netlink: 24 bytes leftover after parsing attributes in process `syz-executor.3'.
netlink: 4 bytes leftover after parsing attributes in process `syz-executor.3'.
==================================================================
BUG: KASAN: use-after-free in macvlan_dev_get_iflink+0x5f/0x70 drivers/net/macvlan.c:1101
Read of size 4 at addr ffff8880a196a1c8 by task kworker/1:2/4312

CPU: 1 PID: 4312 Comm: kworker/1:2 Not tainted 4.14.289-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
Workqueue: events linkwatch_event
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x281 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252
 kasan_report_error.cold+0x8a/0x191 mm/kasan/report.c:351
 kasan_report mm/kasan/report.c:409 [inline]
 __asan_report_load4_noabort+0x68/0x70 mm/kasan/report.c:429
 macvlan_dev_get_iflink+0x5f/0x70 drivers/net/macvlan.c:1101
 dev_get_iflink+0x73/0xe0 net/core/dev.c:691
 rfc2863_policy+0x163/0x1b0 net/core/link_watch.c:43
 linkwatch_do_dev+0x1b/0x100 net/core/link_watch.c:157
 __linkwatch_run_queue+0x260/0x480 net/core/link_watch.c:202
 linkwatch_event+0x3c/0x50 net/core/link_watch.c:237
 process_one_work+0x793/0x14a0 kernel/workqueue.c:2117
 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2251
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404

Allocated by task 10426:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551
 __do_kmalloc_node mm/slab.c:3682 [inline]
 __kmalloc_node+0x4c/0x70 mm/slab.c:3689
 kmalloc_node include/linux/slab.h:530 [inline]
 kvmalloc_node+0x46/0xd0 mm/util.c:430
 kvmalloc include/linux/mm.h:531 [inline]
 kvzalloc include/linux/mm.h:539 [inline]
 alloc_netdev_mqs+0x76/0xb70 net/core/dev.c:8112
 rtnl_create_link+0x1ab/0x890 net/core/rtnetlink.c:2460
 rtnl_newlink+0xe7a/0x1830 net/core/rtnetlink.c:2720
 rtnetlink_rcv_msg+0x3be/0xb10 net/core/rtnetlink.c:4322
 netlink_rcv_skb+0x125/0x390 net/netlink/af_netlink.c:2454
 netlink_unicast_kernel net/netlink/af_netlink.c:1296 [inline]
 netlink_unicast+0x437/0x610 net/netlink/af_netlink.c:1322
 netlink_sendmsg+0x648/0xbc0 net/netlink/af_netlink.c:1893
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xb5/0x100 net/socket.c:656
 ___sys_sendmsg+0x6c8/0x800 net/socket.c:2062
 __sys_sendmsg+0xa3/0x120 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x27/0x40 net/socket.c:2103
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 10439:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xc3/0x1a0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xc9/0x250 mm/slab.c:3815
 kvfree+0x45/0x50 mm/util.c:449
 device_release+0x15f/0x1a0 drivers/base/core.c:848
 kobject_cleanup lib/kobject.c:646 [inline]
 kobject_release lib/kobject.c:675 [inline]
 kref_put include/linux/kref.h:70 [inline]
 kobject_put+0x251/0x550 lib/kobject.c:692
 netdev_run_todo+0x747/0xad0 net/core/dev.c:7969
 rtnl_unlock net/core/rtnetlink.c:106 [inline]
 rtnetlink_rcv_msg+0x3cb/0xb10 net/core/rtnetlink.c:4324
 netlink_rcv_skb+0x125/0x390 net/netlink/af_netlink.c:2454
 netlink_unicast_kernel net/netlink/af_netlink.c:1296 [inline]
 netlink_unicast+0x437/0x610 net/netlink/af_netlink.c:1322
 netlink_sendmsg+0x648/0xbc0 net/netlink/af_netlink.c:1893
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xb5/0x100 net/socket.c:656
 ___sys_sendmsg+0x6c8/0x800 net/socket.c:2062
 __sys_sendmsg+0xa3/0x120 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x27/0x40 net/socket.c:2103
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

The buggy address belongs to the object at ffff8880a196a0c0
 which belongs to the cache kmalloc-4096 of size 4096
The buggy address is located 264 bytes inside of
 4096-byte region [ffff8880a196a0c0, ffff8880a196b0c0)
The buggy address belongs to the page:
page:ffffea0002865a80 count:1 mapcount:0 mapping:ffff8880a196a0c0 index:0x0 compound_mapcount: 0
flags: 0xfff00000008100(slab|head)
raw: 00fff00000008100 ffff8880a196a0c0 0000000000000000 0000000100000001
raw: ffffea000150e4a0 ffffea00028cad20 ffff88813fe74dc0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a196a080: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
 ffff8880a196a100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880a196a180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                              ^
 ffff8880a196a200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a196a280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================