================================================================== 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+0xc74/0xe10 drivers/video/fbdev/core/bitblit.c:185 Read of size 1 at addr ffff88808618881e by task syz-executor.0/9208 CPU: 0 PID: 9208 Comm: syz-executor.0 Not tainted 4.19.119-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 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 __fb_pad_aligned_buffer include/linux/fb.h:674 [inline] bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline] bit_putcs+0xc74/0xe10 drivers/video/fbdev/core/bitblit.c:185 fbcon_putcs+0x434/0x4f0 drivers/video/fbdev/core/fbcon.c:1323 do_update_region+0x2cf/0x630 drivers/tty/vt/vt.c:668 redraw_screen+0x5e1/0x870 drivers/tty/vt/vt.c:1026 vc_do_resize+0x108e/0x1380 drivers/tty/vt/vt.c:1312 vt_ioctl+0x1fa2/0x2500 drivers/tty/vt/vt_ioctl.c:901 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 RIP: 0033:0x45c829 Code: 0d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f26dcbe4c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004f2640 RCX: 000000000045c829 RDX: 0000000020000000 RSI: 000000000000560a RDI: 0000000000000003 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000066c R14: 00000000004c9401 R15: 00007f26dcbe56d4 Allocated by task 8363: 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_node mm/slab.c:3689 [inline] __kmalloc_node_track_caller+0x4c/0x70 mm/slab.c:3703 __kmalloc_reserve.isra.0+0x39/0xe0 net/core/skbuff.c:137 __alloc_skb+0xef/0x5b0 net/core/skbuff.c:205 alloc_skb include/linux/skbuff.h:995 [inline] alloc_skb_with_frags+0x92/0x560 net/core/skbuff.c:5303 sock_alloc_send_pskb+0x6b9/0x810 net/core/sock.c:2088 packet_alloc_skb net/packet/af_packet.c:2824 [inline] packet_snd net/packet/af_packet.c:2919 [inline] packet_sendmsg+0x1824/0x5f90 net/packet/af_packet.c:3001 sock_sendmsg_nosec net/socket.c:622 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:632 ___sys_sendmsg+0x3e2/0x920 net/socket.c:2115 __sys_sendmmsg+0x195/0x470 net/socket.c:2210 __do_sys_sendmmsg net/socket.c:2239 [inline] __se_sys_sendmmsg net/socket.c:2236 [inline] __x64_sys_sendmmsg+0x99/0x100 net/socket.c:2236 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 8363: 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 sit_tunnel_xmit net/ipv6/sit.c:1053 [inline] sit_tunnel_xmit+0x359/0x26ab net/ipv6/sit.c:1027 __netdev_start_xmit include/linux/netdevice.h:4314 [inline] netdev_start_xmit include/linux/netdevice.h:4323 [inline] dev_direct_xmit+0x333/0x600 net/core/dev.c:3912 packet_snd net/packet/af_packet.c:2976 [inline] packet_sendmsg+0x3835/0x5f90 net/packet/af_packet.c:3001 sock_sendmsg_nosec net/socket.c:622 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:632 ___sys_sendmsg+0x3e2/0x920 net/socket.c:2115 __sys_sendmmsg+0x195/0x470 net/socket.c:2210 __do_sys_sendmmsg net/socket.c:2239 [inline] __se_sys_sendmmsg net/socket.c:2236 [inline] __x64_sys_sendmmsg+0x99/0x100 net/socket.c:2236 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8880861887c0 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 94 bytes inside of 512-byte region [ffff8880861887c0, ffff8880861889c0) The buggy address belongs to the page: page:ffffea0002186200 count:1 mapcount:0 mapping:ffff88812c39c940 index:0xffff8880861887c0 flags: 0xfffe0000000100(slab) raw: 00fffe0000000100 ffffea000280e5c8 ffffea0002808dc8 ffff88812c39c940 raw: ffff8880861887c0 ffff888086188040 0000000100000004 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888086188700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888086188780: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb >ffff888086188800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888086188880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888086188900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== SELinux: security_context_str_to_sid(root) failed for (dev bpf, type bpf) errno=-22