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From: Arvind Sankar <nivedita@alum.mit.edu>
To: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
Christopher Head <bugs@chead.ca>
Subject: [PATCH] x86/sysfb: Fix check for bad VRAM size
Date: Tue, 7 Jan 2020 18:04:10 -0500 [thread overview]
Message-ID: <20200107230410.2291947-1-nivedita@alum.mit.edu> (raw)
When checking whether the reported lfb_size makes sense, we PAGE_ALIGN
height * stride 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 kernel bugzilla linked, an 800x600x32 EFI
framebuffer gets skipped because of this.
Move the PAGE_ALIGN to after the check vs size.
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=206051
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
---
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 01f0e2263b86..298fc1edd9c9 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));
--
2.24.1
next reply other threads:[~2020-01-07 23:04 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-07 23:04 Arvind Sankar [this message]
2020-01-15 13:12 ` Borislav Petkov
2020-01-20 10:14 ` [tip: x86/boot] " tip-bot2 for Arvind Sankar
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