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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+0xe4b/0x1b20 drivers/video/fbdev/vga16fb.c:1260
CPU: 1 PID: 28914 Comm: kworker/1:0 Not tainted 5.9.0-rc8-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:122
 __msan_warning+0x5f/0xa0 mm/kmsan/kmsan_instr.c:201
 writeb arch/x86/include/asm/io.h:65 [inline]
 vga_imageblit_expand drivers/video/fbdev/vga16fb.c:1176 [inline]
 vga16fb_imageblit+0xe4b/0x1b20 drivers/video/fbdev/vga16fb.c:1260
 soft_cursor+0x1276/0x13b0 drivers/video/fbdev/core/softcursor.c:74
 bit_cursor+0x37e2/0x3970 drivers/video/fbdev/core/bitblit.c:377
 fb_flashcursor+0x12a3/0x12d0 drivers/video/fbdev/core/fbcon.c:397
 process_one_work+0x1224/0x20a0 kernel/workqueue.c:2269
 worker_thread+0x10cc/0x2740 kernel/workqueue.c:2415
 kthread+0x51c/0x560 kernel/kthread.c:293
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:129 [inline]
 kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:297
 __msan_chain_origin+0x57/0xa0 mm/kmsan/kmsan_instr.c:151
 __fb_pad_aligned_buffer include/linux/fb.h:654 [inline]
 fb_pad_aligned_buffer+0x771/0x8b0 drivers/video/fbdev/core/fbmem.c:116
 soft_cursor+0x11d9/0x13b0 drivers/video/fbdev/core/softcursor.c:72
 bit_cursor+0x37e2/0x3970 drivers/video/fbdev/core/bitblit.c:377
 fb_flashcursor+0x12a3/0x12d0 drivers/video/fbdev/core/fbcon.c:397
 process_one_work+0x1224/0x20a0 kernel/workqueue.c:2269
 worker_thread+0x10cc/0x2740 kernel/workqueue.c:2415
 kthread+0x51c/0x560 kernel/kthread.c:293
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:129 [inline]
 kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:297
 kmsan_memcpy_memmove_metadata+0x25e/0x2d0 mm/kmsan/kmsan.c:234
 kmsan_memcpy_metadata+0xb/0x10 mm/kmsan/kmsan.c:254
 __msan_memcpy+0x46/0x60 mm/kmsan/kmsan_instr.c:114
 soft_cursor+0x79b/0x13b0 drivers/video/fbdev/core/softcursor.c:70
 bit_cursor+0x37e2/0x3970 drivers/video/fbdev/core/bitblit.c:377
 fb_flashcursor+0x12a3/0x12d0 drivers/video/fbdev/core/fbcon.c:397
 process_one_work+0x1224/0x20a0 kernel/workqueue.c:2269
 worker_thread+0x10cc/0x2740 kernel/workqueue.c:2415
 kthread+0x51c/0x560 kernel/kthread.c:293
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:129 [inline]
 kmsan_internal_poison_shadow+0x5c/0xf0 mm/kmsan/kmsan.c:112
 kmsan_slab_alloc+0x8d/0xe0 mm/kmsan/kmsan_hooks.c:80
 slab_alloc_node mm/slub.c:2903 [inline]
 slab_alloc mm/slub.c:2912 [inline]
 __kmalloc+0x282/0x490 mm/slub.c:3978
 kmalloc include/linux/slab.h:559 [inline]
 fbcon_set_font+0x5ac/0xf40 drivers/video/fbdev/core/fbcon.c:2496
 con_font_set drivers/tty/vt/vt.c:4663 [inline]
 con_font_op+0x204e/0x21b0 drivers/tty/vt/vt.c:4728
 vt_io_ioctl drivers/tty/vt/vt_ioctl.c:586 [inline]
 vt_ioctl+0x14b2/0x67e0 drivers/tty/vt/vt_ioctl.c:856
 vt_compat_ioctl+0x5cb/0x1030 drivers/tty/vt/vt_ioctl.c:1257
 tty_compat_ioctl+0x74b/0x1660 drivers/tty/tty_io.c:2847
 __do_compat_sys_ioctl fs/ioctl.c:842 [inline]
 __se_compat_sys_ioctl+0x53d/0x1100 fs/ioctl.c:793
 __ia32_compat_sys_ioctl+0x4a/0x70 fs/ioctl.c:793
 do_syscall_32_irqs_on arch/x86/entry/common.c:80 [inline]
 __do_fast_syscall_32+0x129/0x180 arch/x86/entry/common.c:139
 do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:162
 do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:205
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
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