================================================================== BUG: KASAN: slab-use-after-free in scr_memcpyw include/linux/vt_buffer.h:38 [inline] BUG: KASAN: slab-use-after-free in fbcon_prepare_logo+0xa03/0xc70 drivers/video/fbdev/core/fbcon.c:630 Read of size 126 at addr ffff888079b80430 by task syz.0.4628/26839 CPU: 1 UID: 0 PID: 26839 Comm: syz.0.4628 Not tainted 6.17.0-rc1-syzkaller-00224-g8d561baae505 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xcd/0x630 mm/kasan/report.c:482 kasan_report+0xe0/0x110 mm/kasan/report.c:595 check_region_inline mm/kasan/generic.c:183 [inline] kasan_check_range+0x100/0x1b0 mm/kasan/generic.c:189 __asan_memcpy+0x23/0x60 mm/kasan/shadow.c:105 scr_memcpyw include/linux/vt_buffer.h:38 [inline] fbcon_prepare_logo+0xa03/0xc70 drivers/video/fbdev/core/fbcon.c:630 fbcon_init+0xd77/0x1900 drivers/video/fbdev/core/fbcon.c:1163 visual_init+0x320/0x620 drivers/tty/vt/vt.c:1019 do_bind_con_driver.isra.0+0x57a/0xbf0 drivers/tty/vt/vt.c:3915 vt_bind drivers/tty/vt/vt.c:4071 [inline] store_bind+0x61d/0x760 drivers/tty/vt/vt.c:4143 dev_attr_store+0x58/0x80 drivers/base/core.c:2437 sysfs_kf_write+0xef/0x150 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x351/0x510 fs/kernfs/file.c:334 iter_file_splice_write+0x918/0x1270 fs/splice.c:738 do_splice_from fs/splice.c:935 [inline] direct_splice_actor+0x18f/0x6c0 fs/splice.c:1158 splice_direct_to_actor+0x345/0xa30 fs/splice.c:1102 do_splice_direct_actor fs/splice.c:1201 [inline] do_splice_direct+0x174/0x240 fs/splice.c:1227 do_sendfile+0xb06/0xe50 fs/read_write.c:1370 __do_sys_sendfile64 fs/read_write.c:1431 [inline] __se_sys_sendfile64 fs/read_write.c:1417 [inline] __x64_sys_sendfile64+0x1d8/0x220 fs/read_write.c:1417 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f676f58ebe9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f677040f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f676f7b5fa0 RCX: 00007f676f58ebe9 RDX: 0000000000000000 RSI: 0000000000000007 RDI: 0000000000000003 RBP: 00007f676f611e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f676f7b6038 R14: 00007f676f7b5fa0 R15: 00007ffdd0fc4a98 Allocated by task 26297: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:388 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:405 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4365 [inline] __kmalloc_node_track_caller_noprof+0x221/0x510 mm/slub.c:4384 kmemdup_noprof+0x29/0x60 mm/util.c:138 kmemdup_noprof include/linux/fortify-string.h:765 [inline] __devinet_sysctl_register+0xbc/0x360 net/ipv4/devinet.c:2666 devinet_sysctl_register net/ipv4/devinet.c:2718 [inline] devinet_sysctl_register+0x17b/0x200 net/ipv4/devinet.c:2708 inetdev_init+0x2b8/0x5a0 net/ipv4/devinet.c:291 inetdev_event+0xc5f/0x18a0 net/ipv4/devinet.c:1591 notifier_call_chain+0xbc/0x410 kernel/notifier.c:85 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2229 call_netdevice_notifiers_extack net/core/dev.c:2267 [inline] call_netdevice_notifiers net/core/dev.c:2281 [inline] register_netdevice+0x182e/0x2270 net/core/dev.c:11232 register_netdev+0x34/0x50 net/core/dev.c:11310 loopback_net_init+0x7a/0x170 drivers/net/loopback.c:218 ops_init+0x1df/0x5f0 net/core/net_namespace.c:136 setup_net+0x10f/0x380 net/core/net_namespace.c:438 copy_net_ns+0x2a6/0x5f0 net/core/net_namespace.c:570 create_new_namespaces+0x3ea/0xa90 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0xc0/0x1f0 kernel/nsproxy.c:218 ksys_unshare+0x45b/0xa40 kernel/fork.c:3127 __do_sys_unshare kernel/fork.c:3198 [inline] __se_sys_unshare kernel/fork.c:3196 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:3196 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 21052: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:243 [inline] __kasan_slab_free+0x60/0x70 mm/kasan/common.c:275 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2417 [inline] slab_free mm/slub.c:4680 [inline] kfree+0x2b4/0x4d0 mm/slub.c:4879 __devinet_sysctl_unregister net/ipv4/devinet.c:2702 [inline] devinet_sysctl_unregister net/ipv4/devinet.c:2729 [inline] inetdev_destroy net/ipv4/devinet.c:334 [inline] inetdev_event+0xeb4/0x18a0 net/ipv4/devinet.c:1656 notifier_call_chain+0xbc/0x410 kernel/notifier.c:85 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2229 call_netdevice_notifiers_extack net/core/dev.c:2267 [inline] call_netdevice_notifiers net/core/dev.c:2281 [inline] unregister_netdevice_many_notify+0xf76/0x24c0 