[PATCH 5.15.y] arch_topology: Fix incorrect error check in topology_parse_cpu_capacity()

[Sasha Levin <sashal@kernel.org>]

From: Kaushlendra Kumar <kaushlendra.kumar@intel.com>

[ Upstream commit 2eead19334516c8e9927c11b448fbe512b1f18a1 ]

Fix incorrect use of PTR_ERR_OR_ZERO() in topology_parse_cpu_capacity()
which causes the code to proceed with NULL clock pointers. The current
logic uses !PTR_ERR_OR_ZERO(cpu_clk) which evaluates to true for both
valid pointers and NULL, leading to potential NULL pointer dereference
in clk_get_rate().

Per include/linux/err.h documentation, PTR_ERR_OR_ZERO(ptr) returns:
"The error code within @ptr if it is an error pointer; 0 otherwise."

This means PTR_ERR_OR_ZERO() returns 0 for both valid pointers AND NULL
pointers. Therefore !PTR_ERR_OR_ZERO(cpu_clk) evaluates to true (proceed)
when cpu_clk is either valid or NULL, causing clk_get_rate(NULL) to be
called when of_clk_get() returns NULL.

Replace with !IS_ERR_OR_NULL(cpu_clk) which only proceeds for valid
pointers, preventing potential NULL pointer dereference in clk_get_rate().

Cc: stable <stable@kernel.org>
Signed-off-by: Kaushlendra Kumar <kaushlendra.kumar@intel.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Fixes: b8fe128dad8f ("arch_topology: Adjust initial CPU capacities with current freq")
Link: https://patch.msgid.link/20250923174308.1771906-1-kaushlendra.kumar@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Adjust context ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/base/arch_topology.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
index 31bd6f4e5dc47..69dea9825f6a5 100644
--- a/drivers/base/arch_topology.c
+++ b/drivers/base/arch_topology.c
@@ -290,7 +290,7 @@ bool __init topology_parse_cpu_capacity(struct device_node *cpu_node, int cpu)
 		 * frequency (by keeping the initial freq_factor value).
 		 */
 		cpu_clk = of_clk_get(cpu_node, 0);
-		if (!PTR_ERR_OR_ZERO(cpu_clk)) {
+		if (!IS_ERR_OR_NULL(cpu_clk)) {
 			per_cpu(freq_factor, cpu) =
 				clk_get_rate(cpu_clk) / 1000;
 			clk_put(cpu_clk);
-- 
2.51.0