================================================================== BUG: KASAN: use-after-free in __fib6_clean_all+0x21d/0x8a0 Read of size 8 at addr ffff88807a9b9000 by task syz-executor.2/27800 CPU: 0 PID: 27800 Comm: syz-executor.2 Not tainted 5.19.0-rc2-syzkaller-00097-g48a23ec6ff2b #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+0x1e3/0x2cb lib/dump_stack.c:106 print_address_description+0x65/0x4b0 mm/kasan/report.c:313 print_report+0xf4/0x210 mm/kasan/report.c:429 kasan_report+0xfb/0x130 mm/kasan/report.c:491 __fib6_clean_all+0x21d/0x8a0 rt6_sync_down_dev net/ipv6/route.c:4887 [inline] rt6_disable_ip+0x14c/0x8e0 net/ipv6/route.c:4892 addrconf_ifdown+0x16b/0x1bc0 net/ipv6/addrconf.c:3750 addrconf_notify+0x403/0xf80 notifier_call_chain kernel/notifier.c:87 [inline] raw_notifier_call_chain+0xe7/0x170 kernel/notifier.c:455 call_netdevice_notifiers_info net/core/dev.c:1943 [inline] call_netdevice_notifiers_extack net/core/dev.c:1981 [inline] call_netdevice_notifiers net/core/dev.c:1995 [inline] netdev_wait_allrefs_any net/core/dev.c:10225 [inline] netdev_run_todo+0x8db/0x1070 net/core/dev.c:10337 tun_detach drivers/net/tun.c:695 [inline] tun_chr_close+0x11f/0x130 drivers/net/tun.c:3444 __fput+0x3b9/0x820 fs/file_table.c:317 task_work_run+0x146/0x1c0 kernel/task_work.c:177 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0x547/0x1ed0 kernel/exit.c:795 do_group_exit+0x23b/0x2f0 kernel/exit.c:925 get_signal+0x172f/0x1780 kernel/signal.c:2857 arch_do_signal_or_restart+0x8d/0x750 arch/x86/kernel/signal.c:869 exit_to_user_mode_loop+0x74/0x160 kernel/entry/common.c:166 exit_to_user_mode_prepare+0xad/0x110 kernel/entry/common.c:201 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline] syscall_exit_to_user_mode+0x2e/0x60 kernel/entry/common.c:294 ret_from_fork+0x15/0x30 RIP: 0033:0x7fb223e89109 Code: Unable to access opcode bytes at RIP 0x7fb223e890df. RSP: 002b:00007fb224f2a118 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: 0000000000000000 RBX: 00007fb223f9bf60 RCX: 00007fb223e89109 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007fb223ee305d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffd8c5f445f R14: 00007fb224f2a300 R15: 0000000000022000 Allocated by task 3627: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:436 [inline] ____kasan_kmalloc+0xdc/0x110 mm/kasan/common.c:515 kasan_kmalloc include/linux/kasan.h:234 [inline] kmem_cache_alloc_trace+0x94/0x310 mm/slub.c:3255 kmalloc include/linux/slab.h:600 [inline] kzalloc include/linux/slab.h:733 [inline] fib6_net_init+0x1a6/0x800 net/ipv6/ip6_fib.c:2376 ops_init+0x313/0x430 net/core/net_namespace.c:134 setup_net+0x4bb/0xc10 net/core/net_namespace.c:325 copy_net_ns+0x359/0x5b0 net/core/net_namespace.c:471 create_new_namespaces+0x4db/0x8e0 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0x11e/0x180 kernel/nsproxy.c:226 ksys_unshare+0x57f/0xb30 kernel/fork.c:3165 __do_sys_unshare kernel/fork.c:3236 [inline] __se_sys_unshare kernel/fork.c:3234 [inline] __x64_sys_unshare+0x34/0x40 kernel/fork.c:3234 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 The buggy address belongs to the object at ffff88807a9b9000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 0 bytes inside of 2048-byte region [ffff88807a9b9000, ffff88807a9b9800) The