================================================================== 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 ffff88802ce663c0 by task syz.1.600/8928 CPU: 0 UID: 0 PID: 8928 Comm: syz.1.600 Not tainted syzkaller #0 PREEMPT(full) 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: 0033:0x7f23e498f6c9 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:00007f23e5755038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f23e4be6090 RCX: 00007f23e498f6c9 RDX: 0000000000000000 RSI: 0000000000000007 RDI: 0000000000000003 RBP: 00007f23e4a11f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f23e4be6128 R14: 00007f23e4be6090 R15: 00007ffcab630e18 Allocated by task 1: kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_save_track+0x14/0x30 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:400 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:417 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] device_private_init drivers/base/core.c:3534 [inline] device_add+0xccc/0x1aa0 drivers/base/core.c:3585 __video_register_device+0x234b/0x5af0 drivers/media/v4l2-core/v4l2-dev.c:1076 video_register_device include/media/v4l2-dev.h:390 [inline] vivid_create_devnodes drivers/media/test-drivers/vivid/vivid-core.c:1613 [inline] vivid_create_instance drivers/media/test-drivers/vivid/vivid-core.c:2042 [inline] vivid_probe drivers/media/test-drivers/vivid/vivid-core.c:2095 [inline] vivid_probe+0x9618/0xb890 drivers/media/test-drivers/vivid/vivid-core.c:2080 platform_probe+0x106/0x1d0 drivers/base/platform.c:1405 call_driver_probe drivers/base/dd.c:581 [inline] really_probe+0x241/0xa90 drivers/base/dd.c:659 __driver_probe_device+0x1de/0x440 drivers/base/dd.c:801 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:831 __driver_attach+0x283/0x580 drivers/base/dd.c:1217 bus_for_each_dev+0x13e/0x1d0 drivers/base/bus.c:370 bus_add_driver+0x2e9/0x690 drivers/base/bus.c:678 driver_register+0x15c/0x4b0 drivers/base/driver.c:249 vivid_init+0x5eb/0x8c0 drivers/media/test-drivers/vivid/vivid-core.c:2294 do_one_initcall+0x123/0x6e0 init/main.c:1283 do_initcall_level init/main.c:1345 [inline] do_initcalls init/main.c:1361 [inline] do_basic_setup init/main.c:1380 [inline] kernel_init_freeable+0x5c8/0x920 init/main.c:1593 kernel_init+0x1c/0x2b0 init/main.c:1483 ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 The buggy address belongs to the object at ffff88802ce66000 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 688 bytes to the right of allocated 272-byte region [ffff88802ce66000, ffff88802ce66110) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2ce64 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: f5(slab) raw: 00fff00000000040 ffff88813ffa6c80 dead000000000122 0000000000000000 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88813ffa6c80 dead000000000122 0000000000000000 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000002 ffffea0000b39901 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 2, tgid 2 (kthreadd), ts 28667212697, free_ts 0 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 alloc_slab_page mm/slub.c:3055 [inline] allocate_slab mm/slub.c:3228 [inline] new_slab+0x24a/0x360 mm/slub.c:3282 ___slab_alloc+0xd79/0x1a50 mm/slub.c:4651 __slab_alloc.constprop.0+0x63/0x110 mm/slub.c:4774 __slab_alloc_node mm/slub.c:4850 [inline] slab_alloc_node mm/slub.c:5272 [inline] __kmalloc_cache_noprof+0x477/0x780 mm/slub.c:5762 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] set_kthread_struct+0xcb/0x380 kernel/kthread.c:125 copy_process+0x310e/0x76a0 kernel/fork.c:2110 kernel_clone+0xfc/0x930 kernel/fork.c:2609 kernel_thread+0xd7/0x120 kernel/fork.c:2670 create_kthread kernel/kthread.c:486 [inline] kthreadd+0x503/0x800 kernel/kthread.c:846 ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 page_owner free stack trace missing Memory state around the buggy address: ffff88802ce66280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88802ce66300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88802ce66380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff88802ce66400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88802ce66480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================