linux-kernel - [PATCH 2/3] x86/amd-iommu: Fix crash when request_mem

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Date:	Tue, 1 Jun 2010 11:03:40 +0200
From:	Joerg Roedel <joerg.roedel@....com>
To:	Ingo Molnar <mingo@...e.hu>
CC:	<iommu@...ts.linux-foundation.org>, <linux-kernel@...r.kernel.org>,
	Joerg Roedel <joerg.roedel@....com>, <stable@...nel.org>
Subject: [PATCH 2/3] x86/amd-iommu: Fix crash when request_mem_region fails

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.

Cc: stable@...nel.org
Signed-off-by: Joerg Roedel <joerg.roedel@....com>
---
 arch/x86/kernel/amd_iommu_init.c |   11 ++++++++---
 1 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index 3bacb4d..1405346 100644
--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -287,8 +287,12 @@ static u8 * __init iommu_map_mmio_space(u64 address)
 {
 	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)
@@ -1314,7 +1318,7 @@ static int __init amd_iommu_init(void)
 		ret = amd_iommu_init_dma_ops();
 
 	if (ret)
-		goto free;
+		goto free_disable;
 
 	amd_iommu_init_api();
 
@@ -1332,9 +1336,10 @@ 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,
-- 
1.7.1


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