linux-kernel - KMSAN: uninit-value in ip_tunnel

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Date:   Fri, 10 Aug 2018 07:30:03 -0700
From:   syzbot <syzbot+4a2c52677a8a1aa283cb@...kaller.appspotmail.com>
To:     davem@...emloft.net, kuznet@....inr.ac.ru,
        linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
        syzkaller-bugs@...glegroups.com, yoshfuji@...ux-ipv6.org
Subject: KMSAN: uninit-value in ip_tunnel_xmit (2)

Hello,

syzbot found the following crash on:

HEAD commit:    80ecacc456c1 kmsan: fix CONFIG_KMSAN=n build
git tree:       https://github.com/google/kmsan.git/master
console output: https://syzkaller.appspot.com/x/log.txt?x=163b7794400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=93d57043084eee38
dashboard link: https://syzkaller.appspot.com/bug?extid=4a2c52677a8a1aa283cb
compiler:       clang version 7.0.0 (trunk 334104)
syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=17cec9dc400000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=145dcf0c400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+4a2c52677a8a1aa283cb@...kaller.appspotmail.com

IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready
8021q: adding VLAN 0 to HW filter on device team0
==================================================================
BUG: KMSAN: uninit-value in ip_tunnel_xmit+0x63a/0x3b10  
net/ipv4/ip_tunnel.c:645
CPU: 1 PID: 4603 Comm: syz-executor712 Not tainted 4.18.0-rc4+ #27
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+0x185/0x1e0 lib/dump_stack.c:113
  kmsan_report+0x195/0x2c0 mm/kmsan/kmsan.c:982
  __msan_warning+0x7d/0xe0 mm/kmsan/kmsan_instr.c:645
  ip_tunnel_xmit+0x63a/0x3b10 net/ipv4/ip_tunnel.c:645
  __gre_xmit net/ipv4/ip_gre.c:449 [inline]
  ipgre_xmit+0xe16/0xef0 net/ipv4/ip_gre.c:701
  __netdev_start_xmit include/linux/netdevice.h:4148 [inline]
  netdev_start_xmit include/linux/netdevice.h:4157 [inline]
  xmit_one net/core/dev.c:3034 [inline]
  dev_hard_start_xmit+0x60f/0xcc0 net/core/dev.c:3050
  __dev_queue_xmit+0x3060/0x3c70 net/core/dev.c:3569
  dev_queue_xmit+0x4b/0x60 net/core/dev.c:3602
  packet_snd net/packet/af_packet.c:2919 [inline]
  packet_sendmsg+0x8469/0x9010 net/packet/af_packet.c:2944
  sock_sendmsg_nosec net/socket.c:641 [inline]
  sock_sendmsg net/socket.c:651 [inline]
  ___sys_sendmsg+0xed9/0x1350 net/socket.c:2125
  __sys_sendmsg net/socket.c:2163 [inline]
  __do_sys_sendmsg net/socket.c:2172 [inline]
  __se_sys_sendmsg net/socket.c:2170 [inline]
  __x64_sys_sendmsg+0x3b0/0x520 net/socket.c:2170
  do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:290
  entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x4412f9
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 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 db 0a fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffdc77f10d8 EFLAGS: 00000213 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004412f9
RDX: 0000000000000000 RSI: 0000000020000600 RDI: 0000000000000003
RBP: 00000000006cc018 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000020 R11: 0000000000000213 R12: 0000000000402260
R13: 00000000004022f0 R14: 0000000000000000 R15: 0000000000000000

Uninit was created at:
  kmsan_save_stack_with_flags mm/kmsan/kmsan.c:256 [inline]
  kmsan_internal_poison_shadow+0xc8/0x1d0 mm/kmsan/kmsan.c:181
  kmsan_kmalloc+0xa1/0x120 mm/kmsan/kmsan_hooks.c:91
  kmsan_slab_alloc+0x10/0x20 mm/kmsan/kmsan_hooks.c:100
  slab_post_alloc_hook mm/slab.h:446 [inline]
  slab_alloc_node mm/slub.c:2720 [inline]
  __kmalloc_node_track_caller+0xb48/0x11d0 mm/slub.c:4353
  __kmalloc_reserve net/core/skbuff.c:138 [inline]
  __alloc_skb+0x2cb/0x9e0 net/core/skbuff.c:206
  alloc_skb include/linux/skbuff.h:988 [inline]
  alloc_skb_with_frags+0x1e6/0xb80 net/core/skbuff.c:5271
  sock_alloc_send_pskb+0xb59/0x11e0 net/core/sock.c:2095
  packet_alloc_skb net/packet/af_packet.c:2776 [inline]
  packet_snd net/packet/af_packet.c:2867 [inline]
  packet_sendmsg+0x68cb/0x9010 net/packet/af_packet.c:2944
  sock_sendmsg_nosec net/socket.c:641 [inline]
  sock_sendmsg net/socket.c:651 [inline]
  ___sys_sendmsg+0xed9/0x1350 net/socket.c:2125
  __sys_sendmsg net/socket.c:2163 [inline]
  __do_sys_sendmsg net/socket.c:2172 [inline]
  __se_sys_sendmsg net/socket.c:2170 [inline]
  __x64_sys_sendmsg+0x3b0/0x520 net/socket.c:2170
  do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:290
  entry_SYSCALL_64_after_hwframe+0x63/0xe7
==================================================================


---
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