KMSAN: uninit-value in bond_start_xmit (2)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    401f0ab26c43 kmsan: unpoison pages in do_read_cache_page()
git tree:       https://github.com/google/kmsan.git/master
console output: https://syzkaller.appspot.com/x/log.txt?x=17b808ae400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=6be230b6f0ad3490
dashboard link: https://syzkaller.appspot.com/bug?extid=e5be16aa39ad6e755391
compiler:       clang version 8.0.0 (trunk 339414)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=124d16da400000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=175f06be400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+e5be16aa39ad6e755391@xxxxxxxxxxxxxxxxxxxxxxxxx

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 bond_xmit_roundrobin  
drivers/net/bonding/bond_main.c:3858 [inline]
BUG: KMSAN: uninit-value in __bond_start_xmit  
drivers/net/bonding/bond_main.c:4136 [inline]
BUG: KMSAN: uninit-value in bond_start_xmit+0x1ab8/0x2b90  
drivers/net/bonding/bond_main.c:4170
CPU: 0 PID: 4319 Comm: syz-executor658 Not tainted 4.19.0-rc3+ #44
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+0x14b/0x190 lib/dump_stack.c:113
 kmsan_report+0x183/0x2b0 mm/kmsan/kmsan.c:956
 __msan_warning+0x70/0xc0 mm/kmsan/kmsan_instr.c:645
 bond_xmit_roundrobin drivers/net/bonding/bond_main.c:3858 [inline]
 __bond_start_xmit drivers/net/bonding/bond_main.c:4136 [inline]
 bond_start_xmit+0x1ab8/0x2b90 drivers/net/bonding/bond_main.c:4170
 __netdev_start_xmit include/linux/netdevice.h:4287 [inline]
 netdev_start_xmit include/linux/netdevice.h:4296 [inline]
 xmit_one net/core/dev.c:3216 [inline]
 dev_hard_start_xmit+0x5df/0xc20 net/core/dev.c:3232
 __dev_queue_xmit+0x2f35/0x3ab0 net/core/dev.c:3802
 dev_queue_xmit+0x4b/0x60 net/core/dev.c:3835
 packet_snd net/packet/af_packet.c:2925 [inline]
 packet_sendmsg+0x80ff/0x8c60 net/packet/af_packet.c:2950
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg net/socket.c:631 [inline]
 ___sys_sendmsg+0xe70/0x1290 net/socket.c:2114
 __sys_sendmsg net/socket.c:2152 [inline]
 __do_sys_sendmsg net/socket.c:2161 [inline]
 __se_sys_sendmsg+0x2a3/0x3d0 net/socket.c:2159
 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2159
 do_syscall_64+0xb8/0x100 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x4410f9
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:00007ffcc15c2468 EFLAGS: 00000217 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004410f9
RDX: 0000000000000000 RSI: 0000000020001940 RDI: 0000000000000004
RBP: 00000000006cc018 R08: 0000000000000100 R09: 0000000000000100
R10: 0000000000000100 R11: 0000000000000217 R12: 0000000000402060
R13: 00000000004020f0 R14: 0000000000000000 R15: 0000000000000000

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:256 [inline]
 kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:181
 kmsan_kmalloc+0x98/0x100 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:2718 [inline]
 __kmalloc_node_track_caller+0x9e7/0x1160 mm/slub.c:4351
 __kmalloc_reserve net/core/skbuff.c:138 [inline]
 __alloc_skb+0x2f5/0x9e0 net/core/skbuff.c:206
 alloc_skb include/linux/skbuff.h:996 [inline]
 alloc_skb_with_frags+0x1d0/0xac0 net/core/skbuff.c:5276
 sock_alloc_send_pskb+0xb47/0x1170 net/core/sock.c:2082
 packet_alloc_skb net/packet/af_packet.c:2779 [inline]
 packet_snd net/packet/af_packet.c:2870 [inline]
 packet_sendmsg+0x6599/0x8c60 net/packet/af_packet.c:2950
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg net/socket.c:631 [inline]
 ___sys_sendmsg+0xe70/0x1290 net/socket.c:2114
 __sys_sendmsg net/socket.c:2152 [inline]
 __do_sys_sendmsg net/socket.c:2161 [inline]
 __se_sys_sendmsg+0x2a3/0x3d0 net/socket.c:2159
 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2159
 do_syscall_64+0xb8/0x100 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
==================================================================


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxxx

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with  
syzbot.
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches