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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+0x94e/0xc60 drivers/video/fbdev/core/fbcon.c:646
Read of size 26 at addr ffff8880375120ea by task syz.1.4945/29416

CPU: 0 UID: 0 PID: 29416 Comm: syz.1.4945 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x156/0x4c9 mm/kasan/report.c:482
 kasan_report+0xdf/0x1e0 mm/kasan/report.c:595
 check_region_inline mm/kasan/generic.c:186 [inline]
 kasan_check_range+0x10f/0x1e0 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+0x94e/0xc60 drivers/video/fbdev/core/fbcon.c:646
 fbcon_init+0x10a0/0x1820 drivers/video/fbdev/core/fbcon.c:1180
 visual_init+0x320/0x620 drivers/tty/vt/vt.c:1014
 do_bind_con_driver.isra.0+0x636/0x9c0 drivers/tty/vt/vt.c:3962
 vt_bind drivers/tty/vt/vt.c:4118 [inline]
 store_bind+0x609/0x730 drivers/tty/vt/vt.c:4190
 dev_attr_store+0x58/0x80 drivers/base/core.c:2437
 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:142
 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:352
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1070 fs/read_write.c:688
 ksys_write+0x12a/0x250 fs/read_write.c:740
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f75ff99c799
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f7600779028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f75ffc15fa0 RCX: 00007f75ff99c799
RDX: 0000000000000084 RSI: 0000200000000040 RDI: 0000000000000003
RBP: 00007f75ffa32c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f75ffc16038 R14: 00007f75ffc15fa0 R15: 00007ffff5f8a3d8
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888037512000 pfn:0x37512
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f0(buddy)
raw: 00fff00000000000 ffffea0002757b08 ffffea0001ef5608 0000000000000000
raw: ffff888037512000 0000000000000000 00000000f0000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd00(GFP_NOIO|__GFP_ZERO), pid 26885, tgid 26882 (syz.2.4447), ts 1279557741917, free_ts 1279616214548
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x153/0x170 mm/page_alloc.c:1889
 prep_new_page mm/page_alloc.c:1897 [inline]
 get_page_from_freelist+0x111d/0x3140 mm/page_alloc.c:3962
 __alloc_frozen_pages_noprof+0x27c/0x2ba0 mm/page_alloc.c:5250
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2484
 alloc_frozen_pages_noprof mm/mempolicy.c:2555 [inline]
 alloc_pages_noprof+0x131/0x390 mm/mempolicy.c:2575
 relay_alloc_buf kernel/relay.c:121 [inline]
 relay_create_buf kernel/relay.c:160 [inline]
 relay_open_buf.part.0+0x261/0xb70 kernel/relay.c:388
 relay_open_buf kernel/relay.c:536 [inline]
 relay_open+0x7b9/0xa00 kernel/relay.c:517
 blk_trace_setup_prepare+0x35c/0x6c0 kernel/trace/blktrace.c:715
 blk_trace_setup+0x217/0x440 kernel/trace/blktrace.c:789
 blk_trace_ioctl+0x245/0x320 kernel/trace/blktrace.c:937
 blkdev_ioctl+0x17c/0x6f0 block/ioctl.c:793
 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+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 26885 tgid 26882 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0x7e1/0x10d0 mm/page_alloc.c:2978
 relay_destroy_buf+0x11a/0x3e0 kernel/relay.c:199
 relay_remove_buf kernel/relay.c:219 [inline]
 kref_put include/linux/kref.h:65 [inline]
 relay_close_buf+0x13b/0x1a0 kernel/relay.c:434
 relay_close kernel/relay.c:663 [inline]
 relay_close+0x36a/0x4b0 kernel/relay.c:649
 blk_trace_free+0x37/0x170 kernel/trace/blktrace.c:471
 blk_trace_cleanup kernel/trace/blktrace.c:539 [inline]
 __blk_trace_remove+0x81/0x180 kernel/trace/blktrace.c:552
 blk_trace_remove kernel/trace/blktrace.c:562 [inline]
 blk_trace_ioctl+0x26b/0x320 kernel/trace/blktrace.c:952
 blkdev_common_ioctl+0x170c/0x2ba0 block/ioctl.c:724
 blkdev_ioctl+0x43b/0x6f0 block/ioctl.c:798
 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+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888037511f80: 00 00 00 04 fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888037512000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888037512080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                          ^
 ffff888037512100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888037512180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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