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BUG: KASAN: global-out-of-bounds in __fb_pad_aligned_buffer include/linux/fb.h:654 [inline]
BUG: KASAN: global-out-of-bounds in bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline]
BUG: KASAN: global-out-of-bounds in bit_putcs+0xd5d/0xf10 drivers/video/fbdev/core/bitblit.c:185
Read of size 1 at addr ffffffff8872bb44 by task syz-executor850/18543

CPU: 0 PID: 18543 Comm: syz-executor850 Not tainted 5.5.0-rc2-next-20191218-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+0x197/0x210 lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0x5/0x30b mm/kasan/report.c:374
 __kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506
 kasan_report+0x12/0x20 mm/kasan/common.c:639
 __asan_report_load1_noabort+0x14/0x20 mm/kasan/generic_report.c:132
 __fb_pad_aligned_buffer include/linux/fb.h:654 [inline]
 bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline]
 bit_putcs+0xd5d/0xf10 drivers/video/fbdev/core/bitblit.c:185
 fbcon_putcs+0x33c/0x3e0 drivers/video/fbdev/core/fbcon.c:1353
 con_flush drivers/tty/vt/vt.c:2546 [inline]
 do_con_write.part.0+0xebd/0x1ef0 drivers/tty/vt/vt.c:2799
 do_con_write drivers/tty/vt/vt.c:2565 [inline]
 con_write+0x46/0xd0 drivers/tty/vt/vt.c:3135
 process_output_block drivers/tty/n_tty.c:595 [inline]
 n_tty_write+0x40e/0x1080 drivers/tty/n_tty.c:2333
 do_tty_write drivers/tty/tty_io.c:962 [inline]
 tty_write+0x496/0x7f0 drivers/tty/tty_io.c:1046
 __vfs_write+0x8a/0x110 fs/read_write.c:494
 vfs_write+0x268/0x5d0 fs/read_write.c:558
 ksys_write+0x14f/0x290 fs/read_write.c:611
 __do_sys_write fs/read_write.c:623 [inline]
 __se_sys_write fs/read_write.c:620 [inline]
 __x64_sys_write+0x73/0xb0 fs/read_write.c:620
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x447d39
Code: e8 1c e6 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 8b 06 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fe6827abce8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00000000006ddc68 RCX: 0000000000447d39
RDX: 00000000fffffe4d RSI: 0000000020000340 RDI: 0000000000000003
RBP: 00000000006ddc60 R08: 00007fe6827ac700 R09: 0000000000000000
R10: 00007fe6827ac700 R11: 0000000000000246 R12: 00000000006ddc6c
R13: 00007ffd499e6fdf R14: 00007fe6827ac9c0 R15: 0000000000000001

The buggy address belongs to the variable:
 __func__.44397+0x104/0x1c0

Memory state around the buggy address:
 ffffffff8872ba00: 00 00 00 00 fa fa fa fa 00 03 fa fa fa fa fa fa
 ffffffff8872ba80: 00 01 fa fa fa fa fa fa 04 fa fa fa fa fa fa fa
>ffffffff8872bb00: 04 fa fa fa fa fa fa fa 04 fa fa fa fa fa fa fa
                                           ^
 ffffffff8872bb80: 04 fa fa fa fa fa fa fa 07 fa fa fa fa fa fa fa
 ffffffff8872bc00: 04 fa fa fa fa fa fa fa 00 00 01 fa fa fa fa fa
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