================================================================== BUG: KASAN: use-after-free in __write_once_size include/linux/compiler.h:295 [inline] BUG: KASAN: use-after-free in __hlist_del include/linux/list.h:789 [inline] BUG: KASAN: use-after-free in detach_timer kernel/time/timer.c:824 [inline] BUG: KASAN: use-after-free in detach_if_pending+0x160/0x360 kernel/time/timer.c:841 Write of size 8 at addr ffff8881c46a71c0 by task syz-executor.2/26289 CPU: 1 PID: 26289 Comm: syz-executor.2 Tainted: G W 5.4.268-syzkaller-00012-gd0d34dcb02cc #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1d8/0x241 lib/dump_stack.c:118 print_address_description+0x8c/0x600 mm/kasan/report.c:384 __kasan_report+0xf3/0x120 mm/kasan/report.c:516 kasan_report+0x30/0x60 mm/kasan/common.c:653 __write_once_size include/linux/compiler.h:295 [inline] __hlist_del include/linux/list.h:789 [inline] detach_timer kernel/time/timer.c:824 [inline] detach_if_pending+0x160/0x360 kernel/time/timer.c:841 try_to_del_timer_sync kernel/time/timer.c:1238 [inline] del_timer_sync+0x13c/0x230 kernel/time/timer.c:1379 tun_flow_uninit+0x2c/0x280 drivers/net/tun.c:1451 tun_free_netdev+0x77/0x190 drivers/net/tun.c:2401 netdev_run_todo+0xb7f/0xdf0 net/core/dev.c:9458 tun_detach drivers/net/tun.c:765 [inline] tun_chr_close+0xc1/0x130 drivers/net/tun.c:3557 __fput+0x262/0x680 fs/file_table.c:281 task_work_run+0x140/0x170 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xcaf/0x2bc0 kernel/exit.c:859 do_group_exit+0x138/0x300 kernel/exit.c:982 get_signal+0xdb1/0x1440 kernel/signal.c:2735 do_signal+0xb0/0x11f0 arch/x86/kernel/signal.c:809 exit_to_usermode_loop+0xc0/0x1a0 arch/x86/entry/common.c:159 prepare_exit_to_usermode+0x199/0x200 arch/x86/entry/common.c:194 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 Allocated by task 17: save_stack mm/kasan/common.c:70 [inline] set_track mm/kasan/common.c:78 [inline] __kasan_kmalloc+0x171/0x210 mm/kasan/common.c:529 slab_post_alloc_hook mm/slab.h:584 [inline] slab_alloc_node mm/slub.c:2829 [inline] slab_alloc mm/slub.c:2837 [inline] __kmalloc_track_caller+0x100/0x2b0 mm/slub.c:4449 __kmalloc_reserve net/core/skbuff.c:142 [inline] __alloc_skb+0xb4/0x4d0 net/core/skbuff.c:210 alloc_skb include/linux/skbuff.h:1080 [inline] nlmsg_new include/net/netlink.h:888 [inline] fdb_notify+0x74/0x120 net/bridge/br_fdb.c:701 br_handle_frame_finish+0x1ee/0x1260 net/bridge/br_input.c:98 nf_hook_bridge_pre net/bridge/br_input.c:254 [inline] br_handle_frame+0x3da/0x8b0 net/bridge/br_input.c:355 __netif_receive_skb_core+0x11bc/0x37e0 net/core/dev.c:4866 __netif_receive_skb_one_core net/core/dev.c:4970 [inline] __netif_receive_skb+0x11c/0x530 net/core/dev.c:5086 process_backlog+0x34f/0x680 net/core/dev.c:5921 napi_poll net/core/dev.c:6367 [inline] net_rx_action+0x53f/0x1160 net/core/dev.c:6435 __do_softirq+0x23b/0x6b7 kernel/softirq.c:292 Freed by task 17: save_stack mm/kasan/common.c:70 [inline] set_track mm/kasan/common.c:78 [inline] kasan_set_free_info mm/kasan/common.c:345 [inline] __kasan_slab_free+0x1b5/0x270 mm/kasan/common.c:487 slab_free_hook mm/slub.c:1455 [inline] slab_free_freelist_hook mm/slub.c:1494 [inline] slab_free mm/slub.c:3080 [inline] kfree+0x123/0x370 mm/slub.c:4071 skb_release_all net/core/skbuff.c:675 [inline] __kfree_skb net/core/skbuff.c:689 [inline] consume_skb+0xa5/0x2a0 net/core/skbuff.c:849 netlink_broadcast_filtered+0x115f/0x1280 net/netlink/af_netlink.c:1531 netlink_broadcast net/netlink/af_netlink.c:1553 [inline] nlmsg_multicast include/net/netlink.h:968 [inline] nlmsg_notify+0xf7/0x1b0 net/netlink/af_netlink.c:2524 br_handle_frame_finish+0x1ee/0x1260 net/bridge/br_input.c:98 nf_hook_bridge_pre net/bridge/br_input.c:254 [inline] br_handle_frame+0x3da/0x8b0 net/bridge/br_input.c:355 __netif_receive_skb_core+0x11bc/0x37e0 net/core/dev.c:4866 __netif_receive_skb_one_core net/core/dev.c:4970 [inline] __netif_receive_skb+0x11c/0x530 net/core/dev.c:5086 process_backlog+0x34f/0x680 net/core/dev.c:5921 napi_poll net/core/dev.c:6367 [inline] net_rx_action+0x53f/0x1160 net/core/dev.c:6435 __do_softirq+0x23b/0x6b7 kernel/softirq.c:292 The buggy address belongs to the object at ffff8881c46a7000 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 448 bytes inside of 512-byte region [ffff8881c46a7000, ffff8881c46a7200) The buggy address belongs to the page: page:ffffea000711a900 refcount:1 mapcount:0 mapping:ffff8881f5c02500 index:0x0 compound_mapcount: 0 flags: 0x8000000000010200(slab|head) raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f5c02500 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL) set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook mm/page_alloc.c:2165 [inline] prep_new_page+0x18f/0x370 mm/page_alloc.c:2171 get_page_from_freelist+0x2d13/0x2d90 mm/page_alloc.c:3794 __alloc_pages_nodemask+0x393/0x840 mm/page_alloc.c:4891 alloc_slab_page+0x39/0x3c0 mm/slub.c:343 allocate_slab mm/slub.c:1683 [inline] new_slab+0x97/0x440 mm/slub.c:1749 new_slab_objects mm/slub.c:2505 [inline] ___slab_alloc+0x2fe/0x490 mm/slub.c:2667 __slab_alloc+0x62/0xa0 mm/slub.c:2707 slab_alloc_node mm/slub.c:2792 [inline] slab_alloc mm/slub.c:2837 [inline] __kmalloc+0x19b/0x2e0 mm/slub.c:3909 kmalloc include/linux/slab.h:561 [inline] kzalloc include/linux/slab.h:690 [inline] new_dir fs/proc/proc_sysctl.c:973 [inline] get_subdir fs/proc/proc_sysctl.c:1018 [inline] __register_sysctl_table+0x983/0x11d0 fs/proc/proc_sysctl.c:1361 neigh_sysctl_register+0x454/0x530 net/core/neighbour.c:3713 addrconf_sysctl_register+0xac/0x180 net/ipv6/addrconf.c:6989 ipv6_add_dev+0xb34/0x10a0 net/ipv6/addrconf.c:444 addrconf_notify+0x59b/0xe50 net/ipv6/addrconf.c:3539 notifier_call_chain kernel/notifier.c:98 [inline] __raw_notifier_call_chain kernel/notifier.c:399 [inline] raw_notifier_call_chain+0x95/0x110 kernel/notifier.c:406 call_netdevice_notifiers_info net/core/dev.c:1670 [inline] call_netdevice_notifiers_extack net/core/dev.c:1682 [inline] call_netdevice_notifiers net/core/dev.c:1696 [inline] register_netdevice+0xeef/0x12a0 net/core/dev.c:9221 tun_set_iff+0x7f7/0xdc0 drivers/net/tun.c:2916 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1176 [inline] free_pcp_prepare mm/page_alloc.c:1233 [inline] free_unref_page_prepare+0x297/0x380 mm/page_alloc.c:3085 free_unref_page mm/page_alloc.c:3134 [inline] free_the_page mm/page_alloc.c:4951 [inline] __free_pages mm/page_alloc.c:4959 [inline] free_pages+0x114/0x1b0 mm/page_alloc.c:4967 tlb_batch_list_free mm/mmu_gather.c:61 [inline] tlb_finish_mmu+0x249/0x320 mm/mmu_gather.c:280 exit_mmap+0x2dc/0x520 mm/mmap.c:3188 __mmput+0x8e/0x2c0 kernel/fork.c:1101 exit_mm kernel/exit.c:536 [inline] do_exit+0xc08/0x2bc0 kernel/exit.c:846 do_group_exit+0x138/0x300 kernel/exit.c:982 get_signal+0xdb1/0x1440 kernel/signal.c:2735 do_signal+0xb0/0x11f0 arch/x86/kernel/signal.c:809 exit_to_usermode_loop+0xc0/0x1a0 arch/x86/entry/common.c:159 prepare_exit_to_usermode+0x199/0x200 arch/x86/entry/common.c:194 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 Memory state around the buggy address: ffff8881c46a7080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881c46a7100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881c46a7180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881c46a7200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8881c46a7280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc 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