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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 ffff888046c13260 by task syz.2.3278/22832

CPU: 0 UID: 0 PID: 22832 Comm: syz.2.3278 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+0xa24/0x12b0 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/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7588f8f7c9
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:00007f7589dd3038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f75891e6180 RCX: 00007f7588f8f7c9
RDX: 0000000000000000 RSI: 0000000000000008 RDI: 0000000000000004
RBP: 00007f7589013f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f75891e6218 R14: 00007f75891e6180 R15: 00007ffcccd146b8
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888046c13740 pfn:0x46c10
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: ffff888046c13740 0000000000000000 00000000f8000000 0000000000000000
head: 00fff00000000040 0000000000000000 dead000000000122 0000000000000000
head: ffff888046c13740 0000000000000000 00000000f8000000 0000000000000000
head: 00fff00000000002 ffffea00011b0401 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 22832, tgid 22821 (syz.2.3278), ts 1172838354187, free_ts 1166286164921
 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+0xd0b/0x31a0 mm/page_alloc.c:3879
 __alloc_frozen_pages_noprof+0x25f/0x2440 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+0xa24/0x12b0 fs/splice.c:738
page last free pid 22742 tgid 22742 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
 discard_slab mm/slub.c:3330 [inline]
 __put_partials+0x130/0x170 mm/slub.c:3876
 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:4978 [inline]
 slab_alloc_node mm/slub.c:5288 [inline]
 kmem_cache_alloc_noprof+0x250/0x720 mm/slub.c:5295
 new_handle fs/jbd2/transaction.c:457 [inline]
 jbd2__journal_start+0x193/0x6a0 fs/jbd2/transaction.c:484
 __ext4_journal_start_sb+0x195/0x640 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:6510
 __mark_inode_dirty+0x1f7/0x1670 fs/fs-writeback.c:2587
 generic_update_time+0xcf/0xf0 fs/inode.c:2154
 inode_update_time fs/inode.c:2167 [inline]
 file_update_time_flags+0x410/0x520 fs/inode.c:2394
 ext4_page_mkwrite+0x33d/0x1880 fs/ext4/inode.c:6679
 do_page_mkwrite+0x174/0x380 mm/memory.c:3489
 do_shared_fault mm/memory.c:5792 [inline]
 do_fault mm/memory.c:5854 [inline]
 do_pte_missing+0x29c/0x4000 mm/memory.c:4362
 handle_pte_fault mm/memory.c:6195 [inline]
 __handle_mm_fault+0x14ca/0x2a30 mm/memory.c:6336

Memory state around the buggy address:
 ffff888046c13100: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
 ffff888046c13180: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
>ffff888046c13200: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
                                                       ^
 ffff888046c13280: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
 ffff888046c13300: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
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