[PATCH] thermal/netlink: Prevent Userspace Segmentation Fault by Adjusting UAPI Header

[Zhang Rui <rui.zhang@intel.com>]

The intel-lpmd tool [1], which uses the THERMAL_GENL_ATTR_CPU_CAPABILITY
attribute to receive HFI events from kernel space, encounters a
segmentation fault after commit 1773572863c4 ("thermal: netlink: Add the
commands and the events for the thresholds").

The issue arises because the THERMAL_GENL_ATTR_CPU_CAPABILITY raw value
was changed while intel_lpmd still uses the old value.

Although intel_lpmd can be updated to check the THERMAL_GENL_VERSION and
use the appropriate THERMAL_GENL_ATTR_CPU_CAPABILITY value, the commit
itself is questionable. The commit introduced a new element in the
middle of enum thermal_genl_attr, which affects many existing attributes
and introduces potential risks and unnecessary maintenance burdens for
userspace thermal netlink event users.

Solve the issue by moving the newly introduced
THERMAL_GENL_ATTR_TZ_PREV_TEMP attribute to the end of the
enum thermal_genl_attr. This ensures that all existing thermal generic
netlink attributes remain unaffected.

Link: https://github.com/intel/intel-lpmd [1]
Fixes: 1773572863c4 ("thermal: netlink: Add the commands and the events for the thresholds")
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
---
 include/uapi/linux/thermal.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/uapi/linux/thermal.h b/include/uapi/linux/thermal.h
index 349718c271eb..46a2633d33aa 100644
--- a/include/uapi/linux/thermal.h
+++ b/include/uapi/linux/thermal.h
@@ -30,7 +30,6 @@ enum thermal_genl_attr {
 	THERMAL_GENL_ATTR_TZ,
 	THERMAL_GENL_ATTR_TZ_ID,
 	THERMAL_GENL_ATTR_TZ_TEMP,
-	THERMAL_GENL_ATTR_TZ_PREV_TEMP,
 	THERMAL_GENL_ATTR_TZ_TRIP,
 	THERMAL_GENL_ATTR_TZ_TRIP_ID,
 	THERMAL_GENL_ATTR_TZ_TRIP_TYPE,
@@ -54,6 +53,7 @@ enum thermal_genl_attr {
 	THERMAL_GENL_ATTR_THRESHOLD,
 	THERMAL_GENL_ATTR_THRESHOLD_TEMP,
 	THERMAL_GENL_ATTR_THRESHOLD_DIRECTION,
+	THERMAL_GENL_ATTR_TZ_PREV_TEMP,
 	__THERMAL_GENL_ATTR_MAX,
 };
 #define THERMAL_GENL_ATTR_MAX (__THERMAL_GENL_ATTR_MAX - 1)
-- 
2.34.1