linux-kernel - [PATCH][next][V3] rtc: ds1307: check for failed memory allocation on wdt

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Date:   Fri,  3 Apr 2020 12:04:37 +0100
From:   Colin King <colin.king@...onical.com>
To:     Alessandro Zummo <a.zummo@...ertech.it>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Guenter Roeck <linux@...ck-us.net>,
        Chris Packham <chris.packham@...iedtelesis.co.nz>,
        linux-rtc@...r.kernel.org
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH][next][V3] rtc: ds1307: check for failed memory allocation on wdt

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

Currently a failed memory allocation will lead to a null pointer
dereference on point wdt.  Fix this by checking for a failed
allocation and just returning.

Addresses-Coverity: ("Dereference null return")
Fixes: fd90d48db037 ("rtc: ds1307: add support for watchdog timer on ds1388")

Signed-off-by: Colin Ian King <colin.king@...onical.com>
---

V2: move error exit label and remove a return statement, thanks to 
    Walter Harms for spotting this clean up.
V3: simplify, just bail out and return on detecting the out of memory
    condition

---

 drivers/rtc/rtc-ds1307.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
index fad042118862..49702942bb08 100644
--- a/drivers/rtc/rtc-ds1307.c
+++ b/drivers/rtc/rtc-ds1307.c
@@ -1673,6 +1673,8 @@ static void ds1307_wdt_register(struct ds1307 *ds1307)
 		return;
 
 	wdt = devm_kzalloc(ds1307->dev, sizeof(*wdt), GFP_KERNEL);
+	if (!wdt)
+		return;
 
 	wdt->info = &ds1388_wdt_info;
 	wdt->ops = &ds1388_wdt_ops;
-- 
2.25.1