netlink: 4 bytes leftover after parsing attributes in process `syz-executor.3'. ================================================================== BUG: KASAN: use-after-free in vlan_dev_get_iflink+0x5f/0x70 net/8021q/vlan_dev.c:771 Read of size 4 at addr ffff88803f558888 by task syz-executor.3/6834 CPU: 1 PID: 6834 Comm: syz-executor.3 Not tainted 4.19.114-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x188/0x20d lib/dump_stack.c:118 print_address_description.cold+0x7c/0x212 mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report mm/kasan/report.c:412 [inline] kasan_report.cold+0x88/0x2b9 mm/kasan/report.c:396 vlan_dev_get_iflink+0x5f/0x70 net/8021q/vlan_dev.c:771 dev_get_iflink+0x73/0xe0 net/core/dev.c:691 rfc2863_policy+0x1ca/0x230 net/core/link_watch.c:43 linkwatch_do_dev+0x17/0x110 net/core/link_watch.c:157 linkwatch_forget_dev+0x16a/0x200 net/core/link_watch.c:223 netdev_wait_allrefs net/core/dev.c:8862 [inline] netdev_run_todo+0x242/0x740 net/core/dev.c:8958 rtnl_unlock net/core/rtnetlink.c:117 [inline] rtnetlink_rcv_msg+0x460/0xaf0 net/core/rtnetlink.c:4778 netlink_rcv_skb+0x160/0x410 net/netlink/af_netlink.c:2455 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x4d7/0x6a0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x80b/0xcd0 net/netlink/af_netlink.c:1909 sock_sendmsg_nosec net/socket.c:622 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:632 ___sys_sendmsg+0x803/0x920 net/socket.c:2115 __sys_sendmsg+0xec/0x1b0 net/socket.c:2153 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c889 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fd6b0da9c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fd6b0daa6d4 RCX: 000000000045c889 RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000006 RBP: 000000000076bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000009fe R14: 00000000004ccba4 R15: 000000000076bfac Allocated by task 6829: set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc mm/kasan/kasan.c:553 [inline] kasan_kmalloc+0xbf/0xe0 mm/kasan/kasan.c:531 __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:9122 rtnl_create_link+0x1d4/0xa30 net/core/rtnetlink.c:2869 rtnl_newlink+0xe1a/0x1440 net/core/rtnetlink.c:3131 rtnetlink_rcv_msg+0x453/0xaf0 net/core/rtnetlink.c:4777 netlink_rcv_skb+0x160/0x410 net/netlink/af_netlink.c:2455 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x4d7/0x6a0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x80b/0xcd0 net/netlink/af_netlink.c:1909 sock_sendmsg_nosec net/socket.c:622 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:632 ___sys_sendmsg+0x803/0x920 net/socket.c:2115 __sys_sendmsg+0xec/0x1b0 net/socket.c:2153 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 6829: set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0xf7/0x140 mm/kasan/kasan.c:521 __cache_free mm/slab.c:3503 [inline] kfree+0xce/0x220 mm/slab.c:3822 kvfree+0x59/0x60 mm/util.c:452 device_release+0x76/0x210 drivers/base/core.c:1061 kobject_cleanup lib/kobject.c:662 [inline] kobject_release lib/kobject.c:691 [inline] kref_put include/linux/kref.h:70 [inline] kobject_put+0x17c/0x270 lib/kobject.c:708 netdev_run_todo+0x4f1/0x740 net/core/dev.c:8981 rtnl_unlock net/core/rtnetlink.c:117 [inline] rtnetlink_rcv_msg+0x460/0xaf0 net/core/rtnetlink.c:4778 netlink_rcv_skb+0x160/0x410 net/netlink/af_netlink.c:2455 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x4d7/0x6a0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x80b/0xcd0 net/netlink/af_netlink.c:1909 sock_sendmsg_nosec net/socket.c:622 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:632 ___sys_sendmsg+0x803/0x920 net/socket.c:2115 __sys_sendmsg+0xec/0x1b0 net/socket.c:2153 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 ffff88803f558780 which belongs to the cache kmalloc-4096 of size 4096 The buggy address is located 264 bytes inside of 4096-byte region [ffff88803f558780, ffff88803f559780) The buggy address belongs to the page: page:ffffea0000fd5600 count:1 mapcount:0 mapping:ffff88812c3dcdc0 index:0x0 compound_mapcount: 0 flags: 0xfffe0000008100(slab|head) raw: 00fffe0000008100 ffffea0001019208 ffffea00024ab788 ffff88812c3dcdc0 raw: 0000000000000000 ffff88803f558780 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88803f558780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88803f558800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88803f558880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88803f558900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88803f558980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================