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BUG: KASAN: vmalloc-out-of-bounds in fast_imageblit drivers/video/fbdev/core/sysimgblt.c:229 [inline]
BUG: KASAN: vmalloc-out-of-bounds in sys_imageblit+0x117f/0x1290 drivers/video/fbdev/core/sysimgblt.c:275
Write of size 4 at addr ffffc90009b09000 by task kworker/0:0/29884

CPU: 0 PID: 29884 Comm: kworker/0:0 Not tainted 5.9.0-rc8-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
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+0x5/0x497 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 fast_imageblit drivers/video/fbdev/core/sysimgblt.c:229 [inline]
 sys_imageblit+0x117f/0x1290 drivers/video/fbdev/core/sysimgblt.c:275
 drm_fb_helper_sys_imageblit+0x1c/0x180 drivers/gpu/drm/drm_fb_helper.c:767
 soft_cursor+0x514/0xa30 drivers/video/fbdev/core/softcursor.c:74
 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


Memory state around the buggy address:
 ffffc90009b08f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90009b08f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc90009b09000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
                   ^
 ffffc90009b09080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc90009b09100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
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