================================================================== BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:199 [inline] BUG: KASAN: use-after-free in __in6_dev_get include/net/addrconf.h:309 [inline] BUG: KASAN: use-after-free in ip6_ignore_linkdown include/net/addrconf.h:400 [inline] BUG: KASAN: use-after-free in find_match+0xb39/0xc90 net/ipv6/route.c:749 Read of size 8 at addr ffff888098fc8320 by task syz-executor853/9717 CPU: 0 PID: 9717 Comm: syz-executor853 Not tainted 5.6.0-rc2-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+0x197/0x210 lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374 __kasan_report.cold+0x1b/0x32 mm/kasan/report.c:506 kasan_report+0x12/0x20 mm/kasan/common.c:641 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135 __read_once_size include/linux/compiler.h:199 [inline] __in6_dev_get include/net/addrconf.h:309 [inline] ip6_ignore_linkdown include/net/addrconf.h:400 [inline] find_match+0xb39/0xc90 net/ipv6/route.c:749 __find_rr_leaf+0x14e/0x750 net/ipv6/route.c:837 find_rr_leaf net/ipv6/route.c:858 [inline] rt6_select net/ipv6/route.c:902 [inline] fib6_table_lookup+0x697/0xdb0 net/ipv6/route.c:2170 ip6_pol_route+0x1f6/0xa70 net/ipv6/route.c:2206 ip6_pol_route_input+0x65/0x80 net/ipv6/route.c:2264 fib6_rule_lookup+0x133/0x7d0 net/ipv6/fib6_rules.c:114 ip6_route_input_lookup+0xb7/0xd0 net/ipv6/route.c:2276 ip6_route_input+0x5f0/0xa40 net/ipv6/route.c:2445 ip6_rcv_finish_core.isra.0+0x174/0x590 net/ipv6/ip6_input.c:63 ip6_rcv_finish+0x17a/0x310 net/ipv6/ip6_input.c:74 NF_HOOK include/linux/netfilter.h:307 [inline] NF_HOOK include/linux/netfilter.h:301 [inline] ipv6_rcv+0x10e/0x420 net/ipv6/ip6_input.c:306 __netif_receive_skb_one_core+0x113/0x1a0 net/core/dev.c:5198 __netif_receive_skb+0x2c/0x1d0 net/core/dev.c:5312 process_backlog+0x226/0x780 net/core/dev.c:6144 napi_poll net/core/dev.c:6582 [inline] net_rx_action+0x508/0x1120 net/core/dev.c:6650 __do_softirq+0x262/0x98c kernel/softirq.c:292 do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1082 do_softirq.part.0+0x11a/0x170 kernel/softirq.c:337 do_softirq kernel/softirq.c:329 [inline] __local_bh_enable_ip+0x211/0x270 kernel/softirq.c:189 local_bh_enable include/linux/bottom_half.h:32 [inline] get_next_corpse net/netfilter/nf_conntrack_core.c:2012 [inline] nf_ct_iterate_cleanup+0x212/0x4e0 net/netfilter/nf_conntrack_core.c:2035 nf_ct_iterate_cleanup_net net/netfilter/nf_conntrack_core.c:2120 [inline] nf_ct_iterate_cleanup_net+0x133/0x190 net/netfilter/nf_conntrack_core.c:2105 masq_device_event+0xb5/0xe0 net/netfilter/nf_nat_masquerade.c:88 notifier_call_chain+0xc2/0x230 kernel/notifier.c:83 __raw_notifier_call_chain kernel/notifier.c:361 [inline] raw_notifier_call_chain+0x2e/0x40 kernel/notifier.c:368 call_netdevice_notifiers_info net/core/dev.c:1943 [inline] call_netdevice_notifiers_info+0xba/0x130 net/core/dev.c:1928 call_netdevice_notifiers_extack net/core/dev.c:1955 [inline] call_netdevice_notifiers net/core/dev.c:1969 [inline] dev_close_many+0x32a/0x6c0 net/core/dev.c:1544 rollback_registered_many+0x42e/0x1030 net/core/dev.c:8797 rollback_registered+0x109/0x1d0 net/core/dev.c:8865 unregister_netdevice_queue net/core/dev.c:9957 [inline] unregister_netdevice_queue+0x1ee/0x2c0 net/core/dev.c:9950 unregister_netdevice include/linux/netdevice.h:2713 [inline] __tun_detach+0xe6d/0x1150 drivers/net/tun.c:723 tun_detach drivers/net/tun.c:740 [inline] tun_chr_close+0xe0/0x180 drivers/net/tun.c:3459 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xba9/0x2f50 kernel/exit.c:801 do_group_exit+0x135/0x360 kernel/exit.c:899 __do_sys_exit_group kernel/exit.c:910 [inline] __se_sys_exit_group kernel/exit.c:908 [inline] __ia32_sys_exit_group+0x44/0x50 kernel/exit.c:908 do_syscall_32_irqs_on arch/x86/entry/common.c:337 [inline] do_fast_syscall_32+0x27b/0xe16 arch/x86/entry/common.c:408 