================================================================== BUG: KASAN: use-after-free in scr_memcpyw include/linux/vt_buffer.h:38 [inline] BUG: KASAN: use-after-free in fbcon_prepare_logo+0x94e/0xc60 drivers/video/fbdev/core/fbcon.c:646 Read of size 256 at addr ffff8880128223c0 by task syz.0.1334/12751 CPU: 0 UID: 0 PID: 12751 Comm: syz.0.1334 Tainted: G U L syzkaller #0 PREEMPT(full) Tainted: [U]=USER, [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/27/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x156/0x4c9 mm/kasan/report.c:482 kasan_report+0xdf/0x1e0 mm/kasan/report.c:595 check_region_inline mm/kasan/generic.c:186 [inline] kasan_check_range+0x10f/0x1e0 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+0x94e/0xc60 drivers/video/fbdev/core/fbcon.c:646 fbcon_init+0x10a0/0x1820 drivers/video/fbdev/core/fbcon.c:1180 visual_init+0x320/0x620 drivers/tty/vt/vt.c:1014 do_bind_con_driver.isra.0+0x636/0x9c0 drivers/tty/vt/vt.c:3954 vt_bind drivers/tty/vt/vt.c:4110 [inline] store_bind+0x609/0x730 drivers/tty/vt/vt.c:4182 dev_attr_store+0x58/0x80 drivers/base/core.c:2437 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:142 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:352 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6ac/0x1070 fs/read_write.c:688 ksys_write+0x12a/0x250 fs/read_write.c:740 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fbc1bb9c799 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fbc1ca41028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fbc1be15fa0 RCX: 00007fbc1bb9c799 RDX: 0000000000000084 RSI: 0000200000000040 RDI: 0000000000000003 RBP: 00007fbc1bc32c99 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fbc1be16038 R14: 00007fbc1be15fa0 R15: 00007fff8e662b88 The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888012823e00 pfn:0x12822 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f0(buddy) raw: 00fff00000000000 ffffea000097f988 ffffea00004a2888 0000000000000000 raw: ffff888012823e00 0000000000000001 00000000f0000000 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as freed page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5743, tgid 5743 (rm), ts 77527200811, free_ts 108657153179 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x153/0x170 mm/page_alloc.c:1889 prep_new_page mm/page_alloc.c:1897 [inline] get_page_from_freelist+0x111d/0x3140 mm/page_alloc.c:3962 __alloc_frozen_pages_noprof+0x27c/0x2ba0 mm/page_alloc.c:5250 alloc_slab_page mm/slub.c:3296 [inline] allocate_slab mm/slub.c:3485 [inline] new_slab+0xa6/0x6c0 mm/slub.c:3543 refill_objects+0x26b/0x400 mm/slub.c:7178 refill_sheaf mm/slub.c:2818 [inline] __prefill_sheaf_pfmemalloc+0x5f/0xb0 mm/slub.c:4939 kmem_cache_prefill_sheaf+0x1ba/0x4c0 mm/slub.c:5028 mt_get_sheaf lib/maple_tree.c:189 [inline] mas_alloc_nodes+0x2c3/0x390 lib/maple_tree.c:1140 mas_preallocate+0x39c/0xf10 lib/maple_tree.c:5194 vma_iter_prealloc mm/vma.h:568 [inline] vma_link+0x12c/0x710 mm/vma.c:1829 insert_vm_struct+0xf4/0x2d0 mm/vma.c:3295 __install_special_mapping mm/mmap.c:1474 [inline] _install_special_mapping+0x187/0x3d0 mm/mmap.c:1510 map_vdso+0x1b0/0x560 arch/x86/entry/vdso/vma.c:168 arch_setup_additional_pages+0x41/0x60 arch/x86/entry/vdso/vma.c:238 load_elf_binary+0x200d/0x51b0 fs/binfmt_elf.c:1292 search_binary_handler fs/exec.c:1664 [inline] exec_binprm fs/exec.c:1696 [inline] bprm_execve fs/exec.c:1748 [inline] bprm_execve+0x8fb/0x1680 fs/exec.c:1724 page last free pid 5811 tgid 5811 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1433 [inline] __free_frozen_pages+0x7e1/0x10d0 mm/page_alloc.c:2978 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x47/0xe0 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4542 [inline] slab_alloc_node mm/slub.c:4869 [inline] kmem_cache_alloc_node_noprof+0x25a/0x6f0 mm/slub.c:4921 __alloc_skb+0x140/0x710 net/core/skbuff.c:702 alloc_skb_fclone include/linux/skbuff.h:1433 [inline] tcp_stream_alloc_skb+0x34/0x660 net/ipv4/tcp.c:945 tcp_sendmsg_locked+0x1396/0x45e0 net/ipv4/tcp.c:1270 tcp_sendmsg+0x2e/0x50 net/ipv4/tcp.c:1465 inet_sendmsg+0xb9/0x140 net/ipv4/af_inet.c:865 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] sock_write_iter+0x4ea/0x5a0 net/socket.c:1195 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6ac/0x1070 fs/read_write.c:688 ksys_write+0x1f8/0x250 fs/read_write.c:740 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff888012822280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888012822300: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff888012822380: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff888012822400: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888012822480: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ==================================================================