KASAN: slab-out-of-bounds Read in neigh_mark_dead

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 83af01ba1c2d Merge branch 'tc-testing-next'
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=119cd8b3400000
kernel config: https://syzkaller.appspot.com/x/.config?x=28ecefa8a6e10719
dashboard link: https://syzkaller.appspot.com/bug?extid=424d47d5c456ce8b2bbe
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+424d47...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-out-of-bounds in __list_del_entry_valid+0xf1/0x100
lib/list_debug.c:51
Read of size 8 at addr ffff8881cede7db0 by task kworker/0:3/6132

CPU: 0 PID: 6132 Comm: kworker/0:3 Not tainted 4.20.0-rc4+ #333
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: events_power_efficient neigh_periodic_work
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x244/0x39d lib/dump_stack.c:113
print_address_description.cold.7+0x9/0x1ff mm/kasan/report.c:256
kasan_report_error mm/kasan/report.c:354 [inline]
kasan_report.cold.8+0x242/0x309 mm/kasan/report.c:412
__asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
__list_del_entry_valid+0xf1/0x100 lib/list_debug.c:51
__list_del_entry include/linux/list.h:117 [inline]
list_del_init include/linux/list.h:159 [inline]
neigh_mark_dead+0x13b/0x410 net/core/neighbour.c:125
neigh_periodic_work+0x89a/0xc30 net/core/neighbour.c:905
process_one_work+0xc90/0x1c40 kernel/workqueue.c:2153
kobject: 'queues' (00000000e56310e9): kobject_add_internal:
parent: 'wlan340', set: '<NULL>'
kobject: 'queues' (00000000e56310e9): kobject_uevent_env
worker_thread+0x17f/0x1390 kernel/workqueue.c:2296
kobject: 'queues' (00000000e56310e9): kobject_uevent_env: filter function
caused the event to drop!
kobject: 'rx-0' (00000000ad997d75): kobject_add_internal: parent: 'queues',
set: 'queues'
kthread+0x35a/0x440 kernel/kthread.c:246
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
kobject: 'rx-0' (00000000ad997d75): kobject_uevent_env

Allocated by task 9759:
save_stack+0x43/0xd0 mm/kasan/kasan.c:448
set_track mm/kasan/kasan.c:460 [inline]
kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553
__do_kmalloc mm/slab.c:3722 [inline]
__kmalloc+0x15b/0x760 mm/slab.c:3731
kmalloc include/linux/slab.h:551 [inline]
kzalloc include/linux/slab.h:741 [inline]
__register_sysctl_table+0xc7/0xfb0 fs/proc/proc_sysctl.c:1307
register_net_sysctl+0x29/0x30 net/sysctl_net.c:120
kobject: 'rx-0' (00000000ad997d75): fill_kobj_path: path
= '/devices/virtual/mac80211_hwsim/hwsim1910/net/wlan340/queues/rx-0'
neigh_sysctl_register+0x399/0x730 net/core/neighbour.c:3430
devinet_sysctl_register+0xb4/0x220 net/ipv4/devinet.c:2520
inetdev_init+0x2df/0x590 net/ipv4/devinet.c:274
inetdev_event+0xf19/0x1340 net/ipv4/devinet.c:1479
notifier_call_chain+0x17e/0x380 kernel/notifier.c:93
__raw_notifier_call_chain kernel/notifier.c:394 [inline]
raw_notifier_call_chain+0x2d/0x40 kernel/notifier.c:401
call_netdevice_notifiers_info+0x3f/0x90 net/core/dev.c:1737
kobject: 'tx-0' (0000000014d217b7): kobject_add_internal: parent: 'queues',
set: 'queues'
call_netdevice_notifiers_extack net/core/dev.c:1749 [inline]
call_netdevice_notifiers net/core/dev.c:1763 [inline]
register_netdevice+0xb7d/0x11a0 net/core/dev.c:8615
ieee80211_if_add+0x1103/0x1ab0 net/mac80211/iface.c:1885
ieee80211_register_hw+0x351b/0x3f10 net/mac80211/main.c:1224
mac80211_hwsim_new_radio+0x1e48/0x3460
drivers/net/wireless/mac80211_hwsim.c:2887
hwsim_new_radio_nl+0x7dc/0xb20 drivers/net/wireless/mac80211_hwsim.c:3369
genl_family_rcv_msg+0x8a7/0x11a0 net/netlink/genetlink.c:601
genl_rcv_msg+0xc6/0x168 net/netlink/genetlink.c:626
kobject: 'tx-0' (0000000014d217b7): kobject_uevent_env
netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2477
genl_rcv+0x28/0x40 net/netlink/genetlink.c:637
netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
netlink_unicast+0x5a5/0x760 net/netlink/af_netlink.c:1336
netlink_sendmsg+0xa18/0xfc0 net/netlink/af_netlink.c:1917
sock_sendmsg_nosec net/socket.c:621 [inline]
sock_sendmsg+0xd5/0x120 net/socket.c:631
___sys_sendmsg+0x7fd/0x930 net/socket.c:2116
__sys_sendmsg+0x11d/0x280 net/socket.c:2154
kobject: 'tx-0' (0000000014d217b7): fill_kobj_path: path
= '/devices/virtual/mac80211_hwsim/hwsim1910/net/wlan340/queues/tx-0'
__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
entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 9:
save_stack+0x43/0xd0 mm/kasan/kasan.c:448
set_track mm/kasan/kasan.c:460 [inline]
__kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521
kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
__cache_free mm/slab.c:3498 [inline]
kfree+0xcf/0x230 mm/slab.c:3817
__rcu_reclaim kernel/rcu/rcu.h:233 [inline]
rcu_do_batch kernel/rcu/tree.c:2437 [inline]
invoke_rcu_callbacks kernel/rcu/tree.c:2716 [inline]
rcu_process_callbacks+0x1140/0x1ac0 kernel/rcu/tree.c:2697
kobject: 'tx-1' (00000000cb7aa8b1): kobject_add_internal: parent: 'queues',
set: 'queues'
__do_softirq+0x308/0xb7e kernel/softirq.c:292

The buggy address belongs to the object at ffff8881cede7b40
which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 624 bytes inside of
1024-byte region [ffff8881cede7b40, ffff8881cede7f40)
The buggy address belongs to the page:
page:ffffea00073b7980 count:1 mapcount:0 mapping:ffff8881da800ac0 index:0x0
compound_mapcount: 0
flags: 0x2fffc0000010200(slab|head)
raw: 02fffc0000010200 ffffea0006e35e88 ffffea0006ecdf08 ffff8881da800ac0
raw: 0000000000000000 ffff8881cede6040 0000000100000007 0000000000000000
page dumped because: kasan: bad access detected
kobject: 'tx-1' (00000000cb7aa8b1): kobject_uevent_env

Memory state around the buggy address:
ffff8881cede7c80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8881cede7d00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> ffff8881cede7d80: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff8881cede7e00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8881cede7e80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


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