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BUG: KMSAN: uninit-value in writeb arch/x86/include/asm/io.h:65 [inline]
BUG: KMSAN: uninit-value in vga_imageblit_expand drivers/video/fbdev/vga16fb.c:1176 [inline]
BUG: KMSAN: uninit-value in vga16fb_imageblit+0x125e/0x20c0 drivers/video/fbdev/vga16fb.c:1260
CPU: 0 PID: 31844 Comm: kworker/0:2 Not tainted 5.8.0-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+0x21c/0x280 lib/dump_stack.c:118
 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:121
 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:215
 writeb arch/x86/include/asm/io.h:65 [inline]
 vga_imageblit_expand drivers/video/fbdev/vga16fb.c:1176 [inline]
 vga16fb_imageblit+0x125e/0x20c0 drivers/video/fbdev/vga16fb.c:1260
 soft_cursor+0x12bc/0x13f0 drivers/video/fbdev/core/softcursor.c:74
 bit_cursor+0x38c6/0x3a40 drivers/video/fbdev/core/bitblit.c:386
 fb_flashcursor+0x1356/0x1380 drivers/video/fbdev/core/fbcon.c:417
 process_one_work+0x1688/0x2140 kernel/workqueue.c:2269
 worker_thread+0x10bc/0x2730 kernel/workqueue.c:2415
 kthread+0x551/0x590 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:144 [inline]
 kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:310
 __msan_chain_origin+0x50/0x90 mm/kmsan/kmsan_instr.c:165
 __fb_pad_aligned_buffer include/linux/fb.h:655 [inline]
 fb_pad_aligned_buffer+0x7c4/0x8e0 drivers/video/fbdev/core/fbmem.c:116
 soft_cursor+0x1224/0x13f0 drivers/video/fbdev/core/softcursor.c:72
 bit_cursor+0x38c6/0x3a40 drivers/video/fbdev/core/bitblit.c:386
 fb_flashcursor+0x1356/0x1380 drivers/video/fbdev/core/fbcon.c:417
 process_one_work+0x1688/0x2140 kernel/workqueue.c:2269
 worker_thread+0x10bc/0x2730 kernel/workqueue.c:2415
 kthread+0x551/0x590 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:144 [inline]
 kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:310
 kmsan_memcpy_memmove_metadata+0x272/0x2e0 mm/kmsan/kmsan.c:247
 kmsan_memcpy_metadata+0xb/0x10 mm/kmsan/kmsan.c:267
 __msan_memcpy+0x43/0x50 mm/kmsan/kmsan_instr.c:116
 soft_cursor+0x7d7/0x13f0 drivers/video/fbdev/core/softcursor.c:70
 bit_cursor+0x38c6/0x3a40 drivers/video/fbdev/core/bitblit.c:386
 fb_flashcursor+0x1356/0x1380 drivers/video/fbdev/core/fbcon.c:417
 process_one_work+0x1688/0x2140 kernel/workqueue.c:2269
 worker_thread+0x10bc/0x2730 kernel/workqueue.c:2415
 kthread+0x551/0x590 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:144 [inline]
 kmsan_internal_poison_shadow+0x66/0xd0 mm/kmsan/kmsan.c:127
 kmsan_slab_alloc+0x8a/0xe0 mm/kmsan/kmsan_hooks.c:80
 slab_alloc_node mm/slub.c:2839 [inline]
 slab_alloc mm/slub.c:2848 [inline]
 __kmalloc+0x312/0x410 mm/slub.c:3911
 kmalloc include/linux/slab.h:560 [inline]
 fbcon_set_font+0x5ad/0xfb0 drivers/video/fbdev/core/fbcon.c:2673
 con_font_set drivers/tty/vt/vt.c:4571 [inline]
 con_font_op+0x1e59/0x2290 drivers/tty/vt/vt.c:4636
 vt_ioctl+0x99e/0x6a40 drivers/tty/vt/vt_ioctl.c:917
 vt_compat_ioctl+0x59b/0x1040 drivers/tty/vt/vt_ioctl.c:1242
 tty_compat_ioctl+0x74b/0x1660 drivers/tty/tty_io.c:2847
 __do_compat_sys_ioctl fs/ioctl.c:847 [inline]
 __se_compat_sys_ioctl+0x55f/0x1100 fs/ioctl.c:798
 __ia32_compat_sys_ioctl+0x4a/0x70 fs/ioctl.c:798
 do_syscall_32_irqs_on arch/x86/entry/common.c:430 [inline]
 __do_fast_syscall_32+0x2af/0x480 arch/x86/entry/common.c:477
 do_fast_syscall_32+0x6b/0xd0 arch/x86/entry/common.c:505
 do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:554
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
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