================================================================== 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 ffff8880663963c0 by task syz.4.5495/24709 CPU: 0 UID: 0 PID: 24709 Comm: syz.4.5495 Tainted: G U L syzkaller #0 PREEMPT(full) Tainted: [U]=USER, [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 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 iter_file_splice_write+0x830/0x10a0 fs/splice.c:736 do_splice_from fs/splice.c:936 [inline] direct_splice_actor+0x192/0x6c0 fs/splice.c:1159 splice_direct_to_actor+0x345/0xa30 fs/splice.c:1103 do_splice_direct_actor fs/splice.c:1202 [inline] do_splice_direct+0x174/0x240 fs/splice.c:1228 do_sendfile+0xadc/0xe20 fs/read_write.c:1372 __do_sys_sendfile64 fs/read_write.c:1433 [inline] __se_sys_sendfile64 fs/read_write.c:1419 [inline] __x64_sys_sendfile64+0x1d8/0x220 fs/read_write.c:1419 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: 0033:0x7f41dd19c799 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:00007f41de062028 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f41dd416090 RCX: 00007f41dd19c799 RDX: 0000000000000000 RSI: 000000000000000d RDI: 0000000000000007 RBP: 00007f41dd232bd9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f41dd416128 R14: 00007f41dd416090 R15: 00007fff71d8d858 The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x826 pfn:0x66396 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f0(buddy) raw: 00fff00000000000 ffffea0000b6ed08 ffffea0001e04208 0000000000000000 raw: 0000000000000826 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 0x1c20c2(__GFP_HIGHMEM|__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 20110, tgid 20106 (syz.0.5221), ts 1463963410671, free_ts 1464436003214 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_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2484 folio_alloc_mpol_noprof+0x36/0x340 mm/mempolicy.c:2503 shmem_alloc_folio+0x135/0x160 mm/shmem.c:1930 shmem_alloc_and_add_folio+0x833/0xd40 mm/shmem.c:1959 shmem_get_folio_gfp+0xab1/0x1900 mm/shmem.c:2555 shmem_fault+0x1f9/0xa20 mm/shmem.c:2768 __do_fault+0x10d/0x550 mm/memory.c:5363 do_shared_fault mm/memory.c:5862 [inline] do_fault+0x2db/0x1950 mm/memory.c:5936 do_pte_missing mm/memory.c:4477 [inline] handle_pte_fault mm/memory.c:6316 [inline] __handle_mm_fault+0x180f/0x2b60 mm/memory.c:6454 handle_mm_fault+0x36d/0xa20 mm/memory.c:6623 faultin_page mm/gup.c:1126 [inline] __get_user_pages+0xf9c/0x34d0 mm/gup.c:1428 __get_user_pages_locked mm/gup.c:1692 [inline] __gup_longterm_locked+0x279/0x16f0 mm/gup.c:2481 gup_fast_fallback+0x18c6/0x2460 mm/gup.c:3209 page last free pid 20110 tgid 20106 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1433 [inline] free_unref_folios+0xaea/0x1790 mm/page_alloc.c:3040 folios_put_refs+0x53c/0x840 mm/swap.c:1002 folio_batch_release include/linux/pagevec.h:101 [inline] shmem_undo_range+0x5e5/0x1570 mm/shmem.c:1149 shmem_truncate_range mm/shmem.c:1277 [inline] shmem_evict_inode+0x39e/0xbd0 mm/shmem.c:1407 evict+0x3c2/0xad0 fs/inode.c:846 iput_final fs/inode.c:1966 [inline] iput.part.0+0x605/0xf50 fs/inode.c:2015 iput+0x35/0x40 fs/inode.c:1981 dentry_unlink_inode+0x2a1/0x490 fs/dcache.c:467 __dentry_kill+0x1d0/0x600 fs/dcache.c:670 finish_dput+0x76/0x480 fs/dcache.c:879 dput.part.0+0x456/0x570 fs/dcache.c:928 dput+0x1f/0x30 fs/dcache.c:920 __fput+0x519/0xb40 fs/file_table.c:477 task_work_run+0x150/0x240 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x829/0x2aa0 kernel/exit.c:971 do_group_exit+0xd5/0x2a0 kernel/exit.c:1112 Memory state around the buggy address: ffff888066396280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888066396300: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff888066396380: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff888066396400: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888066396480: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ==================================================================