================================================================== BUG: KASAN: slab-out-of-bounds in scr_memcpyw include/linux/vt_buffer.h:38 [inline] BUG: KASAN: slab-out-of-bounds in fbcon_prepare_logo+0xa03/0xc70 drivers/video/fbdev/core/fbcon.c:625 Read of size 256 at addr ffff8880751be380 by task syz.1.1492/13291 CPU: 1 UID: 0 PID: 13291 Comm: syz.1.1492 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 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:625 fbcon_init+0xd77/0x1900 drivers/video/fbdev/core/fbcon.c:1158 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: 0033:0x7f8965b8f7c9 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:00007f8966ade038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f8965de6090 RCX: 00007f8965b8f7c9 RDX: 0000000000000000 RSI: 0000000000000007 RDI: 0000000000000003 RBP: 00007f8965c13f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f8965de6128 R14: 00007f8965de6090 R15: 00007ffeec6faa68 Allocated by task 12292: 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:4978 [inline] slab_alloc_node mm/slub.c:5288 [inline] kmem_cache_alloc_node_noprof+0x28a/0x770 mm/slub.c:5340 kmalloc_reserve+0x18b/0x2c0 net/core/skbuff.c:579 __alloc_skb+0x166/0x380 net/core/skbuff.c:670 alloc_skb_fclone include/linux/skbuff.h:1433 [inline] tcp_stream_alloc_skb+0x34/0x560 net/ipv4/tcp.c:912 tso_fragment net/ipv4/tcp_output.c:2324 [inline] tcp_write_xmit+0x8af/0x86e0 net/ipv4/tcp_output.c:2985 __tcp_push_pending_frames+0xaf/0x390 net/ipv4/tcp_output.c:3182 tcp_send_fin+0x121/0x1050 net/ipv4/tcp_output.c:3800 __tcp_close+0xa46/0x1120 net/ipv4/tcp.c:3207 tcp_close+0x28/0x120 net/ipv4/tcp.c:3298 inet_release+0xed/0x200 net/ipv4/af_inet.c:437 __sock_release+0xb3/0x270 net/socket.c:662 sock_close+0x1c/0x30 net/socket.c:1455 __fput+0x402/0xb70 fs/file_table.c:468 task_work_run+0x150/0x240 kernel/task_work.c:227 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x86f/0x2bf0 kernel/exit.c:966 do_group_exit+0xd3/0x2a0 kernel/exit.c:1107 get_signal+0x2671/0x26d0 kernel/signal.c:3034 arch_do_signal_or_restart+0x8f/0x790 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x85/0x130 kernel/entry/common.c:40 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x426/0xfa0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff8880751be080 which belongs to the cache skbuff_small_head of size 704 The buggy address is located 64 bytes to the right of allocated 704-byte region [ffff8880751be080, ffff8880751be340) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x751bc head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 ksm flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88801e285c80 ffffea00017b5700 dead000000000003 raw: 0000000000000000 0000000000130013 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801e285c80 ffffea00017b5700 dead000000000003 head: 0000000000000000 0000000000130013 00000000f5000000 0000000000000000 head: 00fff00000000002 ffffea0001d46f01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5816, tgid 5816 (syz-executor), ts 332811865000, free_ts 322775761522 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1af/0x220 mm/page_alloc.c:1845 prep_new_page mm/page_alloc.c:1853 [inline] get_page_from_freelist+0x10a3/0x3a30 mm/page_alloc.c:3879 __alloc_frozen_pages_noprof+0x25f/0x2470 mm/page_alloc.c:5178 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:3059 [inline] allocate_slab mm/slub.c:3232 [inline] new_slab+0x24a/0x360 mm/slub.c:3286 ___slab_alloc+0xd79/0x1a50 mm/slub.c:4655 __slab_alloc.constprop.0+0x63/0x110 mm/slub.c:4778 __slab_alloc_node mm/slub.c:4854 [inline] slab_alloc_node mm/slub.c:5276 [inline] kmem_cache_alloc_node_noprof+0x43c/0x770 mm/slub.c:5340 kmalloc_reserve+0x18b/0x2c0 net/core/skbuff.c:579 __alloc_skb+0x166/0x380 net/core/skbuff.c:670 alloc_skb_fclone include/linux/skbuff.h:1433 [inline] tcp_stream_alloc_skb+0x34/0x560 net/ipv4/tcp.c:912 tso_fragment net/ipv4/tcp_output.c:2324 [inline] tcp_write_xmit+0x8af/0x86e0 net/ipv4/tcp_output.c:2985 __tcp_push_pending_frames+0xaf/0x390 net/ipv4/tcp_output.c:3182 tcp_push_pending_frames include/net/tcp.h:2221 [inline] tcp_data_snd_check net/ipv4/tcp_input.c:5880 [inline] tcp_rcv_established+0x119f/0x3700 net/ipv4/tcp_input.c:6350 tcp_v4_do_rcv+0xc65/0x10a0 net/ipv4/tcp_ipv4.c:1931 sk_backlog_rcv include/net/sock.h:1158 [inline] __release_sock+0x361/0x450 net/core/sock.c:3180 page last free pid 7628 tgid 7628 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:2901 ops_free_list net/core/net_namespace.c:215 [inline] ops_undo_list+0x487/0xab0 net/core/net_namespace.c:256 cleanup_net+0x41b/0x8b0 net/core/net_namespace.c:695 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263 process_scheduled_works kernel/workqueue.c:3346 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427 kthread+0x3c5/0x780 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 Memory state around the buggy address: ffff8880751be280: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8880751be300: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc >ffff8880751be380: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00 ^ ffff8880751be400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8880751be480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================