop2' (000000000496a7a1): kobject_uevent_env
RDX: 0000000000000000 RSI: 000000002014f000 RDI: 0000000000000003
RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb18f7ca6d4
R13: 00000000004c44d8 R14: 00000000004d74e8 R15: 00000000ffffffff
Modules linked in:
---[ end trace 818a477ec48fd0a4 ]---
kobject: 'loop2' (000000000496a7a1): fill_kobj_path: path = '/devices/virtual/block/loop2'
RIP: 0010:xfrm_policy_insert_list+0x174/0x1020 net/xfrm/xfrm_policy.c:1532
Code: ff ff ff 48 c1 e8 03 4c 01 e0 48 89 85 20 ff ff ff e8 40 d6 b3 fa 48 8d bb 19 02 00 00 48 89 f8 48 89 fa 48 c1 e8 03 83 e2 07 <42> 0f b6 04 20 38 d0 7f 08 84 c0 0f 85 f5 0b 00 00 44 0f b6 ab 19
RSP: 0018:ffff88819772f098 EFLAGS: 00010202
RAX: 00000025800000bf RBX: 0000012c000003e0 RCX: ffffc9000fe54000
RDX: 0000000000000001 RSI: ffffffff86cae280 RDI: 0000012c000005f9
RBP: ffff88819772f1c0 R08: ffff8881d32c2480 R09: 1ffff11037615f21
R10: 0000000000000003 R11: ffff888192b2a600 R12: dffffc0000000000
R13: 0000000000000000 R14: 000000008bc53300 R15: 0000000000000000
FS: 00007fb18f7ca700(0000) GS:ffff8881daf00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004d9300 CR3: 0000000180ff1000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
kobject: 'loop2' (000000000496a7a1): kobject_uevent_env
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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