netlink: 19 bytes leftover after parsing attributes in process `syz-executor.5'.
==================================================================
BUG: KASAN: slab-out-of-bounds in soft_cursor+0x95d/0xa40 drivers/video/fbdev/core/softcursor.c:61
Read of size 1 at addr ffff888028627bf0 by task kworker/1:4/7525

CPU: 1 PID: 7525 Comm: kworker/1:4 Not tainted 4.14.184-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+0x54/0x1dc mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report mm/kasan/report.c:409 [inline]
 kasan_report.cold+0xa9/0x2b9 mm/kasan/report.c:393
 soft_cursor+0x95d/0xa40 drivers/video/fbdev/core/softcursor.c:61
 bit_cursor+0x1072/0x1660 drivers/video/fbdev/core/bitblit.c:386
 fb_flashcursor+0x360/0x400 drivers/video/fbdev/core/fbcon.c:393
 process_one_work+0x7c0/0x14c0 kernel/workqueue.c:2116
 worker_thread+0x5d7/0x1080 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 20294:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc.part.0+0x4f/0xd0 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+0x2f8/0x7c0 drivers/video/fbdev/core/fbcon.c:2621
 con_font_set drivers/tty/vt/vt.c:4182 [inline]
 con_font_op+0xb73/0xf70 drivers/tty/vt/vt.c:4247
 vt_ioctl+0x736/0x1f20 drivers/tty/vt/vt_ioctl.c:928
 tty_ioctl+0x6c9/0x1220 drivers/tty/tty_io.c:2661
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x75a/0xfe0 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 7590:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xaf/0x190 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xcb/0x260 mm/slab.c:3815
 skb_free_head+0x83/0xa0 net/core/skbuff.c:554
 skb_release_data+0x57e/0x7d0 net/core/skbuff.c:574
 skb_release_all+0x46/0x60 net/core/skbuff.c:631
 __kfree_skb net/core/skbuff.c:645 [inline]
 consume_skb+0xa7/0x330 net/core/skbuff.c:705
 arp_process+0x9a2/0x2130 net/ipv4/arp.c:919
 NF_HOOK include/linux/netfilter.h:250 [inline]
 arp_rcv net/ipv4/arp.c:965 [inline]
 arp_rcv+0x381/0x710 net/ipv4/arp.c:940
 __netif_receive_skb_core+0x1e8e/0x2c10 net/core/dev.c:4478
 __netif_receive_skb+0x27/0x1a0 net/core/dev.c:4516
 process_backlog+0x20c/0x760 net/core/dev.c:5198
 napi_poll net/core/dev.c:5599 [inline]
 net_rx_action+0x456/0xe80 net/core/dev.c:5665
 __do_softirq+0x254/0x9bf kernel/softirq.c:288

The buggy address belongs to the object at ffff888028627ac0
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 304 bytes inside of
 512-byte region [ffff888028627ac0, ffff888028627cc0)
The buggy address belongs to the page:
page:ffffea0000a189c0 count:1 mapcount:0 mapping:ffff8880286270c0 index:0xffff888028627840
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffff8880286270c0 ffff888028627840 0000000100000002
raw: ffffea0000a632a0 ffffea0000a3c960 ffff8880aa800940 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888028627a80: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
 ffff888028627b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888028627b80: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
                                                             ^
 ffff888028627c00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888028627c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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