================================================================== 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:623 Read of size 8 at addr ffff88805dfe8340 by task syz.1.2517/18141 CPU: 0 UID: 0 PID: 18141 Comm: syz.1.2517 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 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:194 [inline] kasan_check_range+0x100/0x1b0 mm/kasan/generic.c:200 __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:623 fbcon_init+0xd77/0x1900 drivers/video/fbdev/core/fbcon.c:1156 visual_init+0x320/0x620 drivers/tty/vt/vt.c:1020 do_bind_con_driver.isra.0+0x57a/0xbf0 drivers/tty/vt/vt.c:3960 vt_bind drivers/tty/vt/vt.c:4116 [inline] store_bind+0x61d/0x760 drivers/tty/vt/vt.c:4188 dev_attr_store+0x58/0x80 drivers/base/core.c:2437 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:142 kernfs_fop_write_iter+0x3af/0x570 fs/kernfs/file.c:352 iter_file_splice_write+0xa21/0x12e0 fs/splice.c:738 do_splice_from fs/splice.c:938 [inline] direct_splice_actor+0x18f/0x6c0 fs/splice.c:1161 splice_direct_to_actor+0x342/0xa30 fs/splice.c:1105 do_splice_direct_actor fs/splice.c:1204 [inline] do_splice_direct+0x174/0x240 fs/splice.c:1230 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/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7feffa78eec9 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:00007feffb6a4038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007feffa9e6180 RCX: 00007feffa78eec9 RDX: 0000000000000000 RSI: 0000000000000008 RDI: 0000000000000003 RBP: 00007feffa811f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000 R13: 00007feffa9e6218 R14: 00007feffa9e6180 R15: 00007ffc3b4e7db8 Allocated by task 17995: kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_save_track+0x14/0x30 mm/kasan/common.c:77 unpoison_slab_object mm/kasan/common.c:342 [inline] __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:368 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4947 [inline] slab_alloc_node mm/slub.c:5246 [inline] kmem_cache_alloc_noprof+0x250/0x6e0 mm/slub.c:5253 __kernfs_new_node+0xd2/0x8e0 fs/kernfs/dir.c:637 kernfs_new_node+0x13c/0x1e0 fs/kernfs/dir.c:713 kernfs_create_dir_ns+0x4c/0x1a0 fs/kernfs/dir.c:1083 internal_create_group+0x34d/0xf30 fs/sysfs/group.c:170 internal_create_groups+0x9d/0x150 fs/sysfs/group.c:223 device_add_groups drivers/base/core.c:2836 [inline] device_add_attrs drivers/base/core.c:2911 [inline] device_add+0xf30/0x1aa0 drivers/base/core.c:3643 netdev_register_kobject+0x1a9/0x3d0 net/core/net-sysfs.c:2358 register_netdevice+0x13dc/0x2270 net/core/dev.c:11294 __ip_tunnel_create+0x540/0x6e0 net/ipv4/ip_tunnel.c:268 ip_tunnel_init_net+0x22f/0x7d0 net/ipv4/ip_tunnel.c:1161 ops_init+0x1df/0x5f0 net/core/net_namespace.c:137 setup_net+0x100/0x390 net/core/net_namespace.c:445 copy_net_ns+0x2f8/0x690 net/core/net_namespace.c:580 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:3129 __do_sys_unshare kernel/fork.c:3200 [inline] __se_sys_unshare kernel/fork.c:3198 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:3198 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 15: kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_save_track+0x14/0x30 mm/kasan/common.c:77 __kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:587 kasan_save_free_info mm/kasan/kasan.h:406 [inline] poison_slab_object mm/kasan/common.c:252 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2515 [inline] slab_free mm/slub.c:6574 [inline] kmem_cache_free+0x2d4/0x6c0 mm/slub.c:6684 rcu_do_batch kernel/rcu/tree.c:2605 [inline] rcu_core+0x799/0x1530 kernel/rcu/tree.c:2861 handle_softirqs+0x219/0x8e0 kernel/softirq.c:622 run_ksoftirqd kernel/softirq.c:1063 [inline] run_ksoftirqd+0x3a/0x60 kernel/softirq.c:1055 smpboot_thread_fn+0x3f4/0xae0 kernel/smpboot.c:160 kthread+0x3c2/0x780 kernel/kthread.c:463 ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Last