Re: [syzbot] possible deadlock in console_lock_spinning_enable (2)

syzbot
2022-06-20T11:10:47Z

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
UBSAN: object-size-mismatch in wg_xmit

IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_batadv: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): macvtap0: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready
================================================================================
UBSAN: object-size-mismatch in ./include/linux/skbuff.h:2085:28
member access within address ffffc9000278f420 with insufficient space
for an object of type 'struct sk_buff'
CPU: 1 PID: 3626 Comm: kworker/1:6 Not tainted 5.16.0-rc4-syzkaller-00161-gc741e49150db-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: ipv6_addrconf addrconf_dad_work
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
ubsan_epilogue lib/ubsan.c:151 [inline]
handle_object_size_mismatch lib/ubsan.c:232 [inline]
ubsan_type_mismatch_common+0x1e6/0x390 lib/ubsan.c:245
__ubsan_handle_type_mismatch_v1+0x4a/0x60 lib/ubsan.c:274
__skb_queue_before include/linux/skbuff.h:2085 [inline]
__skb_queue_tail include/linux/skbuff.h:2118 [inline]
wg_xmit+0x565/0xda0 drivers/net/wireguard/device.c:185
__netdev_start_xmit include/linux/netdevice.h:4994 [inline]
netdev_start_xmit+0x7b/0x140 include/linux/netdevice.h:5008
xmit_one net/core/dev.c:3590 [inline]
dev_hard_start_xmit+0x182/0x2e0 net/core/dev.c:3606
__dev_queue_xmit+0x158e/0x2540 net/core/dev.c:4229
neigh_output include/net/neighbour.h:527 [inline]
ip6_finish_output2+0xf45/0x1300 net/ipv6/ip6_output.c:126
dst_output include/net/dst.h:450 [inline]
NF_HOOK include/linux/netfilter.h:307 [inline]
ndisc_send_skb+0x8c3/0xdd0 net/ipv6/ndisc.c:508
addrconf_dad_completed+0x543/0xa70 net/ipv6/addrconf.c:4216
addrconf_dad_work+0xbd8/0x1450
process_one_work+0x4ea/0x920 kernel/workqueue.c:2298
worker_thread+0x686/0x9e0 kernel/workqueue.c:2445
kthread+0x35c/0x430 kernel/kthread.c:327
ret_from_fork+0x1f/0x30
</TASK>
================================================================================

Tested on:

commit: c741e491 Merge tag 'for-linus' of git://git.kernel.org..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=11102217f00000
kernel config: https://syzkaller.appspot.com/x/.config?x=308b87e56290f642
dashboard link: https://syzkaller.appspot.com/bug?extid=3cc1054e15babd5f4cd2
compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
patch: https://syzkaller.appspot.com/x/patch.diff?x=1117be40080000