================================================================== BUG: KASAN: use-after-free in vlan_dev_get_iflink+0x5f/0x70 net/8021q/vlan_dev.c:767 Read of size 4 at addr ffff888094a76100 by task syz-executor015/9454 CPU: 1 PID: 9454 Comm: syz-executor015 Not tainted 5.8.0-rc6-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+0x18f/0x20d lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xae/0x436 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530 vlan_dev_get_iflink+0x5f/0x70 net/8021q/vlan_dev.c:767 dev_get_iflink+0x73/0xe0 net/core/dev.c:814 rfc2863_policy+0x243/0x2e0 net/core/link_watch.c:41 linkwatch_do_dev+0x2a/0x180 net/core/link_watch.c:160 linkwatch_forget_dev+0x16a/0x200 net/core/link_watch.c:237 netdev_wait_allrefs net/core/dev.c:9678 [inline] netdev_run_todo+0x258/0xac0 net/core/dev.c:9774 rtnl_unlock net/core/rtnetlink.c:112 [inline] rtnetlink_rcv_msg+0x45b/0xad0 net/core/rtnetlink.c:5461 netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2469 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline] netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1329 netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1918 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:672 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2352 ___sys_sendmsg+0xf3/0x170 net/socket.c:2406 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2439 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x446cf9 Code: Bad RIP value. RSP: 002b:00007f4a27e29d98 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00000000006dbc78 RCX: 0000000000446cf9 RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000006 RBP: 00000000006dbc70 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc7c R13: 0000000040000000 R14: 0000001000000000 R15: 0705001000000048 Allocated by task 9440: save_stack+0x1b/0x40 mm/kasan/common.c:48 set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:494 kmalloc_node include/linux/slab.h:578 [inline] kvmalloc_node+0x61/0xf0 mm/util.c:574 kvmalloc include/linux/mm.h:753 [inline] kvzalloc include/linux/mm.h:761 [inline] alloc_netdev_mqs+0x97/0xdc0 net/core/dev.c:9938 rtnl_create_link+0x219/0xad0 net/core/rtnetlink.c:3067 __rtnl_newlink+0xfa0/0x1730 net/core/rtnetlink.c:3329 rtnl_newlink+0x64/0xa0 net/core/rtnetlink.c:3397 rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5460 netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2469 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline] netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1329 netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1918 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:672 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2352 ___sys_sendmsg+0xf3/0x170 net/socket.c:2406 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2439 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 9461: save_stack+0x1b/0x40 mm/kasan/common.c:48 set_track mm/kasan/common.c:56 [inline] kasan_set_free_info mm/kasan/common.c:316 [inline] __kasan_slab_free+0xf5/0x140 mm/kasan/common.c:455 __cache_free mm/slab.c:3426 [inline] kfree+0x103/0x2c0 mm/slab.c:3757 kvfree+0x42/0x50 mm/util.c:603 device_release+0x71/0x200 drivers/base/core.c:1579 kobject_cleanup lib/kobject.c:693 [inline] kobject_release lib/kobject.c:722 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x1c0/0x270 lib/kobject.c:739 netdev_run_todo+0x765/0xac0 net/core/dev.c:9797 rtnl_unlock net/core/rtnetlink.c:112 [inline] rtnetlink_rcv_msg+0x45b/0xad0 net/core/rtnetlink.c:5461 netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2469 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline] netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1329 netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1918 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:672 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2352 ___sys_sendmsg+0xf3/0x170 net/socket.c:2406 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2439 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff888094a76000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 256 bytes inside of 4096-byte region [ffff888094a76000, ffff888094a77000) The buggy address belongs to the page: page:ffffea0002529d80 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 head:ffffea0002529d80 order:1 compound_mapcount:0 flags: 0xfffe0000010200(slab|head) raw: 00fffe0000010200 ffffea000251fe88 ffffea0002375c88 ffff8880aa002000 raw: 0000000000000000 ffff888094a76000 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888094a76000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888094a76080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888094a76100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888094a76180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888094a76200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================