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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 8 at addr ffff8880a6fb7510 by task kworker/0:1/25659

CPU: 0 PID: 25659 Comm: kworker/0:1 Not tainted 5.8.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_power_efficient fb_flashcursor
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
 fb_flashcursor+0x725/0xa10 drivers/video/fbdev/core/fbcon.c:417
 process_one_work+0x789/0xfc0 kernel/workqueue.c:2269
 worker_thread+0xaa4/0x1460 kernel/workqueue.c:2415
 kthread+0x37e/0x3a0 drivers/block/aoe/aoecmd.c:1234
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

Allocated by task 20176:
 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 3892:
 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
 netlink_recvmsg+0x553/0xfe0 net/netlink/af_netlink.c:1997
 ____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 ffff8880a6fb7400
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 272 bytes inside of
 512-byte region [ffff8880a6fb7400, ffff8880a6fb7600)
The buggy address belongs to the page:
page:ffffea00029bedc0 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8880a6fb7800
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea000226fb88 ffffea0002a28888 ffff8880aa400a80
raw: ffff8880a6fb7800 ffff8880a6fb7000 0000000100000003 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a6fb7400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880a6fb7480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880a6fb7500: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                         ^
 ffff8880a6fb7580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880a6fb7600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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