================================================================== BUG: KASAN: use-after-free in __fib6_clean_all+0x296/0x2a0 net/ipv6/ip6_fib.c:2255 Read of size 8 at addr ffff888051b36000 by task syz-executor.5/3623 CPU: 1 PID: 3623 Comm: syz-executor.5 Not tainted 5.17.0-rc7-syzkaller-02443-gd96657dc9238 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description.constprop.0.cold+0x8d/0x336 mm/kasan/report.c:255 __kasan_report mm/kasan/report.c:442 [inline] kasan_report.cold+0x83/0xdf mm/kasan/report.c:459 __fib6_clean_all+0x296/0x2a0 net/ipv6/ip6_fib.c:2255 rt6_sync_down_dev net/ipv6/route.c:4894 [inline] rt6_disable_ip+0x7b7/0x9a0 net/ipv6/route.c:4899 addrconf_ifdown.isra.0+0xf6/0x16b0 net/ipv6/addrconf.c:3738 addrconf_notify+0xeb/0x1ba0 net/ipv6/addrconf.c:3662 notifier_call_chain+0xb5/0x200 kernel/notifier.c:84 call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:1938 call_netdevice_notifiers_extack net/core/dev.c:1976 [inline] call_netdevice_notifiers net/core/dev.c:1990 [inline] netdev_wait_allrefs_any net/core/dev.c:10117 [inline] netdev_run_todo+0xb90/0x10b0 net/core/dev.c:10229 tun_detach drivers/net/tun.c:696 [inline] tun_chr_close+0xe0/0x180 drivers/net/tun.c:3445 __fput+0x286/0x9f0 fs/file_table.c:317 task_work_run+0xdd/0x1a0 kernel/task_work.c:164 exit_task_work include/linux/task_work.h:32 [inline] do_exit+0xb29/0x2a30 kernel/exit.c:806 do_group_exit+0xd2/0x2f0 kernel/exit.c:935 __do_sys_exit_group kernel/exit.c:946 [inline] __se_sys_exit_group kernel/exit.c:944 [inline] __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:944 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+0x44/0xae RIP: 0033:0x7fd618b90049 Code: Unable to access opcode bytes at RIP 0x7fd618b9001f. RSP: 002b:00007ffc1fc03498 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007ffc1fc03640 RCX: 00007fd618b90049 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000043 RBP: 0000000000000000 R08: 0000000000000025 R09: 00007ffc1fc03640 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fd618bea05e R13: 000000000000001c R14: 0000000000000003 R15: 00007ffc1fc03680 Allocated by task 3623: 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:436 [inline] ____kasan_kmalloc mm/kasan/common.c:515 [inline] ____kasan_kmalloc mm/kasan/common.c:474 [inline] __kasan_kmalloc+0xa9/0xd0 mm/kasan/common.c:524 kmalloc include/linux/slab.h:581 [inline] kzalloc include/linux/slab.h:714 [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:134 setup_net+0x5d1/0xc50 net/core/net_namespace.c:325 copy_net_ns+0x318/0x760 net/core/net_namespace.c:471 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0xc1/0x1f0 kernel/nsproxy.c:226 ksys_unshare+0x445/0x920 kernel/fork.c:3058 __do_sys_unshare kernel/fork.c:3129 [inline] __se_sys_unshare kernel/fork.c:3127 [inline] __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3127 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+0x44/0xae Freed by task 4729: 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:366 [inline] ____kasan_slab_free+0x126/0x160 mm/kasan/common.c:328 kasan_slab_free include/linux/kasan.h:236 [inline] slab_free_hook mm/slub.c:1728 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1754 slab_free mm/slub.c:3509 [inline] kfree+0xd0/0x390 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:162 cleanup_net+0x4ea/0xb00 net/core/net_namespace.c:594 process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307 worker_thread+0x657/0x1110 kernel/workqueue.c:2454 kthread+0x2e9/0x3a0 kernel/kthread.c:377 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 The buggy address belongs to the object at ffff888051b36000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 0 bytes inside of 2048-byte region [ffff888051b36000, ffff888051b36800) The buggy address belongs to the page: page:ffffea000146cc00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x51b30 head:ffffea000146cc00 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 0000000000000000 dead000000000001 ffff888010c42000 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 3637, ts 119026551477, free_ts 11719235242 prep_new_page mm/page_alloc.c:2434 [inline] get_page_from_freelist+0xa72/0x2f50 mm/page_alloc.c:4165 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5389 alloc_pages+0x1aa/0x310 mm/mempolicy.c:2271 alloc_slab_page mm/slub.c:1799 [inline] allocate_slab+0x27f/0x3c0 mm/slub.c:1944 new_slab mm/slub.c:2004 [inline] ___slab_alloc+0xbe1/0x12b0 mm/slub.c:3018 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3105 slab_alloc_node mm/slub.c:3196 [inline] __kmalloc_node_track_caller+0x339/0x470 mm/slub.c:4957 kmalloc_reserve net/core/skbuff.c:354 [inline] __alloc_skb+0xde/0x340 net/core/skbuff.c:426 alloc_skb include/linux/skbuff.h:1300 [inline] alloc_skb_with_frags+0x93/0x620 net/core/skbuff.c:5988 sock_alloc_send_pskb+0x793/0x920 net/core/sock.c:2600 mld_newpack.isra.0+0x1be/0x750 net/ipv6/mcast.c:1746 add_grhead+0x283/0x360 net/ipv6/mcast.c:1849 add_grec+0x106a/0x1530 net/ipv6/mcast.c:1987 mld_send_initial_cr.part.0+0xf6/0x230 net/ipv6/mcast.c:2234 mld_send_initial_cr net/ipv6/mcast.c:1232 [inline] mld_dad_work+0x1d3/0x690 net/ipv6/mcast.c:2260 process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1352 [inline] free_pcp_prepare+0x374/0x870 mm/page_alloc.c:1404 free_unref_page_prepare mm/page_alloc.c:3325 [inline] free_unref_page+0x19/0x690 mm/page_alloc.c:3404 free_contig_range+0xa8/0xf0 mm/page_alloc.c:9335 destroy_args+0xa8/0x646 mm/debug_vm_pgtable.c:1018 debug_vm_pgtable+0x298e/0x2a20 mm/debug_vm_pgtable.c:1332 do_one_initcall+0x103/0x650 init/main.c:1302 do_initcall_level init/main.c:1375 [inline] do_initcalls init/main.c:1391 [inline] do_basic_setup init/main.c:1410 [inline] kernel_init_freeable+0x6b1/0x73a init/main.c:1615 kernel_init+0x1a/0x1d0 init/main.c:1504 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Memory state around the buggy address: ffff888051b35f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888051b35f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888051b36000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888051b36080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888051b36100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================