net/core/dev.c:12154 unregister_netdevice_many net/core/dev.c:12217 [inline] default_device_exit_batch+0x853/0xaf0 net/core/dev.c:12721 ops_exit_list net/core/net_namespace.c:204 [inline] ops_undo_list+0x363/0xab0 net/core/net_namespace.c:251 cleanup_net+0x408/0x890 net/core/net_namespace.c:682 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:463 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 The buggy address belongs to the object at ffff888079b80000 which belongs to the cache kmalloc-cg-2k of size 2048 The buggy address is located 1072 bytes inside of freed 2048-byte region [ffff888079b80000, ffff888079b80800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x79b80 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 memcg:ffff888028ccf581 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88801b84b3c0 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000080008 00000000f5000000 ffff888028ccf581 head: 00fff00000000040 ffff88801b84b3c0 dead000000000100 dead000000000122 head: 0000000000000000 0000000000080008 00000000f5000000 ffff888028ccf581 head: 00fff00000000003 ffffea0001e6e001 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008 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 5856, tgid 5856 (syz-executor), ts 68904212043, free_ts 68858035412 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1851 prep_new_page mm/page_alloc.c:1859 [inline] get_page_from_freelist+0x132b/0x38e0 mm/page_alloc.c:3858 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:5148 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:2487 [inline] allocate_slab mm/slub.c:2655 [inline] new_slab+0x247/0x330 mm/slub.c:2709 ___slab_alloc+0xcf2/0x1740 mm/slub.c:3891 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3981 __slab_alloc_node mm/slub.c:4056 [inline] slab_alloc_node mm/slub.c:4217 [inline] __do_kmalloc_node mm/slub.c:4364 [inline] __kmalloc_node_track_caller_noprof+0x2ee/0x510 mm/slub.c:4384 kmemdup_noprof+0x29/0x60 mm/util.c:138 kmemdup_noprof include/linux/fortify-string.h:765 [inline] neigh_sysctl_register+0xb2/0x670 net/core/neighbour.c:3826 devinet_sysctl_register+0xb6/0x200 net/ipv4/devinet.c:2715 inetdev_init+0x2b8/0x5a0 net/ipv4/devinet.c:291 inetdev_event+0xc5f/0x18a0 net/ipv4/devinet.c:1591 notifier_call_chain+0xbc/0x410 kernel/notifier.c:85 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2229 call_netdevice_notifiers_extack net/core/dev.c:2267 [inline] call_netdevice_notifiers net/core/dev.c:2281 [inline] register_netdevice+0x182e/0x2270 net/core/dev.c:11232 page last free pid 5858 tgid 5858 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1395 [inline] __free_frozen_pages+0x7d5/0x10f0 mm/page_alloc.c:2895 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4d/0x120 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:340 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4180 [inline] slab_alloc_node mm/slub.c:4229 [inline] __kmalloc_cache_noprof+0x1f1/0x3e0 mm/slub.c:4391 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] ref_tracker_alloc+0x18e/0x5b0 lib/ref_tracker.c:271 __netdev_tracker_alloc include/linux/netdevice.h:4349 [inline] netdev_hold include/linux/netdevice.h:4378 [inline] netdev_hold include/linux/netdevice.h:4373 [inline] netdev_queue_add_kobject net/core/net-sysfs.c:1992 [inline] netdev_queue_update_kobjects+0x2db/0x720 net/core/net-sysfs.c:2054 register_queue_kobjects net/core/net-sysfs.c:2117 [inline] netdev_register_kobject+0x2b3/0x3d0 net/core/net-sysfs.c:2360 register_netdevice+0x13dc/0x2270 net/core/dev.c:11194 veth_newlink+0x30f/0xa00 drivers/net/veth.c:1855 rtnl_newlink_create net/core/rtnetlink.c:3825 [inline] __rtnl_newlink net/core/rtnetlink.c:3942 [inline] rtnl_newlink+0xc45/0x2000 net/core/rtnetlink.c:4057 rtnetlink_rcv_msg+0x95b/0xe90 net/core/rtnetlink.c:6946 netlink_rcv_skb+0x155/0x420 net/netlink/af_netlink.c:2552 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:714 [inline] __sock_sendmsg net/socket.c:729 [inline] __sys_sendto+0x4a3/0x520 net/socket.c:2228 Memory state around the buggy address: ffff888079b80300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888079b80380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888079b80400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888079b80480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888079b80500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================