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BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:406 [inline]
BUG: KASAN: slab-out-of-bounds in soft_cursor+0x44b/0xa30 drivers/video/fbdev/core/softcursor.c:70
Read of size 12 at addr ffff88809e0a4d90 by task kworker/0:10/13831

CPU: 0 PID: 13831 Comm: kworker/0:10 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
 check_memory_region_inline mm/kasan/generic.c:186 [inline]
 check_memory_region+0x13d/0x180 mm/kasan/generic.c:192
 memcpy+0x20/0x60 mm/kasan/common.c:105
 memcpy include/linux/string.h:406 [inline]
 soft_cursor+0x44b/0xa30 drivers/video/fbdev/core/softcursor.c:70
 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 16217:
 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

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+0x15e/0x7c0 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+0xb5d/0xf10 kernel/events/core.c:12364
 do_exit+0xb8d/0x29f0 kernel/exit.c:815
 do_group_exit+0x125/0x310 kernel/exit.c:903
 get_signal+0x428/0x1f00 kernel/signal.c:2757
 arch_do_signal+0x82/0x2520 arch/x86/kernel/signal.c:811
 exit_to_user_mode_loop kernel/entry/common.c:159 [inline]
 exit_to_user_mode_prepare+0x1ae/0x200 kernel/entry/common.c:190
 syscall_exit_to_user_mode+0x7e/0x2e0 kernel/entry/common.c:265
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Second to 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+0x15e/0x7c0 kernel/rcu/tree.c:2968
 percpu_ref_put_many include/linux/percpu-refcount.h:309 [inline]
 percpu_ref_put include/linux/percpu-refcount.h:325 [inline]
 percpu_ref_call_confirm_rcu lib/percpu-refcount.c:131 [inline]
 percpu_ref_switch_to_atomic_rcu+0x536/0x620 lib/percpu-refcount.c:166
 rcu_do_batch kernel/rcu/tree.c:2428 [inline]
 rcu_core+0x5ca/0x1130 kernel/rcu/tree.c:2656
 __do_softirq+0x1f8/0xb23 kernel/softirq.c:298

The buggy address belongs to the object at ffff88809e0a4c00
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 400 bytes inside of
 512-byte region [ffff88809e0a4c00, ffff88809e0a4e00)
The buggy address belongs to the page:
page:00000000d4509e99 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x9e0a4
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea0001b6d848 ffffea0002880548 ffff8880aa040600
raw: 0000000000000000 ffff88809e0a4000 0000000100000004 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809e0a4c80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88809e0a4d00: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88809e0a4d80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                         ^
 ffff88809e0a4e00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88809e0a4e80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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