================================================================== BUG: KASAN: use-after-free in __fb_pad_aligned_buffer include/linux/fb.h:674 [inline] BUG: KASAN: use-after-free in bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline] BUG: KASAN: use-after-free in bit_putcs+0xd5d/0xf10 drivers/video/fbdev/core/bitblit.c:185 Read of size 1 at addr ffff888057f4a6d0 by task kworker/0:2/26569 CPU: 0 PID: 26569 Comm: kworker/0:2 Not tainted 4.19.88-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events console_callback Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 print_address_description.cold+0x7c/0x20d 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+0x8c/0x2ba mm/kasan/report.c:396 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:430 __fb_pad_aligned_buffer include/linux/fb.h:674 [inline] bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline] bit_putcs+0xd5d/0xf10 drivers/video/fbdev/core/bitblit.c:185 fbcon_putcs+0x42b/0x4f0 drivers/video/fbdev/core/fbcon.c:1320 do_update_region+0x42b/0x6f0 drivers/tty/vt/vt.c:677 redraw_screen+0x602/0x8e0 drivers/tty/vt/vt.c:1013 complete_change_console+0x105/0x3a0 drivers/tty/vt/vt_ioctl.c:1277 change_console+0x19b/0x2c0 drivers/tty/vt/vt_ioctl.c:1402 console_callback+0x3a1/0x400 drivers/tty/vt/vt.c:2800 process_one_work+0x989/0x1750 kernel/workqueue.c:2153 worker_thread+0x98/0xe40 kernel/workqueue.c:2296 kthread+0x354/0x420 kernel/kthread.c:246 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Allocated by task 30377: save_stack+0x45/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc mm/kasan/kasan.c:553 [inline] kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:531 __do_kmalloc_node mm/slab.c:3689 [inline] __kmalloc_node_track_caller+0x51/0x80 mm/slab.c:3703 __kmalloc_reserve.isra.0+0x40/0xf0 net/core/skbuff.c:137 __alloc_skb+0x10b/0x5f0 net/core/skbuff.c:205 alloc_skb include/linux/skbuff.h:995 [inline] alloc_uevent_skb+0x83/0x1e2 lib/kobject_uevent.c:288 uevent_net_broadcast_tagged lib/kobject_uevent.c:349 [inline] kobject_uevent_net_broadcast lib/kobject_uevent.c:409 [inline] kobject_uevent_env+0xbd8/0x101f lib/kobject_uevent.c:590 kobject_uevent+0x20/0x26 lib/kobject_uevent.c:639 netdev_queue_add_kobject net/core/net-sysfs.c:1486 [inline] netdev_queue_update_kobjects+0x2ff/0x3d0 net/core/net-sysfs.c:1500 register_queue_kobjects net/core/net-sysfs.c:1542 [inline] netdev_register_kobject+0x29f/0x3b0 net/core/net-sysfs.c:1760 register_netdevice+0x875/0xff0 net/core/dev.c:8546 __ip_tunnel_create+0x36b/0x530 net/ipv4/ip_tunnel.c:282 ip_tunnel_init_net+0x375/0x9e0 net/ipv4/ip_tunnel.c:1026 ipgre_tap_init_net+0x2a/0x30 net/ipv4/ip_gre.c:1656 ops_init+0xb3/0x410 net/core/net_namespace.c:129 setup_net+0x2d3/0x740 net/core/net_namespace.c:315 copy_net_ns+0x1df/0x33c net/core/net_namespace.c:438 create_new_namespaces+0x400/0x7b0 kernel/nsproxy.c:107 unshare_nsproxy_namespaces+0xc2/0x200 kernel/nsproxy.c:206 ksys_unshare+0x440/0x980 kernel/fork.c:2520 __do_sys_unshare kernel/fork.c:2588 [inline] __se_sys_unshare kernel/fork.c:2586 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:2586 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 30377: save_stack+0x45/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3503 [inline] kfree+0xcf/0x220 mm/slab.c:3822 skb_free_head+0x99/0xc0 net/core/skbuff.c:554 skb_release_data+0x619/0x8d0 net/core/skbuff.c:574 skb_release_all+0x4d/0x60 net/core/skbuff.c:631 __kfree_skb net/core/skbuff.c:645 [inline] consume_skb net/core/skbuff.c:705 [inline] consume_skb+0xe2/0x390 net/core/skbuff.c:699 netlink_broadcast_filtered+0x316/0xb30 net/netlink/af_netlink.c:1519 netlink_broadcast+0x3a/0x50 net/netlink/af_netlink.c:1541 uevent_net_broadcast_tagged lib/kobject_uevent.c:370 [inline] kobject_uevent_net_broadcast lib/kobject_uevent.c:409 [inline] kobject_uevent_env+0xcbf/0x101f lib/kobject_uevent.c:590 kobject_uevent+0x20/0x26 lib/kobject_uevent.c:639 netdev_queue_add_kobject net/core/net-sysfs.c:1486 [inline] netdev_queue_update_kobjects+0x2ff/0x3d0 net/core/net-sysfs.c:1500 register_queue_kobjects net/core/net-sysfs.c:1542 [inline] netdev_register_kobject+0x29f/0x3b0 net/core/net-sysfs.c:1760 register_netdevice+0x875/0xff0 net/core/dev.c:8546 __ip_tunnel_create+0x36b/0x530 net/ipv4/ip_tunnel.c:282 ip_tunnel_init_net+0x375/0x9e0 net/ipv4/ip_tunnel.c:1026 ipgre_tap_init_net+0x2a/0x30 net/ipv4/ip_gre.c:1656 ops_init+0xb3/0x410 net/core/net_namespace.c:129 setup_net+0x2d3/0x740 net/core/net_namespace.c:315 copy_net_ns+0x1df/0x33c net/core/net_namespace.c:438 create_new_namespaces+0x400/0x7b0 kernel/nsproxy.c:107 unshare_nsproxy_namespaces+0xc2/0x200 kernel/nsproxy.c:206 ksys_unshare+0x440/0x980 kernel/fork.c:2520 __do_sys_unshare kernel/fork.c:2588 [inline] __se_sys_unshare kernel/fork.c:2586 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:2586 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff888057f4a500 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 464 bytes inside of 512-byte region [ffff888057f4a500, ffff888057f4a700) The buggy address belongs to the page: page:ffffea00015fd280 count:1 mapcount:0 mapping:ffff88812c31c940 index:0x0 flags: 0xfffe0000000100(slab) raw: 00fffe0000000100 ffffea00027ca8c8 ffffea000210f908 ffff88812c31c940 raw: 0000000000000000 ffff888057f4a000 0000000100000006 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888057f4a580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888057f4a600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888057f4a680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888057f4a700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888057f4a780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================