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BUG: KASAN: slab-out-of-bounds in soft_cursor+0x3fe/0xdb0 drivers/video/fbdev/core/softcursor.c:70
Read of size 9 at addr ffff88809e00c930 by task syz-executor.4/16624

CPU: 1 PID: 16624 Comm: syz-executor.4 Not tainted 5.8.0-rc6-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+0x1f0/0x31e lib/dump_stack.c:118
 print_address_description+0x66/0x5a0 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report+0x132/0x1d0 mm/kasan/report.c:530
 check_memory_region_inline mm/kasan/generic.c:183 [inline]
 check_memory_region+0x2b5/0x2f0 mm/kasan/generic.c:192
 memcpy+0x25/0x60 mm/kasan/common.c:105
 soft_cursor+0x3fe/0xdb0 drivers/video/fbdev/core/softcursor.c:70
 bit_cursor+0x178a/0x2180 drivers/video/fbdev/core/bitblit.c:386
 hide_cursor+0x7e/0x310 drivers/tty/vt/vt.c:902
 redraw_screen+0x148/0x16f0 drivers/tty/vt/vt.c:1006
 vc_do_resize+0x1541/0x1ce0 drivers/tty/vt/vt.c:1314
 vt_ioctl+0x3185/0x3ec0 drivers/tty/vt/vt_ioctl.c:901
 tty_ioctl+0xee4/0x15c0 drivers/tty/tty_io.c:2656
 vfs_ioctl fs/ioctl.c:48 [inline]
 ksys_ioctl fs/ioctl.c:753 [inline]
 __do_sys_ioctl fs/ioctl.c:762 [inline]
 __se_sys_ioctl+0xf9/0x160 fs/ioctl.c:760
 do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45c1f9
Code: Bad RIP value.
RSP: 002b:00007f06618fcc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 000000000001b8c0 RCX: 000000000045c1f9
RDX: 00000000200003c0 RSI: 000000000000560a RDI: 0000000000000003
RBP: 000000000078bf40 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c
R13: 00007ffc3682867f R14: 00007f06618fd9c0 R15: 000000000078bf0c

Allocated by task 28736:
 save_stack mm/kasan/common.c:48 [inline]
 set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc+0x103/0x140 mm/kasan/common.c:494
 __do_kmalloc mm/slab.c:3656 [inline]
 __kmalloc+0x24b/0x330 mm/slab.c:3665
 kmalloc include/linux/slab.h:560 [inline]
 fbcon_set_font+0x2c4/0x970 drivers/video/fbdev/core/fbcon.c:2673
 con_font_set drivers/tty/vt/vt.c:4571 [inline]
 con_font_op+0xebc/0x1630 drivers/tty/vt/vt.c:4636
 vt_ioctl+0x179d/0x3ec0 drivers/tty/vt/vt_ioctl.c:265
 tty_ioctl+0xee4/0x15c0 drivers/tty/tty_io.c:2656
 vfs_ioctl fs/ioctl.c:48 [inline]
 ksys_ioctl fs/ioctl.c:753 [inline]
 __do_sys_ioctl fs/ioctl.c:762 [inline]
 __se_sys_ioctl+0xf9/0x160 fs/ioctl.c:760
 do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 3929:
 save_stack mm/kasan/common.c:48 [inline]
 set_track mm/kasan/common.c:56 [inline]
 kasan_set_free_info mm/kasan/common.c:316 [inline]
 __kasan_slab_free+0x114/0x170 mm/kasan/common.c:455
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x10a/0x220 mm/slab.c:3757
 skb_release_all net/core/skbuff.c:664 [inline]
 __kfree_skb+0x56/0x1c0 net/core/skbuff.c:678
 skb_free_datagram+0x24/0xd0 net/core/datagram.c:325
 unix_dgram_recvmsg+0xa73/0xf00 net/unix/af_unix.c:2188
 ____sys_recvmsg+0x24a/0x510 include/linux/uio.h:235
 ___sys_recvmsg net/socket.c:2617 [inline]
 __sys_recvmsg+0x23b/0x7e0 net/socket.c:2651
 do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff88809e00c800
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 304 bytes inside of
 512-byte region [ffff88809e00c800, ffff88809e00ca00)
The buggy address belongs to the page:
page:ffffea0002780300 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88809e00cc00
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00023e6488 ffffea0001715848 ffff8880aa400a80
raw: ffff88809e00cc00 ffff88809e00c000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809e00c800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88809e00c880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88809e00c900: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                     ^
 ffff88809e00c980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88809e00ca00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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