==================================================================
BUG: KASAN: slab-out-of-bounds in soft_cursor+0x96a/0xa50 drivers/video/fbdev/core/softcursor.c:61
Read of size 1 at addr ffff8880a8024e30 by task kworker/1:4/7401

CPU: 1 PID: 7401 Comm: kworker/1:4 Not tainted 4.14.198-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 mm/kasan/report.c:409 [inline]
 __asan_report_load1_noabort+0x68/0x70 mm/kasan/report.c:427
 soft_cursor+0x96a/0xa50 drivers/video/fbdev/core/softcursor.c:61
 bit_cursor+0x1056/0x1620 drivers/video/fbdev/core/bitblit.c:386
 fb_flashcursor+0x361/0x400 drivers/video/fbdev/core/fbcon.c:393
 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 27714:
 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:2642
 con_font_set drivers/tty/vt/vt.c:4190 [inline]
 con_font_op+0xb69/0xf60 drivers/tty/vt/vt.c:4255
 vt_ioctl+0xd91/0x1f50 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 24306:
 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_broadcast_filtered+0x2ab/0x9e0 net/netlink/af_netlink.c:1489
 kobject_uevent_env+0x851/0xcb0 lib/kobject_uevent.c:495
 rx_queue_add_kobject net/core/net-sysfs.c:931 [inline]
 net_rx_queue_update_kobjects+0xce/0x3e0 net/core/net-sysfs.c:953
 register_queue_kobjects net/core/net-sysfs.c:1401 [inline]
 netdev_register_kobject+0x26b/0x3a0 net/core/net-sysfs.c:1612
 register_netdevice+0x955/0xe40 net/core/dev.c:7660
 bond_newlink drivers/net/bonding/bond_netlink.c:453 [inline]
 bond_newlink+0x3d/0x80 drivers/net/bonding/bond_netlink.c:443
 rtnl_newlink+0xf88/0x1830 net/core/rtnetlink.c:2728
 rtnetlink_rcv_msg+0x3be/0xb10 net/core/rtnetlink.c:4316
 netlink_rcv_skb+0x125/0x390 net/netlink/af_netlink.c:2433
 netlink_unicast_kernel net/netlink/af_netlink.c:1287 [inline]
 netlink_unicast+0x437/0x610 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
 SYSC_sendto net/socket.c:1763 [inline]
 SyS_sendto+0x1c7/0x2c0 net/socket.c:1731
 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 ffff8880a8024d00
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 304 bytes inside of
 512-byte region [ffff8880a8024d00, ffff8880a8024f00)
The buggy address belongs to the page:
page:ffffea0002a00900 count:1 mapcount:0 mapping:ffff8880a8024080 index:0xffff8880a8024580
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffff8880a8024080 ffff8880a8024580 0000000100000002
raw: ffffea000281a2a0 ffffea000290e860 ffff88812fe50940 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a8024d00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880a8024d80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880a8024e00: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                     ^
 ffff8880a8024e80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880a8024f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================