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From:   Samuel Holland <samuel@sholland.org>
To:     MyungJoo Ham <myungjoo.ham@samsung.com>,
        Kyungmin Park <kyungmin.park@samsung.com>,
        Chanwoo Choi <cw00.choi@samsung.com>,
        Maxime Ripard <mripard@kernel.org>,
        Chen-Yu Tsai <wens@csie.org>,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        Rob Herring <robh+dt@kernel.org>
Cc:     Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-pm@vger.kernel.org,
        linux-sunxi@lists.linux.dev, linux-kernel@vger.kernel.org,
        Samuel Holland <samuel@sholland.org>
Subject: [PATCH 01/10] PM / devfreq: strengthen check for freq_table
Date:   Tue, 28 Sep 2021 23:42:45 -0500
Message-Id: <20210929044254.38301-2-samuel@sholland.org>
In-Reply-To: <20210929044254.38301-1-samuel@sholland.org>
References: <20210929044254.38301-1-samuel@sholland.org>
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Since commit ea572f816032 ("PM / devfreq: Change return type of
devfreq_set_freq_table()"), all devfreq devices are expected to have a
valid freq_table. The devfreq core unconditionally dereferences
freq_table in the sysfs code and in get_freq_range().

Therefore, we need to ensure that freq_table is both non-null and
non-empty (length is > 0). If either check fails, replace the table
using set_freq_table() or return the error.

Signed-off-by: Samuel Holland <samuel@sholland.org>
---
 drivers/devfreq/devfreq.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 28f3e0ba6cdd..7a8b022ba456 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -827,7 +827,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
 		goto err_dev;
 	}
 
-	if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
+	if (!devfreq->profile->max_state || !devfreq->profile->freq_table) {
 		mutex_unlock(&devfreq->lock);
 		err = set_freq_table(devfreq);
 		if (err < 0)
-- 
2.31.1