linux-kernel - [PATCH 5/7] iommu/amd: Set global pointers to NULL after freeing them

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Date:   Fri, 16 Jun 2017 16:09:58 +0200
From:   Joerg Roedel <joro@...tes.org>
To:     iommu@...ts.linux-foundation.org
Cc:     linux-kernel@...r.kernel.org, Joerg Roedel <jroedel@...e.de>
Subject: [PATCH 5/7] iommu/amd: Set global pointers to NULL after freeing them

From: Joerg Roedel <jroedel@...e.de>

Avoid any tries to double-free these pointers.

Signed-off-by: Joerg Roedel <jroedel@...e.de>
---
 drivers/iommu/amd_iommu_init.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
index a31f375..d04898c 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -2112,18 +2112,22 @@ static void __init free_iommu_resources(void)
 	kmemleak_free(irq_lookup_table);
 	free_pages((unsigned long)irq_lookup_table,
 		   get_order(rlookup_table_size));
+	irq_lookup_table = NULL;
 
 	kmem_cache_destroy(amd_iommu_irq_cache);
 	amd_iommu_irq_cache = NULL;
 
 	free_pages((unsigned long)amd_iommu_rlookup_table,
 		   get_order(rlookup_table_size));
+	amd_iommu_rlookup_table = NULL;
 
 	free_pages((unsigned long)amd_iommu_alias_table,
 		   get_order(alias_table_size));
+	amd_iommu_alias_table = NULL;
 
 	free_pages((unsigned long)amd_iommu_dev_table,
 		   get_order(dev_table_size));
+	amd_iommu_dev_table = NULL;
 
 	free_iommu_all();
 
@@ -2193,6 +2197,7 @@ static void __init free_dma_resources(void)
 {
 	free_pages((unsigned long)amd_iommu_pd_alloc_bitmap,
 		   get_order(MAX_DOMAIN_ID/8));
+	amd_iommu_pd_alloc_bitmap = NULL;
 
 	free_unity_maps();
 }
-- 
2.7.4