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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 ffff8880a9e0bccf by task syz-executor.1/9743

CPU: 0 PID: 9743 Comm: syz-executor.1 Not tainted 4.14.226-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+0x1b2/0x281 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252
 kasan_report_error.cold+0x8a/0x191 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:1247
 do_update_region+0x34b/0x5b0 drivers/tty/vt/vt.c:373
 update_region+0xd7/0x110 drivers/tty/vt/vt.c:391
 vcs_write+0x3b9/0xb40 drivers/tty/vt/vc_screen.c:549
 do_loop_readv_writev fs/read_write.c:698 [inline]
 do_loop_readv_writev fs/read_write.c:682 [inline]
 do_iter_write+0x3da/0x550 fs/read_write.c:956
 vfs_writev+0x125/0x290 fs/read_write.c:999
 do_pwritev fs/read_write.c:1088 [inline]
 SYSC_pwritev fs/read_write.c:1135 [inline]
 SyS_pwritev+0x15a/0x200 fs/read_write.c:1130
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x466459
RSP: 002b:00007f2867054188 EFLAGS: 00000246 ORIG_RAX: 0000000000000128
RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000466459
RDX: 0000000000000007 RSI: 0000000020000980 RDI: 0000000000000004
RBP: 00000000004bf9fb R08: 0000000000000008 R09: 0000000000000000
R10: 0000000000000fff R11: 0000000000000246 R12: 000000000056bf60
R13: 00007ffc3488bfdf R14: 00007f2867054300 R15: 0000000000022000

Allocated by task 27815:
 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:2456
 con_font_set drivers/tty/vt/vt.c:4190 [inline]
 con_font_op+0x9e8/0xdb0 drivers/tty/vt/vt.c:4234
 vt_ioctl+0xd5d/0x1d50 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 26324:
 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
 kvfree+0x45/0x50 mm/util.c:416
 __free_fdtable fs/file.c:36 [inline]
 put_files_struct fs/file.c:425 [inline]
 put_files_struct+0x259/0x340 fs/file.c:418
 exit_files+0x7e/0xa0 fs/file.c:450
 do_exit+0xa18/0x2850 kernel/exit.c:863
 do_group_exit+0x100/0x2e0 kernel/exit.c:965
 get_signal+0x38d/0x1ca0 kernel/signal.c:2423
 do_signal+0x7c/0x1550 arch/x86/kernel/signal.c:814
 exit_to_usermode_loop+0x160/0x200 arch/x86/entry/common.c:160
 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 ffff8880a9e0b100
 which belongs to the cache kmalloc-2048 of size 2048
The buggy address is located 975 bytes to the right of
 2048-byte region [ffff8880a9e0b100, ffff8880a9e0b900)
The buggy address belongs to the page:
page:ffffea0002a78280 count:1 mapcount:0 mapping:ffff8880a9e0a000 index:0xffff8880a9e0a000 compound_mapcount: 0
flags: 0xfff00000008100(slab|head)
raw: 00fff00000008100 ffff8880a9e0a000 ffff8880a9e0a000 0000000100000001
raw: ffffea0002d44520 ffffea00023d74a0 ffff88813fe80c40 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a9e0bb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880a9e0bc00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880a9e0bc80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                              ^
 ffff8880a9e0bd00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880a9e0bd80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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