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BUG: KASAN: slab-out-of-bounds in __fb_pad_aligned_buffer include/linux/fb.h:655 [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+0xbb6/0xd20 drivers/video/fbdev/core/bitblit.c:185
Read of size 1 at addr ffff8880a1d92230 by task syz-executor726/6823

CPU: 0 PID: 6823 Comm: syz-executor726 Not tainted 5.8.0-rc4-next-20200710-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x18f/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 __fb_pad_aligned_buffer include/linux/fb.h:655 [inline]
 bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline]
 bit_putcs+0xbb6/0xd20 drivers/video/fbdev/core/bitblit.c:185
 fbcon_putcs+0x33c/0x3f0 drivers/video/fbdev/core/fbcon.c:1362
 do_update_region+0x399/0x630 drivers/tty/vt/vt.c:675
 redraw_screen+0x64e/0x770 drivers/tty/vt/vt.c:1034
 vc_do_resize+0xeec/0x1170 drivers/tty/vt/vt.c:1319
 vt_resizex drivers/tty/vt/vt_ioctl.c:814 [inline]
 vt_ioctl+0xeba/0x2c20 drivers/tty/vt/vt_ioctl.c:1026
 tty_ioctl+0x1019/0x15f0 drivers/tty/tty_io.c:2656
 vfs_ioctl fs/ioctl.c:48 [inline]
 ksys_ioctl+0x11a/0x180 fs/ioctl.c:753
 __do_sys_ioctl fs/ioctl.c:762 [inline]
 __se_sys_ioctl fs/ioctl.c:760 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:760
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x4403a9
Code: Bad RIP value.
RSP: 002b:00007fffdfee7ce8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004403a9
RDX: 0000000020000080 RSI: 000000000000560a RDI: 0000000000000004
RBP: 00000000006ca018 R08: 000000000000000d R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401c10
R13: 0000000000401ca0 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 6823:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
 kasan_set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461
 __do_kmalloc mm/slab.c:3655 [inline]
 __kmalloc+0x1a8/0x320 mm/slab.c:3664
 kmalloc include/linux/slab.h:559 [inline]
 fbcon_set_font+0x34f/0x8b0 drivers/video/fbdev/core/fbcon.c:2673
 con_font_set drivers/tty/vt/vt.c:4655 [inline]
 con_font_op+0xd25/0x1110 drivers/tty/vt/vt.c:4720
 vt_io_ioctl drivers/tty/vt/vt_ioctl.c:595 [inline]
 vt_ioctl+0x1be1/0x2c20 drivers/tty/vt/vt_ioctl.c:846
 tty_ioctl+0x1019/0x15f0 drivers/tty/tty_io.c:2656
 vfs_ioctl fs/ioctl.c:48 [inline]
 ksys_ioctl+0x11a/0x180 fs/ioctl.c:753
 __do_sys_ioctl fs/ioctl.c:762 [inline]
 __se_sys_ioctl fs/ioctl.c:760 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:760
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff8880a1d92000
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 560 bytes inside of
 1024-byte region [ffff8880a1d92000, ffff8880a1d92400)
The buggy address belongs to the page:
page:00000000d6cd4725 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0xa1d92
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea000256b548 ffffea00023751c8 ffff8880aa000700
raw: 0000000000000000 ffff8880a1d92000 0000000100000002 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a1d92100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880a1d92180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880a1d92200: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                     ^
 ffff8880a1d92280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880a1d92300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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