linux-kernel - [PATCH v1] OPP: Fix crashing when current OPP has unsupportable voltage

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Message-Id: <20190623175053.26167-1-digetx@gmail.com>
Date:   Sun, 23 Jun 2019 20:50:53 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Viresh Kumar <vireshk@...nel.org>, Nishanth Menon <nm@...com>,
        Stephen Boyd <sboyd@...nel.org>,
        Marc Dietrich <marvin24@....de>
Cc:     linux-pm@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v1] OPP: Fix crashing when current OPP has unsupportable voltage

Fix NULL dereference caused by a typo in the code. In particular it
happens when CPU is running on a frequency which has unsupportable voltage
(by regulator) defined in the OPP table and a custom set_opp() callback is
being used. The problem was spotted during of testing of upcoming update
for the NVIDIA Tegra CPUFreq driver.

Cc: stable <stable@...r.kernel.org>
Fixes: 7e535993fa4f ("OPP: Separate out custom OPP handler specific code")
Reported-by: Marc Dietrich <marvin24@....de>
Signed-off-by: Dmitry Osipenko <digetx@...il.com>
---
 drivers/opp/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index 9fda9a0ec016..89ec6aa220cf 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -685,7 +685,7 @@ static int _set_opp_custom(const struct opp_table *opp_table,
 
 	data->old_opp.rate = old_freq;
 	size = sizeof(*old_supply) * opp_table->regulator_count;
-	if (IS_ERR(old_supply))
+	if (!old_supply)
 		memset(data->old_opp.supplies, 0, size);
 	else
 		memcpy(data->old_opp.supplies, old_supply, size);
-- 
2.22.0