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BUG: KASAN: use-after-free in scr_memcpyw include/linux/vt_buffer.h:38 [inline]
BUG: KASAN: use-after-free in fbcon_prepare_logo+0xa03/0xc70 drivers/video/fbdev/core/fbcon.c:623
Read of size 256 at addr ffff88807754e3c0 by task syz.1.1542/13589

CPU: 1 UID: 0 PID: 13589 Comm: syz.1.1542 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:
 <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: 0033:0x7f0027d8eec9
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:00007f0028ceb038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f0027fe6090 RCX: 00007f0027d8eec9
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000003
RBP: 00007f0027e11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0027fe6128 R14: 00007f0027fe6090 R15: 00007ffc76d1a8a8
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88807754fe00 pfn:0x7754e
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f0(buddy)
raw: 00fff00000000000 ffffea00010dec88 ffffea0001de4288 0000000000000000
raw: ffff88807754fe00 0000000000000001 00000000f0000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 12890, tgid 12890 (rm), ts 582936170311, free_ts 599937606721
 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
 __kmem_cache_alloc_bulk+0x225/0x770 mm/slub.c:7375
 refill_sheaf mm/slub.c:2617 [inline]
 kmem_cache_prefill_sheaf+0x1c3/0x430 mm/slub.c:5396
 mt_get_sheaf lib/maple_tree.c:187 [inline]
 mas_alloc_nodes lib/maple_tree.c:1138 [inline]
 mas_preallocate+0xb00/0x11f0 lib/maple_tree.c:5192
 vma_iter_prealloc mm/vma.h:442 [inline]
 __mmap_new_vma mm/vma.c:2470 [inline]
 __mmap_region+0x117f/0x27a0 mm/vma.c:2670
 mmap_region+0x1ab/0x3f0 mm/vma.c:2740
 do_mmap+0xa3e/0x1210 mm/mmap.c:558
 vm_mmap_pgoff+0x29e/0x470 mm/util.c:581
 ksys_mmap_pgoff+0x7d/0x5c0 mm/mmap.c:604
 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:89 [inline]
 __se_sys_mmap arch/x86/kernel/sys_x86_64.c:82 [inline]
 __x64_sys_mmap+0x125/0x190 arch/x86/kernel/sys_x86_64.c:82
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
page last free pid 13165 tgid 13164 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:2906
 discard_slab mm/slub.c:3310 [inline]
 __put_partials+0x130/0x170 mm/slub.c:3857
 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:4955 [inline]
 slab_alloc_node mm/slub.c:5265 [inline]
 __do_kmalloc_node mm/slub.c:5626 [inline]
 __kmalloc_noprof+0x2e8/0x880 mm/slub.c:5639
 kmalloc_noprof include/linux/slab.h:961 [inline]
 kzalloc_noprof include/linux/slab.h:1094 [inline]
 ops_init+0x77/0x5f0 net/core/net_namespace.c:127
 setup_net+0x100/0x390 net/core/net_namespace.c:445
 copy_net_ns+0x2f8/0x690 net/core/net_namespace.c:580
 create_new_namespaces+0x3ea/0xa90 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0xc0/0x1f0 kernel/nsproxy.c:218
 ksys_unshare+0x45b/0xa40 kernel/fork.c:3129
 __do_sys_unshare kernel/fork.c:3200 [inline]
 __se_sys_unshare kernel/fork.c:3198 [inline]
 __x64_sys_unshare+0x31/0x40 kernel/fork.c:3198
 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:
 ffff88807754e280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88807754e300: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88807754e380: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                           ^
 ffff88807754e400: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88807754e480: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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