================================================================== BUG: KASAN: use-after-free in __fib6_clean_all+0x21d/0x8a0 Read of size 8 at addr ffff888147882000 by task syz-executor.4/12202 CPU: 0 PID: 12202 Comm: syz-executor.4 Not tainted 6.0.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022 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:317 print_report+0x108/0x220 mm/kasan/report.c:433 kasan_report+0xfb/0x130 mm/kasan/report.c:495 __fib6_clean_all+0x21d/0x8a0 rt6_sync_down_dev net/ipv6/route.c:4894 [inline] rt6_disable_ip+0x14c/0x960 net/ipv6/route.c:4899 addrconf_ifdown+0x16b/0x1bc0 net/ipv6/addrconf.c:3750 addrconf_notify+0x3be/0xfe0 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:1945 [inline] 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+0x8fb/0x1090 net/core/dev.c:10364 tun_detach drivers/net/tun.c:704 [inline] tun_chr_close+0x11f/0x130 drivers/net/tun.c:3455 __fput+0x3b9/0x820 fs/file_table.c:320 task_work_run+0x146/0x1c0 kernel/task_work.c:177 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0x55e/0x20a0 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 arch/x86/entry/entry_64.S:299 RIP: 0033:0x7f2240e8a669 Code: Unable to access opcode bytes at RIP 0x7f2240e8a63f. RSP: 002b:00007f2242083118 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: 0000000000000000 RBX: 00007f2240fabf80 RCX: 00007f2240e8a669 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f2240ee5560 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffe0790d8ff R14: 00007f2242083300 R15: 0000000000022000 Allocated by task 3621: 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:437 [inline] ____kasan_kmalloc+0xdc/0x110 mm/kasan/common.c:516 kasan_kmalloc include/linux/kasan.h:234 [inline] kmem_cache_alloc_trace+0x97/0x310 mm/slub.c:3289 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:135 setup_net+0x4bb/0xc10 net/core/net_namespace.c:326 copy_net_ns+0x359/0x5b0 net/core/net_namespace.c:472 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:3181 __do_sys_unshare kernel/fork.c:3252 [inline] __se_sys_unshare kernel/fork.c:3250 [inline] __x64_sys_unshare+0x34/0x40 kernel/fork.c:3250 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+0x63/0xcd Freed by task 20591: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4c/0x70 mm/kasan/common.c:45 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:370 ____kasan_slab_free+0xd8/0x120 mm/kasan/common.c:367 kasan_slab_free include/linux/kasan.h:200 [inline] slab_free_hook mm/slub.c:1759 [inline] slab_free_freelist_hook+0x12e/0x1a0 mm/slub.c:1785 slab_free mm/slub.c:3539 [inline] kfree+0xda/0x210 mm/slub.c:4567 fib6_net_exit+0x32d/0x370 net/ipv6/ip6_fib.c:2438 ops_exit_list net/core/net_namespace.c:163 [inline] cleanup_net+0x758/0xc50 net/core/net_namespace.c:595 process_one_work+0x81c/0xd10 kernel/workqueue.c:2289 worker_thread+0xb14/0x1330 kernel/workqueue.c:2436 kthread+0x266/0x300 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 The buggy address belongs to the object at ffff888147882000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 0 bytes inside of 2048-byte region [ffff888147882000, ffff888147882800) The buggy address belongs to the physical page: page:ffffea00051e2000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x147880 head:ffffea00051e2000 order:3 compound_mapcount:0 compound_pincount:0 flags: 0x57ff00000010200(slab|head|node=1|zone=2|lastcpupid=0x7ff) raw: 057ff00000010200 ffffea00051be200 dead000000000002 ffff888012042000 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 6233885021, free_ts 0 prep_new_page mm/page_alloc.c:2532 [inline] get_page_from_freelist+0x72b/0x7a0 mm/page_alloc.c:4283 __alloc_pages+0x259/0x560 mm/page_alloc.c:5515 alloc_page_interleave+0x22/0x1c0 mm/mempolicy.c:2103 alloc_slab_page+0x70/0xf0 mm/slub.c:1829 allocate_slab+0x5e/0x520 mm/slub.c:1974 new_slab mm/slub.c:2034 [inline] ___slab_alloc+0x42e/0xce0 mm/slub.c:3036 __slab_alloc mm/slub.c:3123 [inline] slab_alloc_node mm/slub.c:3214 [inline] kmem_cache_alloc_node_trace+0x29c/0x360 mm/slub.c:3312 kmalloc_node include/linux/slab.h:618 [inline] kzalloc_node include/linux/slab.h:744 [inline] __alloc_disk_node+0x5c/0x590 block/genhd.c:1343 __blk_mq_alloc_disk+0x11b/0x1e0 block/blk-mq.c:3942 nbd_dev_add+0x35d/0xa80 drivers/block/nbd.c:1781 nbd_init+0x21d/0x2ca drivers/block/nbd.c:2525 do_one_initcall+0xbd/0x2b0 init/main.c:1296 do_initcall_level+0x168/0x218 init/main.c:1369 do_initcalls+0x4b/0x8c init/main.c:1385 kernel_init_freeable+0x43a/0x5c3 init/main.c:1623 kernel_init+0x19/0x2b0 init/main.c:1512 page_owner free stack trace missing Memory state around the buggy address: ffff888147881f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888147881f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888147882000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888147882080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888147882100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================