audit: type=1400 audit(1602047127.319:8): avc:  denied  { execmem } for  pid=6353 comm="syz-executor652" scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=process permissive=1
==================================================================
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 ffff8880a7da5b3e by task syz-executor652/6353

CPU: 1 PID: 6353 Comm: syz-executor652 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
 con_flush drivers/tty/vt/vt.c:2206 [inline]
 do_con_write+0x9dd/0x19b0 drivers/tty/vt/vt.c:2453
 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: 0033:0x4403c9
RSP: 002b:00007ffdbc816238 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004403c9
RDX: 0000000000001006 RSI: 0000000020000180 RDI: 0000000000000006
RBP: 00000000006cb018 R08: 00000000004002c8 R09: 00000000004002c8
R10: 000000000000000d R11: 0000000000000246 R12: 0000000000401c30
R13: 0000000000401cc0 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 6335:
 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_array include/linux/slab.h:607 [inline]
 kcalloc include/linux/slab.h:618 [inline]
 alloc_pipe_info+0x140/0x3c0 fs/pipe.c:664
 get_pipe_inode fs/pipe.c:726 [inline]
 create_pipe_files+0xc4/0x880 fs/pipe.c:759
 __do_pipe_flags fs/pipe.c:816 [inline]
 SYSC_pipe2 fs/pipe.c:864 [inline]
 SyS_pipe2+0x76/0x160 fs/pipe.c:858
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 6335:
 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
 free_pipe_info+0x1f0/0x2a0 fs/pipe.c:697
 put_pipe_info fs/pipe.c:575 [inline]
 pipe_release+0x29f/0x300 fs/pipe.c:596
 __fput+0x25f/0x7a0 fs/file_table.c:210
 task_work_run+0x11f/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1ad/0x200 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

The buggy address belongs to the object at ffff8880a7da56c0
 which belongs to the cache kmalloc-1024 of size 1024
The buggy address is located 126 bytes to the right of
 1024-byte region [ffff8880a7da56c0, ffff8880a7da5ac0)
The buggy address belongs to the page:
page:ffffea00029f6900 count:1 mapcount:0 mapping:ffff8880a7da4040 index:0x0 compound_mapcount: 0
flags: 0xfffe0000008100(slab|head)
raw: 00fffe0000008100 ffff8880a7da4040 0000000000000000 0000000100000007
raw: ffffea00029f1620 ffffea00029f69a0 ffff88812fe50ac0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a7da5a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a7da5a80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff8880a7da5b00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
                                        ^
 ffff8880a7da5b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a7da5c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================