================================================================== BUG: KASAN: use-after-free in memcpy include/linux/string.h:347 [inline] BUG: KASAN: use-after-free in soft_cursor+0x445/0xa40 drivers/video/fbdev/core/softcursor.c:70 Read of size 32 at addr ffff8880844046d0 by task syz-executor.5/24009 CPU: 0 PID: 24009 Comm: syz-executor.5 Not tainted 4.14.184-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 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 memcpy+0x20/0x50 mm/kasan/kasan.c:302 memcpy include/linux/string.h:347 [inline] soft_cursor+0x445/0xa40 drivers/video/fbdev/core/softcursor.c:70 bit_cursor+0x1072/0x1660 drivers/video/fbdev/core/bitblit.c:386 fbcon_cursor+0x4b1/0x690 drivers/video/fbdev/core/fbcon.c:1350 hide_cursor+0x7a/0x2a0 drivers/tty/vt/vt.c:590 redraw_screen+0x2a2/0x760 drivers/tty/vt/vt.c:680 fbcon_do_set_font+0x6bd/0x990 drivers/video/fbdev/core/fbcon.c:2564 fbcon_copy_font+0x125/0x190 drivers/video/fbdev/core/fbcon.c:2579 con_font_copy drivers/tty/vt/vt.c:4238 [inline] con_font_op+0x58b/0xf70 drivers/tty/vt/vt.c:4253 vt_ioctl+0x1376/0x1f20 drivers/tty/vt/vt_ioctl.c:980 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 RIP: 0033:0x45ca59 RSP: 002b:00007ff76c6b9c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004e7060 RCX: 000000000045ca59 RDX: 0000000020000500 RSI: 0000000000004b72 RDI: 0000000000000007 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000378 R14: 00000000004c60cb R15: 00007ff76c6ba6d4 Allocated by task 16509: 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_node mm/slab.c:3682 [inline] __kmalloc_node_track_caller+0x4c/0x70 mm/slab.c:3696 __kmalloc_reserve.isra.0+0x35/0xd0 net/core/skbuff.c:137 __alloc_skb+0xca/0x4c0 net/core/skbuff.c:205 alloc_skb include/linux/skbuff.h:980 [inline] kobject_uevent_env+0x6d1/0xc50 lib/kobject_uevent.c:479 netdev_queue_add_kobject net/core/net-sysfs.c:1347 [inline] netdev_queue_update_kobjects+0x283/0x350 net/core/net-sysfs.c:1364 register_queue_kobjects net/core/net-sysfs.c:1406 [inline] netdev_register_kobject+0x287/0x390 net/core/net-sysfs.c:1612 register_netdevice+0x811/0xca0 net/core/dev.c:7663 register_netdev+0x17/0x30 net/core/dev.c:7801 vti6_init_net+0x3e4/0x6a0 net/ipv6/ip6_vti.c:1129 ops_init+0xaa/0x3e0 net/core/net_namespace.c:118 setup_net+0x22f/0x500 net/core/net_namespace.c:295 copy_net_ns+0x19b/0x440 net/core/net_namespace.c:419 create_new_namespaces+0x375/0x730 kernel/nsproxy.c:107 unshare_nsproxy_namespaces+0xa5/0x1e0 kernel/nsproxy.c:206 SYSC_unshare kernel/fork.c:2391 [inline] SyS_unshare+0x2ea/0x740 kernel/fork.c:2341 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb Freed by task 16509: 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 netlink_broadcast_filtered+0x2b3/0x9d0 net/netlink/af_netlink.c:1489 kobject_uevent_env+0x819/0xc50 lib/kobject_uevent.c:495 netdev_queue_add_kobject net/core/net-sysfs.c:1347 [inline] netdev_queue_update_kobjects+0x283/0x350 net/core/net-sysfs.c:1364 register_queue_kobjects net/core/net-sysfs.c:1406 [inline] netdev_register_kobject+0x287/0x390 net/core/net-sysfs.c:1612 register_netdevice+0x811/0xca0 net/core/dev.c:7663 register_netdev+0x17/0x30 net/core/dev.c:7801 vti6_init_net+0x3e4/0x6a0 net/ipv6/ip6_vti.c:1129 ops_init+0xaa/0x3e0 net/core/net_namespace.c:118 setup_net+0x22f/0x500 net/core/net_namespace.c:295 copy_net_ns+0x19b/0x440 net/core/net_namespace.c:419 create_new_namespaces+0x375/0x730 kernel/nsproxy.c:107 unshare_nsproxy_namespaces+0xa5/0x1e0 kernel/nsproxy.c:206 SYSC_unshare kernel/fork.c:2391 [inline] SyS_unshare+0x2ea/0x740 kernel/fork.c:2341 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 ffff888084404540 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 400 bytes inside of 512-byte region [ffff888084404540, ffff888084404740) The buggy address belongs to the page: page:ffffea0002110100 count:1 mapcount:0 mapping:ffff888084404040 index:0xffff888084404cc0 flags: 0xfffe0000000100(slab) raw: 00fffe0000000100 ffff888084404040 ffff888084404cc0 0000000100000003 raw: ffffea00022e5aa0 ffffea000234b520 ffff8880aa800940 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888084404580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888084404600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888084404680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888084404700: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff888084404780: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00 ==================================================================