From 4378d99295fae5fd42b0ed1a3eeef2a1684e0c17 Mon Sep 17 00:00:00 2001
From: Jay Cornwall <jay.cornwall@amd.com>
Date: Mon, 28 Apr 2014 17:27:46 -0500
Subject: [PATCH] iommu/amd: Take mmap_sem when calling get_user_pages
get_user_pages requires caller to hold a read lock on mmap_sem.
Signed-off-by: Jay Cornwall <jay.cornwall@amd.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Joerg Roedel <joro@8bytes.org>
---
drivers/iommu/amd_iommu_v2.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c
index 5208828792e60..203b2e6a91cfc 100644
--- a/drivers/iommu/amd_iommu_v2.c
+++ b/drivers/iommu/amd_iommu_v2.c
@@ -504,8 +504,10 @@ static void do_fault(struct work_struct *work)
write = !!(fault->flags & PPR_FAULT_WRITE);
+ down_read(&fault->state->mm->mmap_sem);
npages = get_user_pages(fault->state->task, fault->state->mm,
fault->address, 1, write, 0, &page, NULL);
+ up_read(&fault->state->mm->mmap_sem);
if (npages == 1) {
put_page(page);
--
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