================================================================== BUG: KASAN: use-after-free in macvlan_dev_get_iflink+0x5f/0x70 drivers/net/macvlan.c:1099 Read of size 4 at addr ffff88804a7a4648 by task kworker/0:3/8998 CPU: 0 PID: 8998 Comm: kworker/0:3 Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022 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 21830: __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 21858: __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 ffff88804a7a4540 which belongs to the cache kmalloc-4096 of size 4096 The buggy address is located 264 bytes inside of 4096-byte region [ffff88804a7a4540, ffff88804a7a5540) The buggy address belongs to the page: page:ffffea000129e900 count:1 mapcount:0 mapping:ffff88813bff0dc0 index:0x0 compound_mapcount: 0 flags: 0xfff00000008100(slab|head) raw: 00fff00000008100 ffffea000286d308 ffffea0001391c88 ffff88813bff0dc0 raw: 0000000000000000 ffff88804a7a4540 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88804a7a4500: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ffff88804a7a4580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88804a7a4600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88804a7a4680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88804a7a4700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================