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BUG: KASAN: slab-out-of-bounds in __fb_pad_aligned_buffer include/linux/fb.h:654 [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 ffff88809e44d14b by task syz-executor.4/14481

CPU: 1 PID: 14481 Comm: syz-executor.4 Not tainted 5.8.0-next-20200810-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:654 [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
 con_flush drivers/tty/vt/vt.c:2574 [inline]
 vc_con_write_normal drivers/tty/vt/vt.c:2842 [inline]
 do_con_write+0x10e9/0x1d70 drivers/tty/vt/vt.c:2909
 con_write+0x22/0xb0 drivers/tty/vt/vt.c:3249
 process_output_block drivers/tty/n_tty.c:595 [inline]
 n_tty_write+0x3ce/0xf80 drivers/tty/n_tty.c:2333
 do_tty_write drivers/tty/tty_io.c:962 [inline]
 tty_write+0x4d9/0x870 drivers/tty/tty_io.c:1046
 do_loop_readv_writev fs/read_write.c:754 [inline]
 do_loop_readv_writev fs/read_write.c:738 [inline]
 do_iter_write+0x489/0x670 fs/read_write.c:1037
 vfs_writev+0x1aa/0x2e0 fs/read_write.c:1108
 do_writev+0x139/0x300 fs/read_write.c:1151
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45ce69
Code: 2d b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 fb b5 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f726e597c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 0000000000038d40 RCX: 000000000045ce69
RDX: 0000000000000003 RSI: 0000000020000200 RDI: 0000000000000004
RBP: 000000000118bf60 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118bf2c
R13: 00007ffc38459f5f R14: 00007f726e5989c0 R15: 000000000118bf2c

Allocated by task 9142:
 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:4662 [inline]
 con_font_op+0xd25/0x1110 drivers/tty/vt/vt.c:4727
 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]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl fs/ioctl.c:739 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Last call_rcu():
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
 kasan_record_aux_stack+0x82/0xb0 mm/kasan/generic.c:346
 __call_rcu kernel/rcu/tree.c:2894 [inline]
 call_rcu+0x14f/0x7e0 kernel/rcu/tree.c:2968
 put_ctx kernel/events/core.c:1271 [inline]
 put_ctx+0x116/0x1e0 kernel/events/core.c:1264
 perf_event_exit_task_context kernel/events/core.c:12335 [inline]
 perf_event_exit_task+0xb54/0xef0 kernel/events/core.c:12364
 do_exit+0xb8d/0x29f0 kernel/exit.c:815
 do_group_exit+0x125/0x310 kernel/exit.c:903
 get_signal+0x40b/0x1ee0 kernel/signal.c:2743
 arch_do_signal+0x82/0x2520 arch/x86/kernel/signal.c:811
 exit_to_user_mode_loop kernel/entry/common.c:135 [inline]
 exit_to_user_mode_prepare+0x15d/0x1c0 kernel/entry/common.c:166
 syscall_exit_to_user_mode+0x59/0x2b0 kernel/entry/common.c:241
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff88809e44d000
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 331 bytes inside of
 512-byte region [ffff88809e44d000, ffff88809e44d200)
The buggy address belongs to the page:
page:0000000040eb5e26 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x9e44d
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00027bfe08 ffffea00029990c8 ffff8880aa040600
raw: 0000000000000000 ffff88809e44d000 0000000100000004 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809e44d000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88809e44d080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88809e44d100: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                              ^
 ffff88809e44d180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88809e44d200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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