linux-kernel - [PATCH] OMAP: iommu: check for failure of a call to omap_iommu_dump

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Message-Id: <20200714192211.744776-1-colin.king@canonical.com>
Date:   Tue, 14 Jul 2020 20:22:11 +0100
From:   Colin King <colin.king@...onical.com>
To:     Joerg Roedel <joro@...tes.org>, Tony Lindgren <tony@...mide.com>,
        Hiroshi DOYU <Hiroshi.DOYU@...ia.com>,
        iommu@...ts.linux-foundation.org
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] OMAP: iommu: check for failure of a call to omap_iommu_dump_ctx

From: Colin Ian King <colin.king@...onical.com>

It is possible for the call to omap_iommu_dump_ctx to return
a negative error number, so check for the failure and return
the error number rather than pass the negative value to
simple_read_from_buffer.

Addresses-Coverity: ("Improper use of negative value")
Fixes: 14e0e6796a0d ("OMAP: iommu: add initial debugfs support")
Signed-off-by: Colin Ian King <colin.king@...onical.com>
---
 drivers/iommu/omap-iommu-debug.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/iommu/omap-iommu-debug.c b/drivers/iommu/omap-iommu-debug.c
index 8e19bfa94121..a99afb5d9011 100644
--- a/drivers/iommu/omap-iommu-debug.c
+++ b/drivers/iommu/omap-iommu-debug.c
@@ -98,8 +98,11 @@ static ssize_t debug_read_regs(struct file *file, char __user *userbuf,
 	mutex_lock(&iommu_debug_lock);
 
 	bytes = omap_iommu_dump_ctx(obj, p, count);
+	if (bytes < 0)
+		goto err;
 	bytes = simple_read_from_buffer(userbuf, count, ppos, buf, bytes);
 
+err:
 	mutex_unlock(&iommu_debug_lock);
 	kfree(buf);
 
-- 
2.27.0