netlink: 24 bytes leftover after parsing attributes in process `syz-executor.5'.
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BUG: KASAN: slab-out-of-bounds in soft_cursor+0x95a/0xa20 drivers/video/fbdev/core/softcursor.c:61
Read of size 1 at addr ffff8880a66e98f0 by task kworker/1:0/20094

CPU: 1 PID: 20094 Comm: kworker/1:0 Not tainted 4.19.120-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+0x188/0x20d lib/dump_stack.c:118
 print_address_description.cold+0x7c/0x212 mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report mm/kasan/report.c:412 [inline]
 kasan_report.cold+0x88/0x2b9 mm/kasan/report.c:396
 soft_cursor+0x95a/0xa20 drivers/video/fbdev/core/softcursor.c:61
 bit_cursor+0x1230/0x1900 drivers/video/fbdev/core/bitblit.c:386
 fb_flashcursor+0x396/0x440 drivers/video/fbdev/core/fbcon.c:399
 process_one_work+0x91f/0x1640 kernel/workqueue.c:2155
 worker_thread+0x96/0xe20 kernel/workqueue.c:2298
 kthread+0x34a/0x420 kernel/kthread.c:246
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415

Allocated by task 15677:
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc mm/kasan/kasan.c:553 [inline]
 kasan_kmalloc+0xbf/0xe0 mm/kasan/kasan.c:531
 __do_kmalloc mm/slab.c:3727 [inline]
 __kmalloc+0x15b/0x770 mm/slab.c:3736
 kmalloc include/linux/slab.h:520 [inline]
 fbcon_set_font+0x331/0x870 drivers/video/fbdev/core/fbcon.c:2644
 con_font_set drivers/tty/vt/vt.c:4524 [inline]
 con_font_op+0xd3e/0x1130 drivers/tty/vt/vt.c:4589
 vt_ioctl+0xcd0/0x2500 drivers/tty/vt/vt_ioctl.c:928
 tty_ioctl+0x7a1/0x1420 drivers/tty/tty_io.c:2669
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0xcda/0x12e0 fs/ioctl.c:688
 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
 __do_sys_ioctl fs/ioctl.c:712 [inline]
 __se_sys_ioctl fs/ioctl.c:710 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 15280:
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0xf7/0x140 mm/kasan/kasan.c:521
 __cache_free mm/slab.c:3503 [inline]
 kfree+0xce/0x220 mm/slab.c:3822
 skb_free_head+0x91/0xb0 net/core/skbuff.c:554
 skb_release_data+0x600/0x8c0 net/core/skbuff.c:574
 skb_release_all+0x46/0x60 net/core/skbuff.c:631
 __kfree_skb net/core/skbuff.c:645 [inline]
 kfree_skb net/core/skbuff.c:663 [inline]
 kfree_skb+0xe1/0x390 net/core/skbuff.c:657
 skb_queue_purge+0x14/0x30 net/core/skbuff.c:2858
 pppoe_release+0x3f5/0x620 drivers/net/ppp/pppoe.c:606
 __sock_release+0xcd/0x2a0 net/socket.c:579
 sock_close+0x15/0x20 net/socket.c:1140
 __fput+0x2cd/0x890 fs/file_table.c:278
 task_work_run+0x13f/0x1b0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:193 [inline]
 exit_to_usermode_loop+0x25a/0x2b0 arch/x86/entry/common.c:167
 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:271 [inline]
 do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8880a66e97c0
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 304 bytes inside of
 512-byte region [ffff8880a66e97c0, ffff8880a66e99c0)
The buggy address belongs to the page:
page:ffffea000299ba40 count:1 mapcount:0 mapping:ffff88812c39c940 index:0x0
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffffea00017c1588 ffffea000281c9c8 ffff88812c39c940
raw: 0000000000000000 ffff8880a66e9040 0000000100000006 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a66e9780: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
 ffff8880a66e9800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880a66e9880: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
                                                             ^
 ffff8880a66e9900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880a66e9980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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