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BUG: KASAN: slab-out-of-bounds in soft_cursor+0x96b/0xa30 drivers/video/fbdev/core/softcursor.c:61
Read of size 1 at addr ffff88805c83b210 by task kworker/0:31/8945

CPU: 0 PID: 8945 Comm: kworker/0:31 Not tainted 5.9.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_power_efficient fb_flashcursor
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x198/0x1fd 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
 soft_cursor+0x96b/0xa30 drivers/video/fbdev/core/softcursor.c:61
 bit_cursor+0xcfe/0x1720 drivers/video/fbdev/core/bitblit.c:377
 fb_flashcursor+0x38b/0x430 drivers/video/fbdev/core/fbcon.c:397
 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
 kthread+0x3b5/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

Allocated by task 28907:
 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+0x1b0/0x360 mm/slab.c:3664
 kmalloc include/linux/slab.h:559 [inline]
 fbcon_set_font+0x363/0x9b0 drivers/video/fbdev/core/fbcon.c:2496
 con_font_set drivers/tty/vt/vt.c:4663 [inline]
 con_font_op+0xd26/0x1140 drivers/tty/vt/vt.c:4728
 vt_io_ioctl drivers/tty/vt/vt_ioctl.c:595 [inline]
 vt_ioctl+0x1ce7/0x2e90 drivers/tty/vt/vt_ioctl.c:856
 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

The buggy address belongs to the object at ffff88805c83b000
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 16 bytes to the right of
 512-byte region [ffff88805c83b000, ffff88805c83b200)
The buggy address belongs to the page:
page:00000000fa14e7d1 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88805c83b400 pfn:0x5c83b
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00029be708 ffffea0002a32ec8 ffff8880aa040600
raw: ffff88805c83b400 ffff88805c83b000 0000000100000002 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88805c83b100: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88805c83b180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88805c83b200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                         ^
 ffff88805c83b280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88805c83b300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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