================================================================== BUG: KASAN: use-after-free in __fib6_clean_all+0x296/0x2a0 net/ipv6/ip6_fib.c:2255 Read of size 8 at addr ffff888026e39000 by task syz-executor.4/3639 CPU: 1 PID: 3639 Comm: syz-executor.4 Not tainted 6.0.0-rc3-syzkaller-00545-gc3f760ef1287 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:317 [inline] print_report.cold+0x2ba/0x719 mm/kasan/report.c:433 kasan_report+0xb1/0x1e0 mm/kasan/report.c:495 __fib6_clean_all+0x296/0x2a0 net/ipv6/ip6_fib.c:2255 rt6_sync_down_dev net/ipv6/route.c:4894 [inline] rt6_disable_ip+0x8a1/0xaa0 net/ipv6/route.c:4899 addrconf_ifdown.isra.0+0x11a/0x1830 net/ipv6/addrconf.c:3746 addrconf_notify+0xeb/0x1b90 net/ipv6/addrconf.c:3669 notifier_call_chain+0xb5/0x200 kernel/notifier.c:87 call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:1945 call_netdevice_notifiers_extack net/core/dev.c:1983 [inline] call_netdevice_notifiers net/core/dev.c:1997 [inline] netdev_wait_allrefs_any net/core/dev.c:10250 [inline] netdev_run_todo+0xbc2/0x1100 net/core/dev.c:10364 tun_detach drivers/net/tun.c:704 [inline] tun_chr_close+0xe0/0x180 drivers/net/tun.c:3455 __fput+0x277/0x9d0 fs/file_table.c:320 task_work_run+0xdd/0x1a0 kernel/task_work.c:177 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xad5/0x29b0 kernel/exit.c:795 do_group_exit+0xd2/0x2f0 kernel/exit.c:925 __do_sys_exit_group kernel/exit.c:936 [inline] __se_sys_exit_group kernel/exit.c:934 [inline] __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:934 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7fae1a289279 Code: Unable to access opcode bytes at RIP 0x7fae1a28924f. RSP: 002b:00007fff1e3f1198 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007fff1e3f1340 RCX: 00007fae1a289279 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000043 RBP: 0000000000000000 R08: 0000000000000025 R09: 00007fff1e3f1340 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fae1a2e32ba R13: 000000000000001c R14: 0000000000000005 R15: 00007fff1e3f1380 Allocated by task 3639: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:437 [inline] ____kasan_kmalloc mm/kasan/common.c:516 [inline] ____kasan_kmalloc mm/kasan/common.c:475 [inline] __kasan_kmalloc+0xa9/0xd0 mm/kasan/common.c:525 kmalloc include/linux/slab.h:600 [inline] kzalloc include/linux/slab.h:733 [inline] fib6_net_init net/ipv6/ip6_fib.c:2376 [inline] fib6_net_init+0x1d7/0xa20 net/ipv6/ip6_fib.c:2351 ops_init+0xaf/0x470 net/core/net_namespace.c:135 setup_net+0x5d1/0xc50 net/core/net_namespace.c:326 copy_net_ns+0x318/0x760 net/core/net_namespace.c:472 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0xc1/0x1f0 kernel/nsproxy.c:227 ksys_unshare+0x445/0x920 kernel/fork.c:3183 __do_sys_unshare kernel/fork.c:3254 [inline] __se_sys_unshare kernel/fork.c:3252 [inline] __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3252 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Freed by task 8: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 kasan_set_track+0x21/0x30 mm/kasan/common.c:45 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370 ____kasan_slab_free mm/kasan/common.c:367 [inline] ____kasan_slab_free+0x166/0x1c0 mm/kasan/common.c:329 kasan_slab_free include/linux/kasan.h:200 [inline] slab_free_hook mm/slub.c:1754 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1780 slab_free mm/slub.c:3534 [inline] kfree+0xe2/0x580 mm/slub.c:4562 fib6_net_exit+0x1c9/0x280 net/ipv6/ip6_fib.c:2438 ops_exit_list+0xb0/0x170 net/core/net_namespace.c:163 cleanup_net+0x4ea/0xb00 net/core/net_namespace.c:595 process_one_work+0x991/0x1610 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 kernel/workqueue.c:2436 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 Last potentially related work creation: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 __kasan_record_aux_stack+0xbe/0xd0 mm/kasan/generic.c:348 call_rcu+0x99/0x790 kernel/rcu/tree.c:2793 netlink_release+0xeff/0x1db0 net/netlink/af_netlink.c:815 __sock_release+0xcd/0x280 net/socket.c:650 sock_close+0x18/0x20 net/socket.c:1365 __fput+0x277/0x9d0 fs/file_table.c:320 task_work_run+0xdd/0x1a0 kernel/task_work.c:177 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop kernel/entry/common.c:169 [inline] exit_to_user_mode_prepare+0x23c/0x250 kernel/entry/common.c:201 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline] syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:294 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd The buggy address belongs to the object at ffff888026e39000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 0 bytes inside of 2048-byte region [ffff888026e39000, ffff888026e39800) The buggy address belongs to the physical page: page:ffffea00009b8e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x26e38 head:ffffea00009b8e00 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 dead000000000100 dead000000000122 ffff888011842000 raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 10259706859, free_ts 0 prep_new_page mm/page_alloc.c:2532 [inline] get_page_from_freelist+0x109b/0x2ce0 mm/page_alloc.c:4283 __alloc_pages+0x1c7/0x510 mm/page_alloc.c:5515 alloc_page_interleave+0x1e/0x200 mm/mempolicy.c:2103 alloc_pages+0x22f/0x270 mm/mempolicy.c:2265 alloc_slab_page mm/slub.c:1824 [inline] allocate_slab+0x27e/0x3d0 mm/slub.c:1969 new_slab mm/slub.c:2029 [inline] ___slab_alloc+0x7f1/0xe10 mm/slub.c:3031 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3118 slab_alloc_node mm/slub.c:3209 [inline] __kmalloc_node_track_caller+0x2f2/0x380 mm/slub.c:4955 kmalloc_reserve net/core/skbuff.c:358 [inline] __alloc_skb+0xd9/0x2f0 net/core/skbuff.c:430 alloc_skb include/linux/skbuff.h:1258 [inline] nlmsg_new include/net/netlink.h:955 [inline] rtmsg_ifinfo_build_skb+0x72/0x1a0 net/core/rtnetlink.c:3902 rtmsg_ifinfo_event net/core/rtnetlink.c:3938 [inline] rtmsg_ifinfo_event net/core/rtnetlink.c:3929 [inline] rtmsg_ifinfo+0x83/0x120 net/core/rtnetlink.c:3947 register_netdevice+0x12f1/0x1680 net/core/dev.c:10117 register_netdev+0x2d/0x50 net/core/dev.c:10196 rose_proto_init+0x369/0x73f net/rose/af_rose.c:1545 do_one_initcall+0xfe/0x650 init/main.c:1296 do_initcall_level init/main.c:1369 [inline] do_initcalls init/main.c:1385 [inline] do_basic_setup init/main.c:1404 [inline] kernel_init_freeable+0x6b1/0x73a init/main.c:1623 page_owner free stack trace missing Memory state around the buggy address: ffff888026e38f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888026e38f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888026e39000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888026e39080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888026e39100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================