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BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:376 [inline]
BUG: KASAN: slab-out-of-bounds in soft_cursor+0x442/0xa50 drivers/video/fbdev/core/softcursor.c:70
Read of size 5 at addr ffff8880b4517467 by task kworker/1:4/9191

CPU: 1 PID: 9191 Comm: kworker/1:4 Not tainted 4.14.232-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+0x1b2/0x281 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252
 kasan_report_error.cold+0x8a/0x191 mm/kasan/report.c:351
 kasan_report+0x6f/0x80 mm/kasan/report.c:409
 memcpy+0x20/0x50 mm/kasan/kasan.c:302
 memcpy include/linux/string.h:376 [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 9577:
 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:2459
 con_font_set drivers/tty/vt/vt.c:4190 [inline]
 con_font_op+0x9e8/0xdb0 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 7981:
 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:563 [inline]
 skb_release_data+0x5f6/0x820 net/core/skbuff.c:583
 skb_release_all net/core/skbuff.c:640 [inline]
 __kfree_skb net/core/skbuff.c:654 [inline]
 consume_skb+0xe0/0x380 net/core/skbuff.c:714
 __dev_kfree_skb_any+0x7a/0xa0 net/core/dev.c:2529
 dev_consume_skb_any include/linux/netdevice.h:3286 [inline]
 free_old_xmit_skbs+0x184/0x2c0 drivers/net/virtio_net.c:1137
 start_xmit+0x148/0x14f0 drivers/net/virtio_net.c:1299
 __netdev_start_xmit include/linux/netdevice.h:4051 [inline]
 netdev_start_xmit include/linux/netdevice.h:4060 [inline]
 xmit_one net/core/dev.c:3005 [inline]
 dev_hard_start_xmit+0x188/0x890 net/core/dev.c:3021
 sch_direct_xmit+0x251/0x500 net/sched/sch_generic.c:186
 __dev_xmit_skb net/core/dev.c:3214 [inline]
 __dev_queue_xmit+0x1ab0/0x2480 net/core/dev.c:3489
 neigh_hh_output include/net/neighbour.h:490 [inline]
 neigh_output include/net/neighbour.h:498 [inline]
 ip_finish_output2+0x9db/0x1340 net/ipv4/ip_output.c:230
 ip_finish_output+0x37c/0xc50 net/ipv4/ip_output.c:318
 NF_HOOK_COND include/linux/netfilter.h:239 [inline]
 ip_output+0x1cd/0x510 net/ipv4/ip_output.c:406
 dst_output include/net/dst.h:470 [inline]
 ip_local_out+0x93/0x170 net/ipv4/ip_output.c:125
 ip_queue_xmit+0x7d3/0x1a80 net/ipv4/ip_output.c:505
 __tcp_transmit_skb+0x17e2/0x2cb0 net/ipv4/tcp_output.c:1133
 __tcp_send_ack.part.0+0x399/0x580 net/ipv4/tcp_output.c:3648
 __tcp_send_ack net/ipv4/tcp_output.c:3654 [inline]
 tcp_send_ack+0x6f/0x90 net/ipv4/tcp_output.c:3654
 tcp_cleanup_rbuf+0x3c5/0x4a0 net/ipv4/tcp.c:1592
 tcp_recvmsg+0x665/0x1d50 net/ipv4/tcp.c:2011
 inet_recvmsg+0xef/0x4d0 net/ipv4/af_inet.c:793
 sock_recvmsg_nosec net/socket.c:819 [inline]
 sock_recvmsg net/socket.c:826 [inline]
 sock_recvmsg net/socket.c:822 [inline]
 sock_read_iter+0x2be/0x3f0 net/socket.c:903
 call_read_iter include/linux/fs.h:1772 [inline]
 new_sync_read fs/read_write.c:401 [inline]
 __vfs_read+0x449/0x620 fs/read_write.c:413
 vfs_read+0x139/0x340 fs/read_write.c:447
 SYSC_read fs/read_write.c:574 [inline]
 SyS_read+0xf2/0x210 fs/read_write.c:567
 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 ffff8880b4517240
 which belongs to the cache kmalloc-1024 of size 1024
The buggy address is located 551 bytes inside of
 1024-byte region [ffff8880b4517240, ffff8880b4517640)
The buggy address belongs to the page:
page:ffffea0002d14580 count:1 mapcount:0 mapping:ffff8880b4516040 index:0xffff8880b4516040 compound_mapcount: 0
flags: 0xfff00000008100(slab|head)
raw: 00fff00000008100 ffff8880b4516040 ffff8880b4516040 0000000100000005
raw: ffffea00025b9e20 ffffea000243ca20 ffff88813fe80ac0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880b4517300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880b4517380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880b4517400: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
                                                       ^
 ffff8880b4517480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880b4517500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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