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authorJoao Martins <joao.m.martins@oracle.com>2020-09-10 18:16:21 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-09-23 12:40:42 +0200
commita55eec14a4e1987f5415b523bd67355ab0186497 (patch)
tree8cf80dece985d0f1ef815e7915570205bbf232bf
parentecd219c72945d531b68916711d1e67f0e20d94da (diff)
iommu/amd: Fix potential @entry null deref
[ Upstream commit 14c4acc5ed22c21f9821103be7c48efdf9763584 ] After commit 26e495f34107 ("iommu/amd: Restore IRTE.RemapEn bit after programming IRTE"), smatch warns: drivers/iommu/amd/iommu.c:3870 amd_iommu_deactivate_guest_mode() warn: variable dereferenced before check 'entry' (see line 3867) Fix this by moving the @valid assignment to after @entry has been checked for NULL. Fixes: 26e495f34107 ("iommu/amd: Restore IRTE.RemapEn bit after programming IRTE") Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Joao Martins <joao.m.martins@oracle.com> Reviewed-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Link: https://lore.kernel.org/r/20200910171621.12879-1-joao.m.martins@oracle.com Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Sasha Levin <sashal@kernel.org>
-rw-r--r--drivers/iommu/amd_iommu.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index cdafc652d9d1..fa91d856a43e 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -4431,12 +4431,14 @@ int amd_iommu_deactivate_guest_mode(void *data)
struct amd_ir_data *ir_data = (struct amd_ir_data *)data;
struct irte_ga *entry = (struct irte_ga *) ir_data->entry;
struct irq_cfg *cfg = ir_data->cfg;
- u64 valid = entry->lo.fields_remap.valid;
+ u64 valid;
if (!AMD_IOMMU_GUEST_IR_VAPIC(amd_iommu_guest_ir) ||
!entry || !entry->lo.fields_vapic.guest_mode)
return 0;
+ valid = entry->lo.fields_remap.valid;
+
entry->lo.val = 0;
entry->hi.val = 0;