From: Borislav Petkov <bp@alien8.de>
To: Christopher Head <bugs@chead.ca>
Cc: Arvind Sankar <nivedita@alum.mit.edu>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86/sysfb: Fix check for bad VRAM size
Date: Wed, 15 Jan 2020 14:12:06 +0100 [thread overview]
Message-ID: <20200115131206.GF20975@zn.tnic> (raw)
In-Reply-To: <20200107230410.2291947-1-nivedita@alum.mit.edu>
On Tue, Jan 07, 2020 at 06:04:10PM -0500, Arvind Sankar wrote:
> 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));
> --
Christopher,
can I add your Reported-by: and Tested-by: tags to the patch?
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2020-01-15 13:12 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 [this message]
2020-01-20 10:14 ` [tip: x86/boot] " tip-bot2 for Arvind Sankar
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