linux-kernel - [090/200] x86/amd-iommu: Fix crash when request_mem

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Message-Id: <20100701174254.021670541@clark.site>
Date:	Thu, 01 Jul 2010 10:43:00 -0700
From:	Greg KH <gregkh@...e.de>
To:	linux-kernel@...r.kernel.org, stable@...nel.org
Cc:	stable-review@...nel.org, torvalds@...ux-foundation.org,
	akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
	Joerg Roedel <joerg.roedel@....com>
Subject: [090/200] x86/amd-iommu: Fix crash when request_mem_region fails

2.6.34-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Joerg Roedel <joerg.roedel@....com>

commit e82752d8b5a7e0a5e4d607fd8713549e2a4e2741 upstream.

When request_mem_region fails the error path tries to
disable the IOMMUs. This accesses the mmio-region which was
not allocated leading to a kernel crash. This patch fixes
the issue.

Signed-off-by: Joerg Roedel <joerg.roedel@....com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>

---
 arch/x86/kernel/amd_iommu_init.c |   11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -286,8 +286,12 @@ static u8 * __init iommu_map_mmio_space(
 {
 	u8 *ret;
 
-	if (!request_mem_region(address, MMIO_REGION_LENGTH, "amd_iommu"))
+	if (!request_mem_region(address, MMIO_REGION_LENGTH, "amd_iommu")) {
+		pr_err("AMD-Vi: Can not reserve memory region %llx for mmio\n",
+			address);
+		pr_err("AMD-Vi: This is a BIOS bug. Please contact your hardware vendor\n");
 		return NULL;
+	}
 
 	ret = ioremap_nocache(address, MMIO_REGION_LENGTH);
 	if (ret != NULL)
@@ -1313,7 +1317,7 @@ static int __init amd_iommu_init(void)
 		ret = amd_iommu_init_dma_ops();
 
 	if (ret)
-		goto free;
+		goto free_disable;
 
 	amd_iommu_init_api();
 
@@ -1331,9 +1335,10 @@ static int __init amd_iommu_init(void)
 out:
 	return ret;
 
-free:
+free_disable:
 	disable_iommus();
 
+free:
 	amd_iommu_uninit_devices();
 
 	free_pages((unsigned long)amd_iommu_pd_alloc_bitmap,


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