cacheinfo: workaround cacheinfo's info_list uninitialized error

hulk inclusion
category: bugfix
bugzilla: 48265
CVE: NA

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

Workaround cacheinfo's info_list uninitialized error in some special
cases, such as free_cache_attributes() free info_list but not set
num_leaves to zero when PPTT is not supported. this solution lasts
until upstream issue resolved.

Fixes: 950e5edb ("drivers: base: cacheinfo: Add helper to search cacheinfo by of_node")
Fixes: 709c4362 ("cacheinfo: Move resctrl's get_cache_id() to the cacheinfo header file")
Signed-off-by: NWang ShaoBo <bobo.shaobowang@huawei.com>
Reviewed-by: NJian Cheng <cj.chengjian@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/base/cacheinfo.c

@@ -228,6 +228,8 @@ struct cacheinfo *cacheinfo_shared_cpu_map_search(void *fw_token)
 
 	for_each_online_cpu(cpu) {
 		cpu_ci = get_cpu_cacheinfo(cpu);
+		if (!cpu_ci->info_list)
+			continue;
 
 		for (index = 0; index < cache_leaves(cpu); index++) {
 			iter = cpu_ci->info_list + index;

include/linux/cacheinfo.h

@@ -131,6 +131,8 @@ static inline int get_cpu_cacheinfo_id(int cpu, int level)
 	int i;
 
 	for (i = 0; i < ci->num_leaves; i++) {
+		if (!ci->info_list)
+			continue;
 		if (ci->info_list[i].level == level) {
 			if (ci->info_list[i].attributes & CACHE_ID)
 				return ci->info_list[i].id;