================================================================== BUG: KASAN: use-after-free in vlan_dev_get_iflink+0x6a/0x70 net/8021q/vlan_dev.c:767 Read of size 4 at addr ffff8880a8a7a100 by task syz-executor.5/16971 CPU: 1 PID: 16971 Comm: syz-executor.5 Not tainted 5.8.0-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+0x1f0/0x31e lib/dump_stack.c:118 print_address_description+0x66/0x620 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report+0x132/0x1d0 mm/kasan/report.c:530 vlan_dev_get_iflink+0x6a/0x70 net/8021q/vlan_dev.c:767 default_operstate net/core/link_watch.c:41 [inline] rfc2863_policy+0x11f/0x2a0 net/core/link_watch.c:53 linkwatch_do_dev+0x3a/0x160 net/core/link_watch.c:160 netdev_wait_allrefs net/core/dev.c:9991 [inline] netdev_run_todo+0x2c8/0xc90 net/core/dev.c:10087 rtnl_unlock net/core/rtnetlink.c:112 [inline] rtnetlink_rcv_msg+0x890/0xd40 net/core/rtnetlink.c:5564 netlink_rcv_skb+0x190/0x3a0 net/netlink/af_netlink.c:2470 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline] netlink_unicast+0x786/0x940 net/netlink/af_netlink.c:1330 netlink_sendmsg+0xa57/0xd70 net/netlink/af_netlink.c:1919 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg net/socket.c:671 [inline] ____sys_sendmsg+0x519/0x800 net/socket.c:2359 ___sys_sendmsg net/socket.c:2413 [inline] __sys_sendmsg+0x2b1/0x360 net/socket.c:2446 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45d189 Code: 5d b4 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 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f738ee13c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 000000000002c0c0 RCX: 000000000045d189 RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000004 RBP: 000000000118d020 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cfec R13: 00007ffd1a1c6c9f R14: 00007f738ee149c0 R15: 000000000118cfec Allocated by task 16959: kasan_save_stack mm/kasan/common.c:48 [inline] kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc+0x100/0x130 mm/kasan/common.c:461 kmalloc_node include/linux/slab.h:577 [inline] kvmalloc_node+0x81/0x110 mm/util.c:574 kvmalloc include/linux/mm.h:753 [inline] kvzalloc include/linux/mm.h:761 [inline] alloc_netdev_mqs+0x86/0xf90 net/core/dev.c:10251 rtnl_create_link+0x242/0x9c0 net/core/rtnetlink.c:3169 __rtnl_newlink net/core/rtnetlink.c:3431 [inline] rtnl_newlink+0x12a2/0x1c10 net/core/rtnetlink.c:3500 rtnetlink_rcv_msg+0x889/0xd40 net/core/rtnetlink.c:5563 netlink_rcv_skb+0x190/0x3a0 net/netlink/af_netlink.c:2470 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline] netlink_unicast+0x786/0x940 net/netlink/af_netlink.c:1330 netlink_sendmsg+0xa57/0xd70 net/netlink/af_netlink.c:1919 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg net/socket.c:671 [inline] ____sys_sendmsg+0x519/0x800 net/socket.c:2359 ___sys_sendmsg net/socket.c:2413 [inline] __sys_sendmsg+0x2b1/0x360 net/socket.c:2446 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 16988: kasan_save_stack mm/kasan/common.c:48 [inline] kasan_set_track+0x3d/0x70 mm/kasan/common.c:56 kasan_set_free_info+0x17/0x30 mm/kasan/generic.c:355 __kasan_slab_free+0xdd/0x110 mm/kasan/common.c:422 __cache_free mm/slab.c:3418 [inline] kfree+0x10a/0x220 mm/slab.c:3756 device_release+0x70/0x1a0 drivers/base/core.c:1796 kobject_cleanup lib/kobject.c:704 [inline] kobject_release lib/kobject.c:735 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x1a0/0x2c0 lib/kobject.c:752 netdev_run_todo+0xb17/0xc90 net/core/dev.c:10110 rtnl_unlock net/core/rtnetlink.c:112 [inline] rtnetlink_rcv_msg+0x890/0xd40 net/core/rtnetlink.c:5564 netlink_rcv_skb+0x190/0x3a0 net/netlink/af_netlink.c:2470 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline] netlink_unicast+0x786/0x940 net/netlink/af_netlink.c:1330 netlink_sendmsg+0xa57/0xd70 net/netlink/af_netlink.c:1919 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg net/socket.c:671 [inline] ____sys_sendmsg+0x519/0x800 net/socket.c:2359 ___sys_sendmsg net/socket.c:2413 [inline] __sys_sendmsg+0x2b1/0x360 net/socket.c:2446 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff8880a8a7a000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 256 bytes inside of 4096-byte region [ffff8880a8a7a000, ffff8880a8a7b000) The buggy address belongs to the page: page:00000000c392899d refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0xa8a7a head:00000000c392899d order:1 compound_mapcount:0 flags: 0xfffe0000010200(slab|head) raw: 00fffe0000010200 ffffea00023e1f88 ffffea00011a9108 ffff8880aa440900 raw: 0000000000000000 ffff8880a8a7a000 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a8a7a000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a8a7a080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880a8a7a100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880a8a7a180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a8a7a200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================