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BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:372 [inline]
BUG: KASAN: slab-out-of-bounds in soft_cursor+0x442/0xa50 drivers/video/fbdev/core/softcursor.c:70
Read of size 9 at addr ffff88809c93ddf0 by task kworker/0:2/4629

CPU: 0 PID: 4629 Comm: kworker/0:2 Not tainted 4.14.213-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:17 [inline]
 dump_stack+0x1b2/0x283 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252
 kasan_report_error.cold+0x8a/0x194 mm/kasan/report.c:351
 kasan_report+0x6f/0x7b mm/kasan/report.c:409
 memcpy+0x20/0x50 mm/kasan/kasan.c:302
 memcpy include/linux/string.h:372 [inline]
 soft_cursor+0x442/0xa50 drivers/video/fbdev/core/softcursor.c:70
 bit_cursor+0xf7a/0x1580 drivers/video/fbdev/core/bitblit.c:377
 fb_flashcursor+0x356/0x3f0 drivers/video/fbdev/core/fbcon.c:373
 process_one_work+0x793/0x14a0 kernel/workqueue.c:2116
 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2250
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404

Allocated by task 11279:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551
 __do_kmalloc mm/slab.c:3720 [inline]
 __kmalloc+0x15a/0x400 mm/slab.c:3729
 kmalloc include/linux/slab.h:493 [inline]
 fbcon_set_font+0x2fb/0x7c0 drivers/video/fbdev/core/fbcon.c:2456
 con_font_set drivers/tty/vt/vt.c:4190 [inline]
 con_font_op+0x9e2/0xd90 drivers/tty/vt/vt.c:4234
 vt_ioctl+0xd5d/0x1d50 drivers/tty/vt/vt_ioctl.c:938
 tty_ioctl+0x50f/0x13c0 drivers/tty/tty_io.c:2661
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x75a/0xff0 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 10318:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xc3/0x1a0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xc9/0x250 mm/slab.c:3815
 skb_free_head net/core/skbuff.c:554 [inline]
 skb_release_data+0x5f6/0x820 net/core/skbuff.c:574
 skb_release_all net/core/skbuff.c:631 [inline]
 __kfree_skb net/core/skbuff.c:645 [inline]
 consume_skb+0xe0/0x380 net/core/skbuff.c:705
 netlink_unicast_kernel net/netlink/af_netlink.c:1288 [inline]
 netlink_unicast+0x43f/0x610 net/netlink/af_netlink.c:1313
 netlink_sendmsg+0x62e/0xb80 net/netlink/af_netlink.c:1878
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xb5/0x100 net/socket.c:656
 ___sys_sendmsg+0x6c8/0x800 net/socket.c:2062
 __sys_sendmsg+0xa3/0x120 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x27/0x40 net/socket.c:2103
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

The buggy address belongs to the object at ffff88809c93dcc0
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 304 bytes inside of
 512-byte region [ffff88809c93dcc0, ffff88809c93dec0)
The buggy address belongs to the page:
page:ffffea0002724f40 count:1 mapcount:0 mapping:ffff88809c93d040 index:0xffff88809c93d540
flags: 0xfff00000000100(slab)
raw: 00fff00000000100 ffff88809c93d040 ffff88809c93d540 0000000100000004
raw: ffffea000289f360 ffffea000274a7a0 ffff88813fe80940 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809c93dc80: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
 ffff88809c93dd00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88809c93dd80: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
                                                             ^
 ffff88809c93de00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88809c93de80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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