potentially related work creation: kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:559 __call_rcu_common.constprop.0+0xa5/0xa10 kernel/rcu/tree.c:3123 kernfs_put.part.0+0x162/0x640 fs/kernfs/dir.c:591 kernfs_put+0x4e/0x60 fs/kernfs/dir.c:602 sysfs_remove_group+0xc6/0x180 fs/sysfs/group.c:326 sysfs_remove_groups fs/sysfs/group.c:346 [inline] sysfs_remove_groups+0x60/0xa0 fs/sysfs/group.c:338 device_remove_groups drivers/base/core.c:2843 [inline] device_remove_attrs+0x192/0x290 drivers/base/core.c:2973 device_del+0x38e/0x9f0 drivers/base/core.c:3877 unregister_netdevice_many_notify+0x14f0/0x24c0 net/core/dev.c:12289 ops_exit_rtnl_list net/core/net_namespace.c:187 [inline] ops_undo_list+0x8fc/0xab0 net/core/net_namespace.c:248 setup_net+0x1e2/0x390 net/core/net_namespace.c:461 copy_net_ns+0x2f8/0x690 net/core/net_namespace.c:580 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:3129 __do_sys_unshare kernel/fork.c:3200 [inline] __se_sys_unshare kernel/fork.c:3198 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:3198 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88805dfe82d0 which belongs to the cache kernfs_node_cache of size 176 The buggy address is located 112 bytes inside of freed 176-byte region [ffff88805dfe82d0, ffff88805dfe8380) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5dfe8 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff88801bec3dc0 ffffea000177e700 dead000000000008 raw: 0000000000000000 0000000000110011 00000000f5000000 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 5842, tgid 5842 (syz-executor), ts 106558013406, free_ts 36449727983 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1850 prep_new_page mm/page_alloc.c:1858 [inline] get_page_from_freelist+0x10a3/0x3a30 mm/page_alloc.c:3884 __alloc_frozen_pages_noprof+0x25f/0x2470 mm/page_alloc.c:5183 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:3031 [inline] allocate_slab mm/slub.c:3204 [inline] new_slab+0x24a/0x360 mm/slub.c:3258 ___slab_alloc+0xdc4/0x1ae0 mm/slub.c:4628 __slab_alloc.constprop.0+0x63/0x110 mm/slub.c:4747 __slab_alloc_node mm/slub.c:4823 [inline] slab_alloc_node mm/slub.c:5234 [inline] kmem_cache_alloc_noprof+0x43f/0x6e0 mm/slub.c:5253 __kernfs_new_node+0xd2/0x8e0 fs/kernfs/dir.c:637 kernfs_new_node+0x13c/0x1e0 fs/kernfs/dir.c:713 __kernfs_create_file+0x53/0x350 fs/kernfs/file.c:1057 sysfs_add_file_mode_ns+0x207/0x3c0 fs/sysfs/file.c:313 create_files fs/sysfs/group.c:76 [inline] internal_create_group+0x578/0xf30 fs/sysfs/group.c:183 internal_create_groups+0x9d/0x150 fs/sysfs/group.c:223 netdev_queue_add_kobject net/core/net-sysfs.c:2003 [inline] netdev_queue_update_kobjects+0x115/0x720 net/core/net-sysfs.c:2056 register_queue_kobjects net/core/net-sysfs.c:2119 [inline] netdev_register_kobject+0x2b3/0x3d0 net/core/net-sysfs.c:2362 page last free pid 1 tgid 1 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1394 [inline] __free_frozen_pages+0x7df/0x1160 mm/page_alloc.c:2906 __free_pages mm/page_alloc.c:5302 [inline] free_contig_range+0x183/0x4b0 mm/page_alloc.c:7146 destroy_args+0xb69/0x12e0 mm/debug_vm_pgtable.c:958 debug_vm_pgtable+0x1a32/0x3640 mm/debug_vm_pgtable.c:1345 do_one_initcall+0x120/0x6e0 init/main.c:1283 do_initcall_level init/main.c:1345 [inline] do_initcalls init/main.c:1361 [inline] do_basic_setup init/main.c:1380 [inline] kernel_init_freeable+0x5c2/0x910 init/main.c:1593 kernel_init+0x1c/0x2b0 init/main.c:1483 ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff88805dfe8200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88805dfe8280: 00 00 fc fc fc fc fc fc fc fc fa fb fb fb fb fb >ffff88805dfe8300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88805dfe8380: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ffff88805dfe8400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc 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