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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 ffff8880256fbf60 by task syz.3.1895/15261

CPU: 1 UID: 0 PID: 15261 Comm: syz.3.1895 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 __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: 0033:0x7f6647d8f7c9
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:00007f6645b91038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f6647fe6270 RCX: 00007f6647d8f7c9
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 0000000000000004
RBP: 00007f6647e13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6647fe6308 R14: 00007f6647fe6270 R15: 00007ffe75de4ec8
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8880256fba80 pfn:0x256f8
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f8(unknown)
raw: 00fff00000000040 0000000000000000 dead000000000122 0000000000000000
raw: ffff8880256fba80 0000000000000000 00000000f8000000 0000000000000000
head: 00fff00000000040 0000000000000000 dead000000000122 0000000000000000
head: ffff8880256fba80 0000000000000000 00000000f8000000 0000000000000000
head: 00fff00000000002 ffffea000095be01 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 0x140dc0(GFP_USER|__GFP_ZERO|__GFP_COMP), pid 15261, tgid 15254 (syz.3.1895), ts 759647700713, free_ts 759615568438
 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
 ___kmalloc_large_node+0xed/0x160 mm/slub.c:5591
 __kmalloc_large_node_noprof+0x1c/0x70 mm/slub.c:5622
 __do_kmalloc_node mm/slub.c:5638 [inline]
 __kmalloc_noprof.cold+0xc/0x62 mm/slub.c:5662
 kmalloc_noprof include/linux/slab.h:961 [inline]
 kzalloc_noprof include/linux/slab.h:1094 [inline]
 vc_do_resize+0x1de/0x10e0 drivers/tty/vt/vt.c:1183
 vc_resize include/linux/vt_kern.h:49 [inline]
 fbcon_init+0xd53/0x1900 drivers/video/fbdev/core/fbcon.c:1155
 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
page last free pid 15261 tgid 15254 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
 vc_do_resize+0xe29/0x10e0 drivers/tty/vt/vt.c:1203
 vc_resize include/linux/vt_kern.h:49 [inline]
 fbcon_startup+0x427/0xba0 drivers/video/fbdev/core/fbcon.c:1009
 do_bind_con_driver.isra.0+0x20a/0xbf0 drivers/tty/vt/vt.c:3923
 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

Memory state around the buggy address:
 ffff8880256fbe00: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
 ffff8880256fbe80: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
>ffff8880256fbf00: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
                                                       ^
 ffff8880256fbf80: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
 ffff8880256fc000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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