netlink: 24 bytes leftover after parsing attributes in process `syz-executor.3'. ================================================================== 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+0xa8a/0xc00 drivers/video/fbdev/core/bitblit.c:185 Read of size 1 at addr ffff8880a8099e56 by task syz-executor.0/20548 CPU: 1 PID: 20548 Comm: syz-executor.0 Not tainted 4.14.184-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+0x54/0x1dc 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+0xa9/0x2b9 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+0xa8a/0xc00 drivers/video/fbdev/core/bitblit.c:185 fbcon_putcs+0x3bb/0x480 drivers/video/fbdev/core/fbcon.c:1301 do_update_region+0x282/0x5b0 drivers/tty/vt/vt.c:363 redraw_screen+0x562/0x760 drivers/tty/vt/vt.c:705 fbcon_modechanged+0x552/0x800 drivers/video/fbdev/core/fbcon.c:2949 fbcon_event_notify+0x11a/0x1750 drivers/video/fbdev/core/fbcon.c:3302 notifier_call_chain+0x107/0x1a0 kernel/notifier.c:93 __blocking_notifier_call_chain kernel/notifier.c:317 [inline] __blocking_notifier_call_chain kernel/notifier.c:304 [inline] blocking_notifier_call_chain kernel/notifier.c:328 [inline] blocking_notifier_call_chain+0x79/0x90 kernel/notifier.c:325 fb_set_var+0xaad/0xc70 drivers/video/fbdev/core/fbmem.c:1054 do_fb_ioctl+0x3cc/0x840 drivers/video/fbdev/core/fbmem.c:1127 fb_ioctl+0xda/0x120 drivers/video/fbdev/core/fbmem.c:1242 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xfe0 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: 0033:0x45ca59 RSP: 002b:00007f6800f9dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004e5020 RCX: 000000000045ca59 RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000006 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000002f7 R14: 00000000004c575e R15: 00007f6800f9e6d4 Allocated by task 12837: save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc.part.0+0x4f/0xd0 mm/kasan/kasan.c:551 kmem_cache_alloc_trace+0x14d/0x3f0 mm/slab.c:3618 kmalloc include/linux/slab.h:488 [inline] kzalloc include/linux/slab.h:661 [inline] wbt_init+0x4b/0x6a0 block/blk-wbt.c:719 wbt_enable_default block/blk-wbt.c:683 [inline] wbt_enable_default+0x9c/0xc0 block/blk-wbt.c:671 blk_register_queue+0x1a2/0x350 block/blk-sysfs.c:911 device_add_disk+0x932/0xd60 block/genhd.c:680 add_disk include/linux/genhd.h:396 [inline] loop_add+0x615/0x830 drivers/block/loop.c:1904 loop_control_ioctl+0x108/0x2d0 drivers/block/loop.c:2001 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xfe0 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+0xaf/0x190 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3496 [inline] kfree+0xcb/0x260 mm/slab.c:3815 skb_free_head+0x83/0xa0 net/core/skbuff.c:554 skb_release_data+0x57e/0x7d0 net/core/skbuff.c:574 skb_release_all+0x46/0x60 net/core/skbuff.c:631 __kfree_skb net/core/skbuff.c:645 [inline] consume_skb+0xa7/0x330 net/core/skbuff.c:705 skb_free_datagram+0x16/0xe0 net/core/datagram.c:331 unix_dgram_recvmsg+0x70a/0xcd0 net/unix/af_unix.c:2207 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+0x21f/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 ffff8880a8099cc0 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 406 bytes inside of 512-byte region [ffff8880a8099cc0, ffff8880a8099ec0) The buggy address belongs to the page: page:ffffea0002a02640 count:1 mapcount:0 mapping:ffff8880a8099040 index:0x0 flags: 0xfffe0000000100(slab) raw: 00fffe0000000100 ffff8880a8099040 0000000000000000 0000000100000006 raw: ffffea000280cca0 ffffea00023ccde0 ffff8880aa800940 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a8099d00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8880a8099d80: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc >ffff8880a8099e00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff8880a8099e80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880a8099f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================