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From: "tip-bot2 for Arvind Sankar" <>
Cc: Christopher Head <>,
	Arvind Sankar <>,
	Borislav Petkov <>, x86 <>,
	LKML <>
Subject: [tip: x86/boot] x86/sysfb: Fix check for bad VRAM size
Date: Mon, 20 Jan 2020 10:14:07 -0000	[thread overview]
Message-ID: <157951524757.396.6875449897563073243.tip-bot2@tip-bot2> (raw)
In-Reply-To: <>

The following commit has been merged into the x86/boot branch of tip:

Commit-ID:     dacc9092336be20b01642afe1a51720b31f60369
Author:        Arvind Sankar <>
AuthorDate:    Tue, 07 Jan 2020 18:04:10 -05:00
Committer:     Borislav Petkov <>
CommitterDate: Mon, 20 Jan 2020 10:57:53 +01:00

x86/sysfb: Fix check for bad VRAM size

When checking whether the reported lfb_size makes sense, the height
* stride result is page-aligned before seeing whether it exceeds the
reported size.

This doesn't work if height * stride is not an exact number of pages.
For example, as reported in the kernel bugzilla below, an 800x600x32 EFI
framebuffer gets skipped because of this.

Move the PAGE_ALIGN to after the check vs size.

Reported-by: Christopher Head <>
Tested-by: Christopher Head <>
Signed-off-by: Arvind Sankar <>
Signed-off-by: Borislav Petkov <>
 arch/x86/kernel/sysfb_simplefb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/sysfb_simplefb.c b/arch/x86/kernel/sysfb_simplefb.c
index 01f0e22..298fc1e 100644
--- a/arch/x86/kernel/sysfb_simplefb.c
+++ b/arch/x86/kernel/sysfb_simplefb.c
@@ -90,11 +90,11 @@ __init int create_simplefb(const struct screen_info *si,
 	if (si->orig_video_isVGA == VIDEO_TYPE_VLFB)
 		size <<= 16;
 	length = mode->height * mode->stride;
-	length = PAGE_ALIGN(length);
 	if (length > size) {
 		printk(KERN_WARNING "sysfb: VRAM smaller than advertised\n");
 		return -EINVAL;
+	length = PAGE_ALIGN(length);
 	/* setup IORESOURCE_MEM as framebuffer memory */
 	memset(&res, 0, sizeof(res));

      parent reply	other threads:[~2020-01-20 10:14 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-07 23:04 [PATCH] x86/sysfb: Fix check for bad VRAM size Arvind Sankar
2020-01-15 13:12 ` Borislav Petkov
2020-01-20 10:14 ` tip-bot2 for Arvind Sankar [this message]

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