buggy address belongs to the physical page: page:ffffea0001ea6e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88807a9b9000 pfn:0x7a9b8 head:ffffea0001ea6e00 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 ffffea00009dc808 ffffea0001f93408 ffff888011c42000 raw: ffff88807a9b9000 0000000000080003 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 3627, tgid 3627 (syz-executor.2), ts 64145017966, free_ts 59650190692 prep_new_page mm/page_alloc.c:2456 [inline] get_page_from_freelist+0x72b/0x7a0 mm/page_alloc.c:4198 __alloc_pages+0x259/0x560 mm/page_alloc.c:5426 alloc_slab_page+0x70/0xf0 mm/slub.c:1797 allocate_slab+0x5e/0x520 mm/slub.c:1942 new_slab mm/slub.c:2002 [inline] ___slab_alloc+0x41e/0xcd0 mm/slub.c:3002 __slab_alloc mm/slub.c:3089 [inline] slab_alloc_node mm/slub.c:3180 [inline] slab_alloc mm/slub.c:3222 [inline] __kmalloc+0x2ba/0x370 mm/slub.c:4413 kmalloc include/linux/slab.h:605 [inline] sk_prot_alloc+0xde/0x200 net/core/sock.c:1975 sk_alloc+0x36/0x340 net/core/sock.c:2028 __netlink_create+0x68/0x220 net/netlink/af_netlink.c:647 __netlink_kernel_create+0x1cf/0x7b0 net/netlink/af_netlink.c:2045 netlink_kernel_create include/linux/netlink.h:62 [inline] xfrm_user_net_init+0x9e/0x150 net/xfrm/xfrm_user.c:3600 ops_init+0x313/0x430 net/core/net_namespace.c:134 setup_net+0x4bb/0xc10 net/core/net_namespace.c:325 copy_net_ns+0x359/0x5b0 net/core/net_namespace.c:471 create_new_namespaces+0x4db/0x8e0 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0x11e/0x180 kernel/nsproxy.c:226 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1371 [inline] free_pcp_prepare+0x812/0x900 mm/page_alloc.c:1421 free_unref_page_prepare mm/page_alloc.c:3343 [inline] free_unref_page+0x7d/0x390 mm/page_alloc.c:3438 free_slab mm/slub.c:2041 [inline] discard_slab mm/slub.c:2047 [inline] __unfreeze_partials+0x1ab/0x200 mm/slub.c:2521 put_cpu_partial+0x116/0x180 mm/slub.c:2597 do_slab_free mm/slub.c:3495 [inline] ___cache_free+0x118/0x1a0 mm/slub.c:3514 qlist_free_all+0x2b/0x70 mm/kasan/quarantine.c:187 kasan_quarantine_reduce+0x169/0x180 mm/kasan/quarantine.c:294 __kasan_slab_alloc+0x2f/0xe0 mm/kasan/common.c:446 kasan_slab_alloc include/linux/kasan.h:224 [inline] slab_post_alloc_hook mm/slab.h:750 [inline] slab_alloc_node mm/slub.c:3214 [inline] kmem_cache_alloc_node+0x1cd/0x340 mm/slub.c:3264 __alloc_skb+0xd5/0x660 net/core/skbuff.c:414 alloc_skb_fclone include/linux/skbuff.h:1476 [inline] tcp_stream_alloc_skb+0x67/0x480 net/ipv4/tcp.c:862 tcp_sendmsg_locked+0xd64/0x3fc0 net/ipv4/tcp.c:1297 tcp_sendmsg+0x2c/0x40 net/ipv4/tcp.c:1448 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg net/socket.c:734 [inline] sock_write_iter+0x3e7/0x560 net/socket.c:1108 call_write_iter include/linux/fs.h:2058 [inline] new_sync_write fs/read_write.c:504 [inline] vfs_write+0xa22/0xd40 fs/read_write.c:591 ksys_write+0x19b/0x2c0 fs/read_write.c:644 Memory state around the buggy address: ffff88807a9b8f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88807a9b8f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88807a9b9000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807a9b9080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807a9b9100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================