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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:623
Read of size 28 at addr ffff888030f50cd0 by task syz.1.1821/15649

CPU: 0 UID: 0 PID: 15649 Comm: syz.1.1821 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
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: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: 0033:0x7f446358eec9
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:00007f44643f2038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f44637e6270 RCX: 00007f446358eec9
RDX: 0000000000000000 RSI: 0000000000000007 RDI: 0000000000000003
RBP: 00007f4463611f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f44637e6308 R14: 00007f44637e6270 R15: 00007fffa05e93e8
 </TASK>

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]
 kset_create lib/kobject.c:965 [inline]
 kset_create_and_add+0x4d/0x190 lib/kobject.c:1008
 register_queue_kobjects net/core/net-sysfs.c:2106 [inline]
 netdev_register_kobject+0x1ef/0x3d0 net/core/net-sysfs.c:2362
 register_netdevice+0x13dc/0x2270 net/core/dev.c:11294
 register_netdev+0x34/0x50 net/core/dev.c:11410
 rose_proto_init+0x253/0x850 net/rose/af_rose.c:1592
 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 ffff888030f50c00
 which belongs to the cache kmalloc-192 of size 192
The buggy address is located 56 bytes to the right of
 allocated 152-byte region [ffff888030f50c00, ffff888030f50c98)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x30f50
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88813ffa63c0 ffffea0000abda40 dead000000000006
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 1, tgid 1 (swapper/0), ts 28196659387, 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:3039 [inline]
 allocate_slab mm/slub.c:3212 [inline]
 new_slab+0x24a/0x360 mm/slub.c:3266
 ___slab_alloc+0xdc4/0x1ae0 mm/slub.c:4636
 __slab_alloc.constprop.0+0x63/0x110 mm/slub.c:4755
 __slab_alloc_node mm/slub.c:4831 [inline]
 slab_alloc_node mm/slub.c:5253 [inline]
 __kmalloc_cache_noprof+0x477/0x780 mm/slub.c:5743
 kmalloc_noprof include/linux/slab.h:957 [inline]
 kzalloc_noprof include/linux/slab.h:1094 [inline]
 call_usermodehelper_setup+0xaf/0x360 kernel/umh.c:362
 kobject_uevent_env+0x1690/0x1870 lib/kobject_uevent.c:628
 netdev_queue_add_kobject net/core/net-sysfs.c:2013 [inline]
 netdev_queue_update_kobjects+0x1a7/0x720 net/core/net-sysfs.c:2056
 register_queue_kobjects net/core/net-sysfs.c:2119 [inline]
 netdev_register_kobject+0x2b3/0x3d0 net/core/net-sysfs.c:2362
 register_netdevice+0x13dc/0x2270 net/core/dev.c:11294
 register_netdev+0x34/0x50 net/core/dev.c:11410
 rose_proto_init+0x253/0x850 net/rose/af_rose.c:1592
 do_one_initcall+0x123/0x6e0 init/main.c:1283
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888030f50b80: 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888030f50c00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888030f50c80: 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc
                                                 ^
 ffff888030f50d00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888030f50d80: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc
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