Commit 14c4acc5 authored by Joao Martins's avatar Joao Martins Committed by Joerg Roedel
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iommu/amd: Fix potential @entry null deref 



After commit 26e495f3 ("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: 26e495f3 ("iommu/amd: Restore IRTE.RemapEn bit after programming IRTE")
Reported-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: default avatarJoao Martins <joao.m.martins@oracle.com>
Reviewed-by: default avatarSuravee 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: default avatarJoerg Roedel <jroedel@suse.de>
parent 856deb86

drivers/iommu/amd/iommu.c

+3 −1
Original line number Diff line number Diff line
@@ -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;