linux-kernel - [PATCH][next] cxl/core: Fix a deference of a pointer cxl

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Date:   Sun, 29 Aug 2021 18:15:53 +0100
From:   Colin King <colin.king@...onical.com>
To:     Alison Schofield <alison.schofield@...el.com>,
        Vishal Verma <vishal.l.verma@...el.com>,
        Ira Weiny <ira.weiny@...el.com>,
        Ben Widawsky <ben.widawsky@...el.com>,
        Dan Williams <dan.j.williams@...el.com>,
        Jonathan Cameron <Jonathan.Cameron@...wei.com>,
        linux-cxl@...r.kernel.org
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH][next] cxl/core: Fix a deference of a pointer cxl_port before it is null checked

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

The assignment of pointer port with a dereference of pointer cxl_port
occurs before cxl_port is null checked. Fix this by only assigning port
once cxl_port has been null checked.

Addresses-Coverity: ("Dereference before null check")
Fixes: b7ca54b62551 ("cxl/core: Split decoder setup into alloc + add")
Signed-off-by: Colin Ian King <colin.king@...onical.com>
---
 drivers/cxl/core/bus.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/cxl/core/bus.c b/drivers/cxl/core/bus.c
index 0b85351be6bf..55db46ba8a18 100644
--- a/drivers/cxl/core/bus.c
+++ b/drivers/cxl/core/bus.c
@@ -494,7 +494,7 @@ EXPORT_SYMBOL_GPL(cxl_decoder_alloc);
 int devm_cxl_add_decoder(struct device *host, struct cxl_decoder *cxld,
 			 int *target_map)
 {
-	struct cxl_port *port = to_cxl_port(cxld->dev.parent);
+	struct cxl_port *port;
 	struct device *dev;
 	int rc = 0, i;
 
@@ -509,6 +509,7 @@ int devm_cxl_add_decoder(struct device *host, struct cxl_decoder *cxld,
 		goto err;
 	}
 
+	port = to_cxl_port(cxld->dev.parent);
 	device_lock(&port->dev);
 	if (list_empty(&port->dports))
 		rc = -EINVAL;
-- 
2.32.0