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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 ffff88804ebb87a0 by task kworker/0:2/2731

CPU: 0 PID: 2731 Comm: kworker/0:2 Not tainted 5.9.0-rc1-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+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
 soft_cursor+0x96b/0xa30 drivers/video/fbdev/core/softcursor.c:61
 bit_cursor+0x1166/0x17d0 drivers/video/fbdev/core/bitblit.c:386
 fb_flashcursor+0x374/0x3e0 drivers/video/fbdev/core/fbcon.c:417
 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 25049:
 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
 netlink_release+0xd43/0x1cf0 net/netlink/af_netlink.c:802
 __sock_release+0xcd/0x280 net/socket.c:596
 sock_close+0x18/0x20 net/socket.c:1277
 __fput+0x285/0x920 fs/file_table.c:281
 task_work_run+0xdd/0x190 kernel/task_work.c:141
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:139 [inline]
 exit_to_user_mode_prepare+0x195/0x1c0 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 ffff88804ebb8000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1952 bytes inside of
 2048-byte region [ffff88804ebb8000, ffff88804ebb8800)
The buggy address belongs to the page:
page:000000001e062418 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x4ebb8
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00012fb948 ffffea0002a2f308 ffff8880aa040800
raw: 0000000000000000 ffff88804ebb8000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88804ebb8680: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88804ebb8700: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88804ebb8780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                               ^
 ffff88804ebb8800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88804ebb8880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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