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BUG: KASAN: use-after-free in memcpy include/linux/string.h:348 [inline]
BUG: KASAN: use-after-free in soft_cursor+0x439/0xa30 drivers/video/fbdev/core/softcursor.c:70
Read of size 3 at addr ffff8880836c8dc1 by task syz-executor.4/26698

CPU: 1 PID: 26698 Comm: syz-executor.4 Not tainted 4.19.106-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x197/0x210 lib/dump_stack.c:118
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report mm/kasan/report.c:412 [inline]
 kasan_report.cold+0x8c/0x2ba mm/kasan/report.c:396
 check_memory_region_inline mm/kasan/kasan.c:260 [inline]
 check_memory_region+0x123/0x190 mm/kasan/kasan.c:267
 memcpy+0x24/0x50 mm/kasan/kasan.c:302
 memcpy include/linux/string.h:348 [inline]
 soft_cursor+0x439/0xa30 drivers/video/fbdev/core/softcursor.c:70
 bit_cursor+0x12fc/0x1a60 drivers/video/fbdev/core/bitblit.c:386
 fbcon_cursor+0x58a/0x7b0 drivers/video/fbdev/core/fbcon.c:1369
 hide_cursor+0x9e/0x300 drivers/tty/vt/vt.c:895
 redraw_screen+0x2ee/0x8e0 drivers/tty/vt/vt.c:988
 vc_do_resize+0x118e/0x14a0 drivers/tty/vt/vt.c:1287
 vc_resize+0x4d/0x60 drivers/tty/vt/vt.c:1307
 vt_ioctl+0x1fe0/0x2530 drivers/tty/vt/vt_ioctl.c:887
 tty_ioctl+0x7f3/0x1510 drivers/tty/tty_io.c:2669
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0xd5f/0x1380 fs/ioctl.c:688
 ksys_ioctl+0xab/0xd0 fs/ioctl.c:705
 __do_sys_ioctl fs/ioctl.c:712 [inline]
 __se_sys_ioctl fs/ioctl.c:710 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:710
 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45c449
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f869fd3fc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f869fd406d4 RCX: 000000000045c449
RDX: 0000000020000000 RSI: 000000000000560a RDI: 0000000000000003
RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000054d R14: 00000000004c79f1 R15: 000000000076bf2c

Allocated by task 8409:
 save_stack+0x45/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc mm/kasan/kasan.c:553 [inline]
 kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:531
 kmem_cache_alloc_trace+0x152/0x760 mm/slab.c:3625
 kmalloc include/linux/slab.h:515 [inline]
 kzalloc include/linux/slab.h:709 [inline]
 kernfs_fop_open+0x2ac/0xd80 fs/kernfs/file.c:648
 do_dentry_open+0x4c3/0x1210 fs/open.c:796
 vfs_open+0xa0/0xd0 fs/open.c:905
 do_last fs/namei.c:3421 [inline]
 path_openat+0x10d8/0x44a0 fs/namei.c:3537
 do_filp_open+0x1a1/0x280 fs/namei.c:3567
 do_sys_open+0x3fe/0x550 fs/open.c:1088
 __do_sys_open fs/open.c:1106 [inline]
 __se_sys_open fs/open.c:1101 [inline]
 __x64_sys_open+0x7e/0xc0 fs/open.c:1101
 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 8409:
 save_stack+0x45/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
 __cache_free mm/slab.c:3503 [inline]
 kfree+0xcf/0x220 mm/slab.c:3822
 kernfs_fop_release+0x129/0x1a0 fs/kernfs/file.c:783
 __fput+0x2dd/0x8b0 fs/file_table.c:278
 ____fput+0x16/0x20 fs/file_table.c:309
 task_work_run+0x145/0x1c0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:193 [inline]
 exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:167
 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:271 [inline]
 do_syscall_64+0x53d/0x620 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8880836c8d40
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 129 bytes inside of
 512-byte region [ffff8880836c8d40, ffff8880836c8f40)
The buggy address belongs to the page:
page:ffffea00020db200 count:1 mapcount:0 mapping:ffff88812c31c940 index:0xffff8880836c8840
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffffea00024f27c8 ffffea0002827508 ffff88812c31c940
raw: ffff8880836c8840 ffff8880836c80c0 0000000100000005 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880836c8c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880836c8d00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
>ffff8880836c8d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff8880836c8e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880836c8e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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