| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.4 48/72] iommu/amd: Fix potential @entry null deref | Date | Mon, 21 Sep 2020 18:31:27 +0200 |
| |
From: Joao Martins <joao.m.martins@oracle.com>
[ 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> --- drivers/iommu/amd_iommu.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c index cdafc652d9d1a..fa91d856a43ee 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; -- 2.25.1
|