powercap: intel_rapl: Fix a NULL pointer dereference

A NULL pointer dereference is triggered when probing the MMIO RAPL
driver on platforms with CPU ID not listed in intel_rapl_common CPU
model list.

This is because the intel_rapl_common module still probes on such
platforms even if 'defaults_msr' is not set after commit 1488ac990ac8
("powercap: intel_rapl: Allow probing without CPUID match"). Thus the
MMIO RAPL rp->priv->defaults is NULL when registering to RAPL framework.

Fix the problem by adding sanity check to ensure rp->priv->rapl_defaults
is always valid.

Fixes: 1488ac990ac8 ("powercap: intel_rapl: Allow probing without CPUID match")
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Cc: 6.5+ <stable@vger.kernel.org> # 6.5+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/powercap/intel_rapl_common.c b/drivers/powercap/intel_rapl_common.c
index 2feed036c1cd415ef98a7ea3437ebd5bc7429b10..1a739afd47d965aac064b531237c9f166f938e86 100644 (file)
--- a/drivers/powercap/intel_rapl_common.c
+++ b/drivers/powercap/intel_rapl_common.c
@@ -759,6 +759,11 @@ static int rapl_config(struct rapl_package *rp)
        default:
                return -EINVAL;
        }
+
+       /* defaults_msr can be NULL on unsupported platforms */
+       if (!rp->priv->defaults || !rp->priv->rpi)
+               return -ENODEV;
+
        return 0;
 }