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From: Kairui Song <kasong@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Ard Biesheuvel <ardb@kernel.org>,
	"K. Y. Srinivasan" <kys@microsoft.com>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	Wei Liu <wei.liu@kernel.org>, Dexuan Cui <decui@microsoft.com>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
	Dave Young <dyoung@redhat.com>,
	x86@kernel.org, linux-hyperv@vger.kernel.org,
	kexec@lists.infradead.org, Kairui Song <kasong@redhat.com>
Subject: [PATCH 1/2] x86/kexec: Use up-to-dated screen_info copy to fill boot params
Date: Wed, 14 Oct 2020 17:24:28 +0800	[thread overview]
Message-ID: <20201014092429.1415040-2-kasong@redhat.com> (raw)
In-Reply-To: <20201014092429.1415040-1-kasong@redhat.com>

kexec_file_load now just reuse the old boot_params.screen_info.
But if drivers have change the hardware state, boot_param.screen_info
could contain invalid info.

For example, the video type might be no longer VGA, or frame buffer
address changed. If kexec kernel keep using the old screen_info,
kexec'ed kernel may attempt to write to an invalid framebuffer
memory region.

There are two screen_info globally available, boot_params.screen_info
and screen_info. Later one is a copy, and could be updated by drivers.

So let kexec_file_load use the updated copy.

Signed-off-by: Kairui Song <kasong@redhat.com>
---
 arch/x86/kernel/kexec-bzimage64.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
index 57c2ecf43134..ce831f9448e7 100644
--- a/arch/x86/kernel/kexec-bzimage64.c
+++ b/arch/x86/kernel/kexec-bzimage64.c
@@ -200,8 +200,7 @@ setup_boot_parameters(struct kimage *image, struct boot_params *params,
 	params->hdr.hardware_subarch = boot_params.hdr.hardware_subarch;
 
 	/* Copying screen_info will do? */
-	memcpy(&params->screen_info, &boot_params.screen_info,
-				sizeof(struct screen_info));
+	memcpy(&params->screen_info, &screen_info, sizeof(struct screen_info));
 
 	/* Fill in memsize later */
 	params->screen_info.ext_mem_k = 0;
-- 
2.28.0


WARNING: multiple messages have this Message-ID (diff)
From: Kairui Song <kasong@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: Wei Liu <wei.liu@kernel.org>, Kairui Song <kasong@redhat.com>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
	kexec@lists.infradead.org, Haiyang Zhang <haiyangz@microsoft.com>,
	x86@kernel.org, Dexuan Cui <decui@microsoft.com>,
	linux-hyperv@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
	Borislav Petkov <bp@alien8.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	"K. Y. Srinivasan" <kys@microsoft.com>,
	Dave Young <dyoung@redhat.com>, Ard Biesheuvel <ardb@kernel.org>
Subject: [PATCH 1/2] x86/kexec: Use up-to-dated screen_info copy to fill boot params
Date: Wed, 14 Oct 2020 17:24:28 +0800	[thread overview]
Message-ID: <20201014092429.1415040-2-kasong@redhat.com> (raw)
In-Reply-To: <20201014092429.1415040-1-kasong@redhat.com>

kexec_file_load now just reuse the old boot_params.screen_info.
But if drivers have change the hardware state, boot_param.screen_info
could contain invalid info.

For example, the video type might be no longer VGA, or frame buffer
address changed. If kexec kernel keep using the old screen_info,
kexec'ed kernel may attempt to write to an invalid framebuffer
memory region.

There are two screen_info globally available, boot_params.screen_info
and screen_info. Later one is a copy, and could be updated by drivers.

So let kexec_file_load use the updated copy.

Signed-off-by: Kairui Song <kasong@redhat.com>
---
 arch/x86/kernel/kexec-bzimage64.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
index 57c2ecf43134..ce831f9448e7 100644
--- a/arch/x86/kernel/kexec-bzimage64.c
+++ b/arch/x86/kernel/kexec-bzimage64.c
@@ -200,8 +200,7 @@ setup_boot_parameters(struct kimage *image, struct boot_params *params,
 	params->hdr.hardware_subarch = boot_params.hdr.hardware_subarch;
 
 	/* Copying screen_info will do? */
-	memcpy(&params->screen_info, &boot_params.screen_info,
-				sizeof(struct screen_info));
+	memcpy(&params->screen_info, &screen_info, sizeof(struct screen_info));
 
 	/* Fill in memsize later */
 	params->screen_info.ext_mem_k = 0;
-- 
2.28.0


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

  reply	other threads:[~2020-10-14  9:26 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-14  9:24 [PATCH 0/2] x86/hyperv: fix kexec/kdump hang on some VMs Kairui Song
2020-10-14  9:24 ` Kairui Song
2020-10-14  9:24 ` Kairui Song [this message]
2020-10-14  9:24   ` [PATCH 1/2] x86/kexec: Use up-to-dated screen_info copy to fill boot params Kairui Song
2020-10-14 15:43   ` [tip: x86/urgent] " tip-bot2 for Kairui Song
2020-10-27 20:07     ` Thomas Gleixner
2020-11-17  3:39   ` [PATCH 1/2] " Dexuan Cui
2020-11-17  3:39     ` Dexuan Cui
2020-11-25 23:39     ` Dexuan Cui
2020-11-25 23:39       ` Dexuan Cui
2020-10-14  9:24 ` [PATCH 2/2] hyperv_fb: Update screen_info after removing old framebuffer Kairui Song
2020-10-14  9:24   ` Kairui Song
2020-10-14 15:43   ` [tip: x86/urgent] " tip-bot2 for Kairui Song

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