================================================================== 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:623 Read of size 256 at addr ffff8880477cef60 by task syz.1.2427/19539 CPU: 0 UID: 0 PID: 19539 Comm: syz.1.2427 Tainted: G U syzkaller #0 PREEMPT(full) Tainted: [U]=USER Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 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:623 fbcon_init+0xd77/0x1900 drivers/video/fbdev/core/fbcon.c:1156 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: 0033:0x7f4dd338f6c9 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:00007f4dd415a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f4dd35e5fa0 RCX: 00007f4dd338f6c9 RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000004 RBP: 00007f4dd3411f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4dd35e6038 R14: 00007f4dd35e5fa0 R15: 00007ffe36e3e498 The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x4d8 pfn:0x477cc 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: 00000000000004d8 0000000000000000 00000000f8000000 0000000000000000 head: 00fff00000000040 0000000000000000 dead000000000122 0000000000000000 head: 00000000000004d8 0000000000000000 00000000f8000000 0000000000000000 head: 00fff00000000002 ffffea00011df301 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 19539, tgid 19538 (syz.1.2427), ts 739922937419, free_ts 739806134047 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1850 prep_new_page mm/page_alloc.c:1858 [inline] get_page_from_freelist+0x10a3/0x3a30 mm/page_alloc.c:3884 __alloc_frozen_pages_noprof+0x25f/0x2470 mm/page_alloc.c:5183 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416 ___kmalloc_large_node+0xed/0x160 mm/slub.c:5587 __kmalloc_large_node_noprof+0x1c/0x70 mm/slub.c:5618 __do_kmalloc_node mm/slub.c:5634 [inline] __kmalloc_noprof.cold+0xc/0x62 mm/slub.c:5658 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:1153 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 19539 tgid 19538 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1394 [inline] free_unref_folios+0xa31/0x1610 mm/page_alloc.c:2963 folios_put_refs+0x4be/0x750 mm/swap.c:1002 folio_batch_release include/linux/pagevec.h:101 [inline] mapping_try_invalidate+0x2fd/0x3c0 mm/truncate.c:554 invalidate_bdev+0x88/0xa0 block/bdev.c:102 blkdev_flushbuf block/ioctl.c:440 [inline] blkdev_common_ioctl+0xf11/0x2470 block/ioctl.c:572 blkdev_ioctl+0x1cb/0x6d0 block/ioctl.c:699 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 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: ffff8880477cef00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8880477cef80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff8880477cf000: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe ^ ffff8880477cf080: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe ffff8880477cf100: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe ==================================================================