thermal: core: Fix TZ_GET_TRIP NULL pointer dereference

stable inclusion
from stable-v5.10.104
commit 1c0b51e62a50e9291764d022ed44549e65d6ab9c
bugzilla: https://gitee.com/openeuler/kernel/issues/I56XAC

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=1c0b51e62a50e9291764d022ed44549e65d6ab9c

--------------------------------

commit 5838a148 upstream.

Do not call get_trip_hyst() from thermal_genl_cmd_tz_get_trip() if
the thermal zone does not define one.

Fixes: 1ce50e7d ("thermal: core: genetlink support for events/cmd/sampling")
Signed-off-by: NNicolas Cavallari <nicolas.cavallari@green-communications.fr>
Cc: 5.10+ <stable@vger.kernel.org> # 5.10+
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYu Liao <liaoyu15@huawei.com>
Reviewed-by: NWei Li <liwei391@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/thermal/thermal_netlink.c

@@ -418,11 +418,12 @@ static int thermal_genl_cmd_tz_get_trip(struct param *p)
 	for (i = 0; i < tz->trips; i++) {
 
 		enum thermal_trip_type type;
-		int temp, hyst;
+		int temp, hyst = 0;
 
 		tz->ops->get_trip_type(tz, i, &type);
 		tz->ops->get_trip_temp(tz, i, &temp);
-		tz->ops->get_trip_hyst(tz, i, &hyst);
+		if (tz->ops->get_trip_hyst)
+			tz->ops->get_trip_hyst(tz, i, &hyst);
 
 		if (nla_put_u32(msg, THERMAL_GENL_ATTR_TZ_TRIP_ID, i) ||
 		    nla_put_u32(msg, THERMAL_GENL_ATTR_TZ_TRIP_TYPE, type) ||