================================================================== 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 15 at addr ffff8880b4533c70 by task kworker/1:3/4645 CPU: 1 PID: 4645 Comm: kworker/1:3 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 7955: 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 6216: 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 skb_free_datagram+0x16/0xe0 net/core/datagram.c:331 netlink_recvmsg+0x5c1/0xda0 net/netlink/af_netlink.c:1957 sock_recvmsg_nosec net/socket.c:819 [inline] sock_recvmsg net/socket.c:826 [inline] sock_recvmsg+0xc0/0x100 net/socket.c:822 ___sys_recvmsg+0x20b/0x4d0 net/socket.c:2221 __sys_recvmsg+0xa0/0x120 net/socket.c:2266 SYSC_recvmsg net/socket.c:2278 [inline] SyS_recvmsg+0x27/0x40 net/socket.c:2273 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 ffff8880b4533a80 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 496 bytes inside of 512-byte region [ffff8880b4533a80, ffff8880b4533c80) The buggy address belongs to the page: page:ffffea0002d14cc0 count:1 mapcount:0 mapping:ffff8880b4533080 index:0x0 flags: 0xfff00000000100(slab) raw: 00fff00000000100 ffff8880b4533080 0000000000000000 0000000100000006 raw: ffffea0002d29820 ffffea0002595720 ffff88813fe80940 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880b4533b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8880b4533b80: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880b4533c00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff8880b4533c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880b4533d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================