================================================================== BUG: KASAN: slab-out-of-bounds in __fb_pad_aligned_buffer include/linux/fb.h:663 [inline] BUG: KASAN: slab-out-of-bounds in bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline] BUG: KASAN: slab-out-of-bounds in bit_putcs+0xab7/0xc30 drivers/video/fbdev/core/bitblit.c:185 Read of size 1 at addr ffff8880a82d9f9a by task syz-executor.3/27867 CPU: 0 PID: 27867 Comm: syz-executor.3 Not tainted 4.14.198-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 invert_screen+0x294/0x550 drivers/tty/vt/vt.c:490 highlight drivers/tty/vt/selection.c:55 [inline] clear_selection drivers/tty/vt/selection.c:81 [inline] clear_selection+0x48/0x60 drivers/tty/vt/selection.c:77 hide_cursor+0x158/0x2a0 drivers/tty/vt/vt.c:588 do_con_write+0x102b/0x19b0 drivers/tty/vt/vt.c:2251 con_write+0x21/0xa0 drivers/tty/vt/vt.c:2805 process_output_block drivers/tty/n_tty.c:595 [inline] n_tty_write+0x352/0xda0 drivers/tty/n_tty.c:2333 do_tty_write drivers/tty/tty_io.c:959 [inline] tty_write+0x410/0x740 drivers/tty/tty_io.c:1043 __vfs_write+0xe4/0x630 fs/read_write.c:480 vfs_write+0x17f/0x4d0 fs/read_write.c:544 SYSC_write fs/read_write.c:590 [inline] SyS_write+0xf2/0x210 fs/read_write.c:582 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45e179 RSP: 002b:00007fa69eaacc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00000000000393c0 RCX: 000000000045e179 RDX: 0000000000001006 RSI: 0000000020001440 RDI: 0000000000000005 RBP: 000000000118cf80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c R13: 00007ffd9853564f R14: 00007fa69eaad9c0 R15: 000000000118cf4c Allocated by task 27671: 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 mm/slab.c:3720 [inline] __kmalloc+0x15a/0x400 mm/slab.c:3729 kmalloc include/linux/slab.h:493 [inline] fbcon_set_font+0x2fb/0x7c0 drivers/video/fbdev/core/fbcon.c:2642 con_font_set drivers/tty/vt/vt.c:4190 [inline] con_font_op+0xb69/0xf60 drivers/tty/vt/vt.c:4255 vt_ioctl+0xd91/0x1f50 drivers/tty/vt/vt_ioctl.c:938 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 Freed by task 1: 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] consume_skb+0xe0/0x380 net/core/skbuff.c:705 skb_free_datagram+0x16/0xe0 net/core/datagram.c:331 netlink_recvmsg+0x5c1/0xda0 net/netlink/af_netlink.c:1957 sock_recvmsg_nosec net/socket.c:819 [inline] sock_recvmsg net/socket.c:826 [inline] sock_recvmsg+0xc0/0x100 net/socket.c:822 ___sys_recvmsg+0x20b/0x4d0 net/socket.c:2221 __sys_recvmsg+0xa0/0x120 net/socket.c:2266 SYSC_recvmsg net/socket.c:2278 [inline] SyS_recvmsg+0x27/0x40 net/socket.c:2273 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 ffff8880a82d9b40 which belongs to the cache kmalloc-1024 of size 1024 The buggy address is located 90 bytes to the right of 1024-byte region [ffff8880a82d9b40, ffff8880a82d9f40) The buggy address belongs to the page: page:ffffea0002a0b600 count:1 mapcount:0 mapping:ffff8880a82d8040 index:0xffff8880a82d96c0 compound_mapcount: 0 flags: 0xfffe0000008100(slab|head) raw: 00fffe0000008100 ffff8880a82d8040 ffff8880a82d96c0 0000000100000002 raw: ffffea00014b9da0 ffffea000236a2a0 ffff88812fe50ac0 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a82d9e80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880a82d9f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880a82d9f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff8880a82da000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8880a82da080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ================================================================== XFS (loop2): device supports 512 byte sectors (not 0)