From: Tudor Ambarus <tudor.ambarus@microchip.com>
To: <mturquette@baylibre.com>, <sboyd@kernel.org>,
<nsaenz@kernel.org>, <maxime@cerno.tech>,
<gregkh@linuxfoundation.org>, <rafael@kernel.org>,
<khilman@kernel.org>, <ulf.hansson@linaro.org>,
<len.brown@intel.com>, <pavel@ucw.cz>, <robh+dt@kernel.org>,
<frowand.list@gmail.com>, <maz@kernel.org>, <tglx@linutronix.de>,
<saravanak@google.com>, <geert@linux-m68k.org>,
<nsaenzjulienne@suse.de>, <linux@roeck-us.net>,
<guillaume.tucker@collabora.com>
Cc: <linux-clk@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<corbet@lwn.net>, <nicolas.ferre@microchip.com>,
<claudiu.beznea@microchip.com>, <linux-doc@vger.kernel.org>,
<linux-pm@vger.kernel.org>, <devicetree@vger.kernel.org>,
<linux-acpi@vger.kernel.org>, <kernel-team@android.com>,
<linux-rpi-kernel@lists.infradead.org>,
Tudor Ambarus <tudor.ambarus@microchip.com>,
Marek Szyprowski <m.szyprowski@samsung.com>
Subject: [PATCH] clk: Skip clk provider registration when np is NULL
Date: Fri, 23 Apr 2021 22:12:36 +0300 [thread overview]
Message-ID: <20210423191236.265996-1-tudor.ambarus@microchip.com> (raw)
In-Reply-To: <20210423171335.262316-1-tudor.ambarus@microchip.com>
commit 6579c8d97ad7 ("clk: Mark fwnodes when their clock provider is added")
revealed that clk/bcm/clk-raspberrypi.c driver calls
devm_of_clk_add_hw_provider(), with a NULL dev->of_node, which resulted in a
NULL pointer dereference in of_clk_add_provider() when calling
fwnode_dev_initialized().
Returning 0 is reducing the if conditions in driver code and is being
consistent with the CONFIG_OF=n inline stub that returns 0 when CONFIG_OF
is disabled. The downside is that drivers will maybe register clkdev lookups
when they don't need to and waste some memory.
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Fixes: 6579c8d97ad7 ("clk: Mark fwnodes when their clock provider is added")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
---
This would be the second approach, where we don't return an error when
one calls devm_of_clk_add_hw_provider with a NULL of_node, but instead
we just return 0 and skip the logic in the core and the drivers.
drivers/clk/clk.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index e2ec1b745243..5d10da3519ac 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -4540,6 +4540,9 @@ int of_clk_add_provider(struct device_node *np,
struct of_clk_provider *cp;
int ret;
+ if (!np)
+ return 0;
+
cp = kzalloc(sizeof(*cp), GFP_KERNEL);
if (!cp)
return -ENOMEM;
@@ -4579,6 +4582,9 @@ int of_clk_add_hw_provider(struct device_node *np,
struct of_clk_provider *cp;
int ret;
+ if (!np)
+ return 0;
+
cp = kzalloc(sizeof(*cp), GFP_KERNEL);
if (!cp)
return -ENOMEM;
@@ -4676,6 +4682,9 @@ void of_clk_del_provider(struct device_node *np)
{
struct of_clk_provider *cp;
+ if (!np)
+ return 0;
+
mutex_lock(&of_clk_mutex);
list_for_each_entry(cp, &of_clk_providers, link) {
if (cp->node == np) {
--
2.25.1
next prev parent reply other threads:[~2021-04-23 19:12 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-23 17:13 [PATCH 0/2] clk: Do not register provider with a NULL dev->of_node Tudor Ambarus
2021-04-23 17:13 ` [PATCH 1/2] " Tudor Ambarus
2021-04-23 17:24 ` Saravana Kannan
2021-04-23 18:21 ` nicolas saenz julienne
2021-04-23 18:35 ` Tudor.Ambarus
2021-04-23 17:13 ` [PATCH 2/2] clk: bcm: rpi: Do not call devm_of_clk_add_hw_provider " Tudor Ambarus
2021-04-23 19:12 ` Tudor Ambarus [this message]
2021-04-23 19:16 ` [PATCH] clk: Skip clk provider registration when np is NULL Tudor.Ambarus
2021-04-24 1:17 ` Stephen Boyd
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