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 RIP: 0023:0xf7fc1e39 Code: Bad RIP value. RSP: 002b:00000000fff41efc EFLAGS: 00000296 ORIG_RAX: 00000000000000fc RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00000000080f7b18 RDX: 0000000000000000 RSI: 00000000080dfc1c RDI: 00000000080f7b20 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 9717: save_stack+0x23/0x90 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] __kasan_kmalloc mm/kasan/common.c:515 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:488 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:529 __do_kmalloc_node mm/slab.c:3616 [inline] __kmalloc_node+0x4e/0x70 mm/slab.c:3623 kmalloc_node include/linux/slab.h:578 [inline] kvmalloc_node+0x68/0x100 mm/util.c:574 kvmalloc include/linux/mm.h:645 [inline] kvzalloc include/linux/mm.h:653 [inline] alloc_netdev_mqs+0x98/0xe40 net/core/dev.c:9797 rtnl_create_link+0x22d/0xaf0 net/core/rtnetlink.c:3047 __rtnl_newlink+0xf9f/0x1790 net/core/rtnetlink.c:3309 rtnl_newlink+0x69/0xa0 net/core/rtnetlink.c:3377 rtnetlink_rcv_msg+0x45e/0xaf0 net/core/rtnetlink.c:5438 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5456 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x59e/0x7e0 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:672 __sys_sendto+0x262/0x380 net/socket.c:1998 __do_compat_sys_socketcall net/compat.c:771 [inline] __se_compat_sys_socketcall net/compat.c:719 [inline] __ia32_compat_sys_socketcall+0x530/0x710 net/compat.c:719 do_syscall_32_irqs_on arch/x86/entry/common.c:337 [inline] do_fast_syscall_32+0x27b/0xe16 arch/x86/entry/common.c:408 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 Freed by task 9717: save_stack+0x23/0x90 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] kasan_set_free_info mm/kasan/common.c:337 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:476 kasan_slab_free+0xe/0x10 mm/kasan/common.c:485 __cache_free mm/slab.c:3426 [inline] kfree+0x10a/0x2c0 mm/slab.c:3757 __netdev_name_node_alt_destroy+0x1ff/0x2a0 net/core/dev.c:322 netdev_name_node_alt_destroy+0x57/0x80 net/core/dev.c:334 rtnl_alt_ifname net/core/rtnetlink.c:3518 [inline] rtnl_linkprop.isra.0+0x575/0x6f0 net/core/rtnetlink.c:3567 rtnl_dellinkprop+0x46/0x60 net/core/rtnetlink.c:3588 rtnetlink_rcv_msg+0x45e/0xaf0 net/core/rtnetlink.c:5438 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5456 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x59e/0x7e0 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:672 ____sys_sendmsg+0x753/0x880 net/socket.c:2343 ___sys_sendmsg+0x100/0x170 net/socket.c:2397 __sys_sendmsg+0x105/0x1d0 net/socket.c:2430 __compat_sys_sendmsg net/compat.c:642 [inline] __do_compat_sys_sendmsg net/compat.c:649 [inline] __se_compat_sys_sendmsg net/compat.c:646 [inline] __ia32_compat_sys_sendmsg+0x7a/0xb0 net/compat.c:646 do_syscall_32_irqs_on arch/x86/entry/common.c:337 [inline] do_fast_syscall_32+0x27b/0xe16 arch/x86/entry/common.c:408 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 The buggy address belongs to the object at ffff888098fc8000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 800 bytes inside of 4096-byte region [ffff888098fc8000, ffff888098fc9000) The buggy address belongs to the page: page:ffffea000263f200 refcount:1 mapcount:0 mapping:ffff8880aa402000 index:0x0 compound_mapcount: 0 flags: 0xfffe0000010200(slab|head) raw: 00fffe0000010200 ffffea0002696c08 ffffea00027e5f88 ffff8880aa402000 raw: 0000000000000000 ffff888098fc8000 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888098fc8200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888098fc8280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888098fc8300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888098fc8380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888098fc8400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================