linux-kernel - [tip: x86/irq] iommu/amd: Prevent NULL pointer dereference

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Date:   Wed, 16 Sep 2020 15:12:29 -0000
From:   "tip-bot2 for Thomas Gleixner" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Joerg Roedel <jroedel@...e.de>, x86 <x86@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: [tip: x86/irq] iommu/amd: Prevent NULL pointer dereference

The following commit has been merged into the x86/irq branch of tip:

Commit-ID:     23357b61f8062a8a8c9c84c0252056cd6d849ec8
Gitweb:        https://git.kernel.org/tip/23357b61f8062a8a8c9c84c0252056cd6d849ec8
Author:        Thomas Gleixner <tglx@...utronix.de>
AuthorDate:    Wed, 26 Aug 2020 13:16:29 +02:00
Committer:     Thomas Gleixner <tglx@...utronix.de>
CommitterDate: Wed, 16 Sep 2020 16:52:25 +02:00

iommu/amd: Prevent NULL pointer dereference

Dereferencing irq_data before checking it for NULL is suboptimal.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Reviewed-by: Joerg Roedel <jroedel@...e.de>

---
 drivers/iommu/amd/iommu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index 07ae8b9..db44ce6 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -3731,8 +3731,8 @@ static int irq_remapping_alloc(struct irq_domain *domain, unsigned int virq,
 
 	for (i = 0; i < nr_irqs; i++) {
 		irq_data = irq_domain_get_irq_data(domain, virq + i);
-		cfg = irqd_cfg(irq_data);
-		if (!irq_data || !cfg) {
+		cfg = irq_data ? irqd_cfg(irq_data) : NULL;
+		if (!cfg) {
 			ret = -EINVAL;
 			goto out_free_data;
 		}