================================================================== 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:630 Read of size 256 at addr ffff888075c4e3c0 by task syz.4.2579/19433 CPU: 0 UID: 0 PID: 19433 Comm: syz.4.2579 Tainted: G U syzkaller #0 PREEMPT(full) Tainted: [U]=USER Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 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:183 [inline] kasan_check_range+0x100/0x1b0 mm/kasan/generic.c:189 __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:630 fbcon_init+0xd77/0x1900 drivers/video/fbdev/core/fbcon.c:1163 visual_init+0x320/0x620 drivers/tty/vt/vt.c:1019 do_bind_con_driver.isra.0+0x57a/0xbf0 drivers/tty/vt/vt.c:3915 vt_bind drivers/tty/vt/vt.c:4071 [inline] store_bind+0x61d/0x760 drivers/tty/vt/vt.c:4143 dev_attr_store+0x55/0x80 drivers/base/core.c:2437 sysfs_kf_write+0xef/0x150 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x351/0x510 fs/kernfs/file.c:334 iter_file_splice_write+0xa21/0x12e0 fs/splice.c:738 do_splice_from fs/splice.c:938 [inline] direct_splice_actor+0x18f/0x6c0 fs/splice.c:1161 splice_direct_to_actor+0x342/0xa30 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/0x490 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f8e5dd8ebe9 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:00007f8e5ec3a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f8e5dfb6090 RCX: 00007f8e5dd8ebe9 RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000004 RBP: 00007f8e5de11e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f8e5dfb6128 R14: 00007f8e5dfb6090 R15: 00007fff75f1b998 The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x75c4e flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000000 0000000000000000 ffffea0001d71390 0000000000000000 raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as freed page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 18820, tgid 18814 (syz.3.2444), ts 848243745525, free_ts 865075235493 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1851 prep_new_page mm/page_alloc.c:1859 [inline] get_page_from_freelist+0x132b/0x38e0 mm/page_alloc.c:3858 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:5148 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:2487 [inline] allocate_slab mm/slub.c:2655 [inline] new_slab+0x247/0x330 mm/slub.c:2709 ___slab_alloc+0xcf2/0x1740 mm/slub.c:3891 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3981 __slab_alloc_node mm/slub.c:4056 [inline] slab_alloc_node mm/slub.c:4217 [inline] kmem_cache_alloc_node_noprof+0xf5/0x3b0 mm/slub.c:4281 kmalloc_reserve+0x18b/0x2c0 net/core/skbuff.c:578 __alloc_skb+0x166/0x380 net/core/skbuff.c:669 alloc_skb include/linux/skbuff.h:1336 [inline] __ip6_append_data+0x2b74/0x4750 net/ipv6/ip6_output.c:1671 ip6_append_data+0x1bd/0x4c0 net/ipv6/ip6_output.c:1860 rawv6_sendmsg+0x163d/0x4820 net/ipv6/raw.c:911 inet_sendmsg+0x119/0x140 net/ipv4/af_inet.c:851 sock_sendmsg_nosec net/socket.c:714 [inline] __sock_sendmsg net/socket.c:729 [inline] ____sys_sendmsg+0x973/0xc70 net/socket.c:2614 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2668 page last free pid 13517 tgid 13517 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1395 [inline] __free_frozen_pages+0x7d5/0x10f0 mm/page_alloc.c:2895 discard_slab mm/slub.c:2753 [inline] __put_partials+0x165/0x1c0 mm/slub.c:3218 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:340 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4180 [inline] slab_alloc_node mm/slub.c:4229 [inline] kmem_cache_alloc_noprof+0x1cb/0x3b0 mm/slub.c:4236 anon_vma_alloc mm/rmap.c:94 [inline] anon_vma_fork+0xe6/0x620 mm/rmap.c:360 dup_mmap+0x152e/0x21d0 mm/mmap.c:1797 dup_mm kernel/fork.c:1485 [inline] copy_mm kernel/fork.c:1537 [inline] copy_process+0x4081/0x7690 kernel/fork.c:2175 kernel_clone+0xfc/0x930 kernel/fork.c:2605 __do_sys_clone+0xce/0x120 kernel/fork.c:2748 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff888075c4e280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888075c4e300: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff888075c4e380: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff888075c4e400: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888075c4e480: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ==================================================================