Messages in this thread Patch in this message | | | From | Joao Martins <> | Subject | [PATCH] iommu/amd: Fix potential @entry null deref | Date | Thu, 10 Sep 2020 18:16:21 +0100 |
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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.
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> 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> --- 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 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; -- 2.17.1
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