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BUG: KASAN: use-after-free in macvlan_dev_get_iflink+0x5f/0x70 drivers/net/macvlan.c:1099
Read of size 4 at addr ffff88805969cbc8 by task kworker/1:2/11175
UDF-fs: INFO Mounting volume 'LinuxUDF', timestamp 2020/09/19 18:44 (1000)

CPU: 1 PID: 11175 Comm: kworker/1:2 Not tainted 4.19.211-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:77 [inline]
 dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
 print_address_description.cold+0x54/0x219 mm/kasan/report.c:256
 kasan_report_error.cold+0x8a/0x1b9 mm/kasan/report.c:354
 kasan_report mm/kasan/report.c:412 [inline]
 __asan_report_load4_noabort+0x88/0x90 mm/kasan/report.c:432
 macvlan_dev_get_iflink+0x5f/0x70 drivers/net/macvlan.c:1099
 dev_get_iflink+0x73/0xe0 net/core/dev.c:692
 rfc2863_policy+0x1af/0x200 net/core/link_watch.c:43
 linkwatch_do_dev+0x1d/0x110 net/core/link_watch.c:157
 __linkwatch_run_queue+0x22d/0x5d0 net/core/link_watch.c:202
 linkwatch_event+0x4a/0x60 net/core/link_watch.c:237
 process_one_work+0x864/0x1570 kernel/workqueue.c:2153
 worker_thread+0x64c/0x1130 kernel/workqueue.c:2296
 kthread+0x33f/0x460 kernel/kthread.c:259
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415

Allocated by task 25508:
 __do_kmalloc_node mm/slab.c:3689 [inline]
 __kmalloc_node+0x4c/0x70 mm/slab.c:3696
 kmalloc_node include/linux/slab.h:557 [inline]
 kvmalloc_node+0x61/0xf0 mm/util.c:423
 kvmalloc include/linux/mm.h:577 [inline]
 kvzalloc include/linux/mm.h:585 [inline]
 alloc_netdev_mqs+0x97/0xd50 net/core/dev.c:9152
 rtnl_create_link+0x1d4/0xa40 net/core/rtnetlink.c:2869
 rtnl_newlink+0xf45/0x15c0 net/core/rtnetlink.c:3131
 rtnetlink_rcv_msg+0x453/0xb80 net/core/rtnetlink.c:4782
 netlink_rcv_skb+0x160/0x440 net/netlink/af_netlink.c:2463
 netlink_unicast_kernel net/netlink/af_netlink.c:1325 [inline]
 netlink_unicast+0x4d5/0x690 net/netlink/af_netlink.c:1351
 netlink_sendmsg+0x6c3/0xc50 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg+0xc3/0x120 net/socket.c:661
 ___sys_sendmsg+0x7bb/0x8e0 net/socket.c:2227
 __sys_sendmsg net/socket.c:2265 [inline]
 __do_sys_sendmsg net/socket.c:2274 [inline]
 __se_sys_sendmsg net/socket.c:2272 [inline]
 __x64_sys_sendmsg+0x132/0x220 net/socket.c:2272
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 25523:
 __cache_free mm/slab.c:3503 [inline]
 kfree+0xcc/0x210 mm/slab.c:3822
 kvfree+0x59/0x60 mm/util.c:452
 device_release+0x76/0x210 drivers/base/core.c:1076
 kobject_cleanup lib/kobject.c:662 [inline]
 kobject_release lib/kobject.c:691 [inline]
 kref_put include/linux/kref.h:70 [inline]
 kobject_put+0x28b/0x5d0 lib/kobject.c:708
 netdev_run_todo+0x77f/0xab0 net/core/dev.c:9011
 rtnl_unlock net/core/rtnetlink.c:117 [inline]
 rtnetlink_rcv_msg+0x460/0xb80 net/core/rtnetlink.c:4783
 netlink_rcv_skb+0x160/0x440 net/netlink/af_netlink.c:2463
 netlink_unicast_kernel net/netlink/af_netlink.c:1325 [inline]
 netlink_unicast+0x4d5/0x690 net/netlink/af_netlink.c:1351
 netlink_sendmsg+0x6c3/0xc50 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg+0xc3/0x120 net/socket.c:661
 ___sys_sendmsg+0x7bb/0x8e0 net/socket.c:2227
 __sys_sendmsg net/socket.c:2265 [inline]
 __do_sys_sendmsg net/socket.c:2274 [inline]
 __se_sys_sendmsg net/socket.c:2272 [inline]
 __x64_sys_sendmsg+0x132/0x220 net/socket.c:2272
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff88805969cac0
 which belongs to the cache kmalloc-4096 of size 4096
The buggy address is located 264 bytes inside of
 4096-byte region [ffff88805969cac0, ffff88805969dac0)
The buggy address belongs to the page:
page:ffffea000165a700 count:1 mapcount:0 mapping:ffff88813bff0dc0 index:0x0 compound_mapcount: 0
flags: 0xfff00000008100(slab|head)
raw: 00fff00000008100 ffffea0002afac88 ffffea000166e208 ffff88813bff0dc0
raw: 0000000000000000 ffff88805969cac0 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88805969ca80: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
 ffff88805969cb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88805969cb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                              ^
 ffff88805969cc00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805969cc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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