Re: [PATCH v2] clk: Skip clk provider registration when np is NULL
From: Nathan Chancellor <nathan@kernel.org>
Date: 2021-05-10 20:20:57
Also in:
linux-acpi, linux-clk, linux-devicetree, linux-doc, lkml
On Mon, Apr 26, 2021 at 09:56:18AM +0300, Tudor Ambarus wrote:
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_hw_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")
Fixes: 3c9ea42802a1 ("clk: Mark fwnodes when their clock provider is added/removed")
Signed-off-by: Tudor Ambarus <redacted>
Reviewed-by: Stephen Boyd <sboyd@kernel.org>Tested-by: Nathan Chancellor <nathan@kernel.org>
quoted hunk ↗ jump to hunk
--- v2: - s/return 0;/return; in void of_clk_del_provider() - add second fixes tag and Stephen's R-b tag The opinions on whether to return an error or zero were split. Returning 0 and skipping the logic was considered safer as we don't know for sure if other drivers are affected. See: https://lore.kernel.org/lkml/d24bebc5-0f78-021f-293f-e58defa32531@samsung.com/ (local) https://lore.kernel.org/lkml/20210423171335.262316-1-tudor.ambarus@microchip.com/ (local) drivers/clk/clk.c | 9 +++++++++ 1 file changed, 9 insertions(+)diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index a3b30f7de2ef..b47460b40d14 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c@@ -4552,6 +4552,9 @@ 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;@@ -4591,6 +4594,9 @@ 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;@@ -4688,6 +4694,9 @@ void of_clk_del_provider(struct device_node *np) { struct of_clk_provider *cp; + if (!np) + return; + mutex_lock(&of_clk_mutex); list_for_each_entry(cp, &of_clk_providers, link) { if (cp->node == np) {-- 2.25.1