linux-kernel - [PATCH] iommu/riscv: Fix unsigned comparison with negative error code

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Message-ID: <20251222151550.987992-1-alperyasinak1@gmail.com>
Date: Mon, 22 Dec 2025 18:15:49 +0300
From: Alper Ak <alperyasinak1@...il.com>
To: tjeznach@...osinc.com
Cc: Alper Ak <alperyasinak1@...il.com>,
	Dan Carpenter <error27@...il.com>,
	Joerg Roedel <joro@...tes.org>,
	Will Deacon <will@...nel.org>,
	Robin Murphy <robin.murphy@....com>,
	Paul Walmsley <pjw@...nel.org>,
	Palmer Dabbelt <palmer@...belt.com>,
	Albert Ou <aou@...s.berkeley.edu>,
	Alexandre Ghiti <alex@...ti.fr>,
	iommu@...ts.linux.dev,
	linux-riscv@...ts.infradead.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] iommu/riscv: Fix unsigned comparison with negative error code

platform_irq_count() can return -EPROBE_DEFER, but irqs_count is
unsigned. This causes the negative value to wrap around and bypass
the error check.

Store the return value in a signed integer first and check for
errors before assigning to irqs_count.

Reported-by: Dan Carpenter <error27@...il.com>
Closes: https://lore.kernel.org/r/202512141551.kZLTle5r-lkp@intel.com/
Signed-off-by: Alper Ak <alperyasinak1@...il.com>
---
 drivers/iommu/riscv/iommu-platform.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/riscv/iommu-platform.c b/drivers/iommu/riscv/iommu-platform.c
index 83a28c83f991..5ec8efedbf12 100644
--- a/drivers/iommu/riscv/iommu-platform.c
+++ b/drivers/iommu/riscv/iommu-platform.c
@@ -68,8 +68,13 @@ static int riscv_iommu_platform_probe(struct platform_device *pdev)
 	iommu->caps = riscv_iommu_readq(iommu, RISCV_IOMMU_REG_CAPABILITIES);
 	iommu->fctl = riscv_iommu_readl(iommu, RISCV_IOMMU_REG_FCTL);
 
-	iommu->irqs_count = platform_irq_count(pdev);
-	if (iommu->irqs_count <= 0)
+	ret = platform_irq_count(pdev);
+	if (ret < 0)
+		return ret;
+
+	iommu->irqs_count = ret;
+
+	if (!iommu->irqs_count)
 		return dev_err_probe(dev, -ENODEV,
 				     "no IRQ resources provided\n");
 	if (iommu->irqs_count > RISCV_IOMMU_INTR_COUNT)
-- 
2.43.0