kvm: vcpu 0: requested 128 ns lapic timer period limited to 500000 ns ================================================================== 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+0xb3a/0xcd0 drivers/video/fbdev/core/bitblit.c:185 Read of size 1 at addr ffff888064e10cb8 by task syz-executor.1/7118 CPU: 0 PID: 7118 Comm: syz-executor.1 Not tainted 4.14.173-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+0x13e/0x194 lib/dump_stack.c:58 print_address_description.cold+0x7c/0x1e2 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+0xa9/0x2ae mm/kasan/report.c:393 __fb_pad_aligned_buffer include/linux/fb.h:663 [inline] bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline] bit_putcs+0xb3a/0xcd0 drivers/video/fbdev/core/bitblit.c:185 fbcon_putcs+0x3c6/0x490 drivers/video/fbdev/core/fbcon.c:1298 con_flush drivers/tty/vt/vt.c:2186 [inline] do_con_write.part.0+0xc27/0x1a20 drivers/tty/vt/vt.c:2433 do_con_write drivers/tty/vt/vt.c:2205 [inline] con_write+0x33/0xc0 drivers/tty/vt/vt.c:2785 process_output_block drivers/tty/n_tty.c:595 [inline] n_tty_write+0x375/0xe30 drivers/tty/n_tty.c:2333 do_tty_write drivers/tty/tty_io.c:959 [inline] tty_write+0x3f0/0x700 drivers/tty/tty_io.c:1043 do_loop_readv_writev fs/read_write.c:698 [inline] do_loop_readv_writev fs/read_write.c:682 [inline] do_iter_write fs/read_write.c:956 [inline] do_iter_write+0x3d9/0x550 fs/read_write.c:935 vfs_writev+0x170/0x2a0 fs/read_write.c:999 do_writev+0xfc/0x2c0 fs/read_write.c:1034 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45c849 RSP: 002b:00007f66c9ee1c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 00007f66c9ee26d4 RCX: 000000000045c849 RDX: 0000000000000002 RSI: 0000000020000080 RDI: 0000000000000004 RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000d12 R14: 00000000004cb19d R15: 000000000076bf0c Allocated by task 16867: save_stack+0x32/0xa0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc mm/kasan/kasan.c:551 [inline] kasan_kmalloc+0xbf/0xe0 mm/kasan/kasan.c:529 __do_kmalloc_node mm/slab.c:3682 [inline] __kmalloc_node+0x4c/0x70 mm/slab.c:3689 kmalloc_node include/linux/slab.h:530 [inline] kvmalloc_node+0x46/0xd0 mm/util.c:397 kvmalloc include/linux/mm.h:531 [inline] xt_alloc_table_info+0x6a/0xe0 net/netfilter/x_tables.c:1062 do_replace net/ipv6/netfilter/ip6_tables.c:1146 [inline] do_ip6t_set_ctl+0x1b1/0x3a3 net/ipv6/netfilter/ip6_tables.c:1685 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline] nf_setsockopt+0x5f/0xb0 net/netfilter/nf_sockopt.c:115 ipv6_setsockopt net/ipv6/ipv6_sockglue.c:930 [inline] ipv6_setsockopt+0xfd/0x130 net/ipv6/ipv6_sockglue.c:914 tcp_setsockopt net/ipv4/tcp.c:2826 [inline] tcp_setsockopt+0x7b/0xc0 net/ipv4/tcp.c:2820 SYSC_setsockopt net/socket.c:1865 [inline] SyS_setsockopt+0x110/0x1e0 net/socket.c:1844 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Freed by task 16867: save_stack+0x32/0xa0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0x75/0xc0 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3496 [inline] kfree+0xcb/0x260 mm/slab.c:3815 kvfree+0x45/0x50 mm/util.c:416 __do_replace+0x3f6/0x580 net/ipv6/netfilter/ip6_tables.c:1107 do_replace net/ipv6/netfilter/ip6_tables.c:1161 [inline] do_ip6t_set_ctl+0x255/0x3a3 net/ipv6/netfilter/ip6_tables.c:1685 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline] nf_setsockopt+0x5f/0xb0 net/netfilter/nf_sockopt.c:115 ipv6_setsockopt net/ipv6/ipv6_sockglue.c:930 [inline] ipv6_setsockopt+0xfd/0x130 net/ipv6/ipv6_sockglue.c:914 tcp_setsockopt net/ipv4/tcp.c:2826 [inline] tcp_setsockopt+0x7b/0xc0 net/ipv4/tcp.c:2820 SYSC_setsockopt net/socket.c:1865 [inline] SyS_setsockopt+0x110/0x1e0 net/socket.c:1844 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 The buggy address belongs to the object at ffff888064e10940 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 888 bytes inside of 2048-byte region [ffff888064e10940, ffff888064e11140) The buggy address belongs to the page: page:ffffea0001938400 count:1 mapcount:0 mapping:ffff888064e100c0 index:0xffff888064e111c0 compound_mapcount: 0 flags: 0xfffe0000008100(slab|head) raw: 00fffe0000008100 ffff888064e100c0 ffff888064e111c0 0000000100000002 raw: ffffea00017f4520 ffffea00024e0720 ffff88812fe56c40 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888064e10b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888064e10c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888064e10c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888064e10d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888064e10d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================