netlink: 20 bytes leftover after parsing attributes in process `syz-executor.2'. audit: type=1800 audit(1598367460.154:797): pid=21147 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="collect_data" cause="failed(directio)" comm="syz-executor.0" name="bus" dev="sda1" ino=16500 res=0 netlink: 20 bytes leftover after parsing attributes in process `syz-executor.4'. ================================================================== BUG: KASAN: use-after-free in __fb_pad_aligned_buffer include/linux/fb.h:663 [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+0xab7/0xc30 drivers/video/fbdev/core/bitblit.c:185 Read of size 1 at addr ffff88809fe8a9b5 by task syz-executor.1/21146 CPU: 0 PID: 21146 Comm: syz-executor.1 Not tainted 4.14.194-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+0x54/0x1d3 mm/kasan/report.c:252 kasan_report_error.cold+0x8a/0x194 mm/kasan/report.c:351 kasan_report mm/kasan/report.c:409 [inline] __asan_report_load1_noabort+0x68/0x70 mm/kasan/report.c:427 __fb_pad_aligned_buffer include/linux/fb.h:663 [inline] bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline] bit_putcs+0xab7/0xc30 drivers/video/fbdev/core/bitblit.c:185 fbcon_putcs+0x2fe/0x480 drivers/video/fbdev/core/fbcon.c:1301 do_update_region+0x34b/0x5b0 drivers/tty/vt/vt.c:373 redraw_screen+0x56e/0x790 drivers/tty/vt/vt.c:705 vc_do_resize+0xc20/0xe30 drivers/tty/vt/vt.c:973 vt_ioctl+0x19f7/0x1ea0 drivers/tty/vt/vt_ioctl.c:901 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 RIP: 0033:0x45d579 RSP: 002b:00007f499a13bc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000001cfc0 RCX: 000000000045d579 RDX: 0000000020000a00 RSI: 000000000000560a RDI: 0000000000000004 RBP: 000000000118cf80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c R13: 00007ffd1566c73f R14: 00007f499a13c9c0 R15: 000000000118cf4c Allocated by task 18365: 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_node mm/slab.c:3682 [inline] __kmalloc_node_track_caller+0x4c/0x70 mm/slab.c:3696 __kmalloc_reserve net/core/skbuff.c:137 [inline] __alloc_skb+0x96/0x510 net/core/skbuff.c:205 alloc_skb include/linux/skbuff.h:980 [inline] alloc_skb_with_frags+0x85/0x500 net/core/skbuff.c:5228 sock_alloc_send_pskb+0x577/0x6d0 net/core/sock.c:2083 __ip6_append_data.isra.0+0x161f/0x2860 net/ipv6/ip6_output.c:1419 ip6_make_skb+0x211/0x3c0 net/ipv6/ip6_output.c:1768 udpv6_sendmsg+0x1e02/0x2530 net/ipv6/udp.c:1347 inet_sendmsg+0x11a/0x4e0 net/ipv4/af_inet.c:762 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xb5/0x100 net/socket.c:656 ___sys_sendmsg+0x326/0x800 net/socket.c:2062 __sys_sendmmsg+0x129/0x330 net/socket.c:2152 SYSC_sendmmsg net/socket.c:2183 [inline] SyS_sendmmsg+0x2f/0x50 net/socket.c:2178 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb Freed by task 18365: 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:554 [inline] skb_release_data+0x5f6/0x820 net/core/skbuff.c:574 skb_release_all net/core/skbuff.c:631 [inline] __kfree_skb net/core/skbuff.c:645 [inline] kfree_skb+0xe7/0x390 net/core/skbuff.c:663 ip6_finish_output2+0xef3/0x1f10 net/ipv6/ip6_output.c:101 ip6_finish_output+0x60c/0xaf0 net/ipv6/ip6_output.c:154 NF_HOOK_COND include/linux/netfilter.h:239 [inline] ip6_output+0x1c5/0x660 net/ipv6/ip6_output.c:171 dst_output include/net/dst.h:470 [inline] ip6_local_out+0x93/0x170 net/ipv6/output_core.c:178 ip6_send_skb+0x9b/0x2f0 net/ipv6/ip6_output.c:1688 udp_v6_send_skb+0x4e8/0xe80 net/ipv6/udp.c:1081 udpv6_sendmsg+0x1e3b/0x2530 net/ipv6/udp.c:1353 inet_sendmsg+0x11a/0x4e0 net/ipv4/af_inet.c:762 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xb5/0x100 net/socket.c:656 ___sys_sendmsg+0x326/0x800 net/socket.c:2062 __sys_sendmmsg+0x129/0x330 net/socket.c:2152 SYSC_sendmmsg net/socket.c:2183 [inline] SyS_sendmmsg+0x2f/0x50 net/socket.c:2178 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 ffff88809fe8a940 which belongs to the cache kmalloc-1024 of size 1024 The buggy address is located 117 bytes inside of 1024-byte region [ffff88809fe8a940, ffff88809fe8ad40) The buggy address belongs to the page: page:ffffea00027fa280 count:1 mapcount:0 mapping:ffff88809fe8a040 index:0xffff88809fe8a040 compound_mapcount: 0 flags: 0xfffe0000008100(slab|head) raw: 00fffe0000008100 ffff88809fe8a040 ffff88809fe8a040 0000000100000001 raw: ffffea000236a2a0 ffffea00027e6820 ffff88812fe52ac0 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88809fe8a880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88809fe8a900: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb >ffff88809fe8a980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88809fe8aa00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88809fe8aa80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================