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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: 5288 Comm: syz-executor.0 Not tainted 5.9.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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+0x58/0xa0 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+0x125e/0x20c0 drivers/video/fbdev/vga16fb.c:1260
 bit_putcs+0x3039/0x3390 drivers/video/fbdev/core/bitblit.c:105
 fbcon_putcs+0x121c/0x1250 drivers/video/fbdev/core/fbcon.c:1362
 do_update_region+0x5d7/0xc10 drivers/tty/vt/vt.c:665
 redraw_screen+0x146d/0x16c0 drivers/tty/vt/vt.c:1034
 fbcon_modechanged+0x110d/0x1320 drivers/video/fbdev/core/fbcon.c:3022
 fbcon_update_vcs+0x86/0xa0 drivers/video/fbdev/core/fbcon.c:3069
 do_fb_ioctl+0xf54/0x10b0 drivers/video/fbdev/core/fbmem.c:1106
 fb_compat_ioctl+0x57e/0x1f60 drivers/video/fbdev/core/fbmem.c:1311
 __do_compat_sys_ioctl fs/ioctl.c:842 [inline]
 __se_compat_sys_ioctl+0x55f/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
RIP: 0023:0xf7fef549
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 002b:00000000f55e90cc EFLAGS: 00000296 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000004601
RDX: 0000000020000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:143 [inline]
 kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:311
 __msan_chain_origin+0x50/0x90 mm/kmsan/kmsan_instr.c:151
 __fb_pad_aligned_buffer include/linux/fb.h:654 [inline]
 bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline]
 bit_putcs+0x2df0/0x3390 drivers/video/fbdev/core/bitblit.c:185
 fbcon_putcs+0x121c/0x1250 drivers/video/fbdev/core/fbcon.c:1362
 do_update_region+0x5d7/0xc10 drivers/tty/vt/vt.c:665
 redraw_screen+0x146d/0x16c0 drivers/tty/vt/vt.c:1034
 fbcon_modechanged+0x110d/0x1320 drivers/video/fbdev/core/fbcon.c:3022
 fbcon_update_vcs+0x86/0xa0 drivers/video/fbdev/core/fbcon.c:3069
 do_fb_ioctl+0xf54/0x10b0 drivers/video/fbdev/core/fbmem.c:1106
 fb_compat_ioctl+0x57e/0x1f60 drivers/video/fbdev/core/fbmem.c:1311
 __do_compat_sys_ioctl fs/ioctl.c:842 [inline]
 __se_compat_sys_ioctl+0x55f/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

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:143 [inline]
 kmsan_internal_poison_shadow+0x66/0xd0 mm/kmsan/kmsan.c:126
 kmsan_slab_alloc+0x8a/0xe0 mm/kmsan/kmsan_hooks.c:80
 slab_alloc_node mm/slub.c:2907 [inline]
 __kmalloc_node_track_caller+0x9aa/0x12f0 mm/slub.c:4511
 __kmalloc_reserve net/core/skbuff.c:142 [inline]
 __alloc_skb+0x35f/0xb30 net/core/skbuff.c:210
 alloc_skb include/linux/skbuff.h:1094 [inline]
 alloc_uevent_skb+0x149/0x430 lib/kobject_uevent.c:289
 uevent_net_broadcast_untagged lib/kobject_uevent.c:325 [inline]
 kobject_uevent_net_broadcast lib/kobject_uevent.c:408 [inline]
 kobject_uevent_env+0x1e35/0x2cc0 lib/kobject_uevent.c:592
 kvm_uevent_notify_change+0xac4/0xb40 arch/x86/kvm/../../../virt/kvm/kvm_main.c:4649
 kvm_dev_ioctl_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:3944 [inline]
 kvm_dev_ioctl+0x2489/0x2fc0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3966
 __do_compat_sys_ioctl fs/ioctl.c:842 [inline]
 __se_compat_sys_ioctl+0x55f/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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