From: Joao Martins Date: Thu, 10 Sep 2020 17:16:21 +0000 (+0100) Subject: iommu/amd: Fix potential @entry null deref X-Git-Tag: v5.9-rc6~22^2~1 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=14c4acc5ed22c21f9821103be7c48efdf9763584;p=linux-2.6-block.git iommu/amd: Fix potential @entry null deref 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 Signed-off-by: Joao Martins Reviewed-by: Suravee Suthikulpanit Cc: Suravee Suthikulpanit Link: https://lore.kernel.org/r/20200910171621.12879-1-joao.m.martins@oracle.com Signed-off-by: Joerg Roedel --- diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c index 07ae8b93887e..8abe1c7ad45b 100644 --- a/drivers/iommu/amd/iommu.c +++ b/drivers/iommu/amd/iommu.c @@ -3864,12 +3864,14 @@ 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;