================================================================== 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 256 at addr ffff88805976a3c0 by task syz.1.1685/13411 CPU: 0 UID: 0 PID: 13411 Comm: syz.1.1685 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+0xa24/0x12e0 fs/splice.c:738 do_splice_from fs/splice.c:938 [inline] direct_splice_actor+0x192/0x6c0 fs/splice.c:1161 splice_direct_to_actor+0x345/0xa30 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: 0033:0x7ff54d78f6c9 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:00007ff54e645038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007ff54d9e6270 RCX: 00007ff54d78f6c9 RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000003 RBP: 00007ff54d811f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff54d9e6308 R14: 00007ff54d9e6270 R15: 00007ffff3b25d18 Allocated by task 13118: kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_save_track+0x14/0x30 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:400 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:417 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] kobject_uevent_env+0x265/0x1870 lib/kobject_uevent.c:540 netdev_queue_add_kobject net/core/net-sysfs.c:2013 [inline] netdev_queue_update_kobjects+0x1a7/0x720 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 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:1147 ops_init+0x1e2/0x5f0 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 13118: 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:2539 [inline] slab_free mm/slub.c:6634 [inline] kfree+0x2b8/0x6d0 mm/slub.c:6841 kobject_uevent_env+0x2e5/0x1870 lib/kobject_uevent.c:640 netdev_queue_add_kobject net/core/net-sysfs.c:2013 [inline] netdev_queue_update_kobjects+0x1a7/0x720 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 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:1147 ops_init+0x1e2/0x5f0 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 The buggy address belongs to the object at ffff88805976a000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 960 bytes inside of freed 4096-byte region [ffff88805976a000, ffff88805976b000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x59768 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 anon flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88813ffa7140 0000000000000000 dead000000000001 raw: 0000000000000000 0000000000040004 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88813ffa7140 0000000000000000 dead000000000001 head: 0000000000000000 0000000000040004 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea000165da01 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 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 11778, tgid 11778 (kworker/u8:17), ts 421605268807, free_ts 421501588834 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:3055 [inline] allocate_slab mm/slub.c:3228 [inline] new_slab+0x24a/0x360 mm/slub.c:3282 ___slab_alloc+0xd79/0x1a50 mm/slub.c:4651 __slab_alloc.constprop.0+0x63/0x110 mm/slub.c:4774 __slab_alloc_node mm/slub.c:4850 [inline] slab_alloc_node mm/slub.c:5272 [inline] __do_kmalloc_node mm/slub.c:5645 [inline] __kmalloc_noprof+0x501/0x880 mm/slub.c:5658 kmalloc_noprof include/linux/slab.h:961 [inline] tomoyo_realpath_from_path+0xc2/0x6e0 security/tomoyo/realpath.c:251 tomoyo_scan_exec_realpath security/tomoyo/condition.c:243 [inline] tomoyo_condition+0xbcd/0x3bd0 security/tomoyo/condition.c:827 tomoyo_check_acl+0x1b7/0x410 security/tomoyo/domain.c:177 tomoyo_execute_permission+0x176/0x4b0 security/tomoyo/file.c:615 tomoyo_find_next_domain+0x38d/0x20b0 security/tomoyo/domain.c:762 tomoyo_bprm_check_security security/tomoyo/tomoyo.c:102 [inline] tomoyo_bprm_check_security+0x12e/0x1d0 security/tomoyo/tomoyo.c:92 security_bprm_check+0x1b9/0x1e0 security/security.c:1341 search_binary_handler fs/exec.c:1660 [inline] exec_binprm fs/exec.c:1702 [inline] bprm_execve fs/exec.c:1754 [inline] bprm_execve+0x81a/0x1640 fs/exec.c:1730 page last free pid 11770 tgid 11770 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 discard_slab mm/slub.c:3326 [inline] __put_partials+0x130/0x170 mm/slub.c:3872 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:352 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4974 [inline] slab_alloc_node mm/slub.c:5284 [inline] kmem_cache_alloc_noprof+0x250/0x6e0 mm/slub.c:5291 new_handle fs/jbd2/transaction.c:457 [inline] jbd2__journal_start+0x193/0x6a0 fs/jbd2/transaction.c:484 __ext4_journal_start_sb+0x195/0x690 fs/ext4/ext4_jbd2.c:115 __ext4_journal_start fs/ext4/ext4_jbd2.h:242 [inline] ext4_dirty_inode+0xa1/0x130 fs/ext4/inode.c:6514 __mark_inode_dirty+0x1ee/0xe40 fs/fs-writeback.c:2566 generic_update_time+0xcf/0xf0 fs/inode.c:2105 inode_update_time fs/inode.c:2118 [inline] __file_update_time fs/inode.c:2345 [inline] file_update_time+0x17d/0x1c0 fs/inode.c:2375 ext4_page_mkwrite+0x33d/0x1880 fs/ext4/inode.c:6683 do_page_mkwrite+0x174/0x380 mm/memory.c:3488 do_shared_fault mm/memory.c:5774 [inline] do_fault mm/memory.c:5836 [inline] do_pte_missing+0x29d/0x3ba0 mm/memory.c:4361 handle_pte_fault mm/memory.c:6177 [inline] __handle_mm_fault+0x1556/0x2aa0 mm/memory.c:6318 Memory state around the buggy address: ffff88805976a280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88805976a300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88805976a380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88805976a400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88805976a480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================