Commit 014d6e75 authored Dec 23, 2020 by Manaf Meethalavalappu Pallikunhi Committed by Gerrit - the friendly Code Review server Jan 19, 2021

drivers: thermal: Use lock before accessing thermal instance list



The thermal zone config read callback is not holding lock before
accessing thermal instance list. There is a chance that both cooling
device binding and thermal zone config show read are happening
concurrently. The cooling device binding tries to add new thermal
instances and the same time thermal zone config show read context
tries to access thermal instance list. It leads to unexpected
behaviour.

Use lock before accessing thermal instance list in thermal zone
config read callback.

Change-Id: I1bea07cb67a7240027dd34cea2ff61def9258b8f
Signed-off-by: Manaf Meethalavalappu Pallikunhi <manafm@codeaurora.org>

parent 9ddceddf

drivers/thermal/thermal_sysfs.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -107,12 +107,16 @@ config_show(struct device dev, struct device_attribute attr, char *buf)
		buf_offset = 0;
		buf1_offset = 0;
		buf2_offset = 0;

		mutex_lock(&tz->lock);
		list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
		if (instance->cdev)
		buf_size++;
		}
		if (!buf_size)
		if (!buf_size) {
		mutex_unlock(&tz->lock);
		goto config_exit;
		}
		buf_size *= THERMAL_NAME_LENGTH;
		buf_cdev = kzalloc(buf_size, GFP_KERNEL);
		buf_cdev_upper = kzalloc(buf_size, GFP_KERNEL);
		@@ -153,6 +157,8 @@ config_show(struct device dev, struct device_attribute attr, char *buf)
		}
		}
		}
		mutex_unlock(&tz->lock);

		offset += scnprintf(buf + offset, PAGE_SIZE - offset,
		"device %s\n", buf_cdev);
		offset += scnprintf(buf + offset, PAGE_SIZE - offset,