Re: [PATCH v2][next] wifi: iwlwifi: mvm: Use __counted_by() and avoid -Wfamnae warnings

["Gustavo A. R. Silva" <gustavo@embeddedor.com>]

On 10/08/24 22:26, kernel test robot wrote:
> Hi Gustavo,
> 
> kernel test robot noticed the following build errors:
> 
> [auto build test ERROR on wireless-next/main]
> [also build test ERROR on wireless/main linus/master v6.11-rc2 next-20240809]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
> 
> url:    https://github.com/intel-lab-lkp/linux/commits/Gustavo-A-R-Silva/wifi-iwlwifi-mvm-Use-__counted_by-and-avoid-Wfamnae-warnings/20240810-103759
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/wireless/wireless-next.git main
> patch link:    https://lore.kernel.org/r/ZrZs5KL5Pz9tIinr%40cute
> patch subject: [PATCH v2][next] wifi: iwlwifi: mvm: Use __counted_by() and avoid -Wfamnae warnings
> config: riscv-allmodconfig (https://download.01.org/0day-ci/archive/20240811/202408110634.V68RFEtW-lkp@intel.com/config)
> compiler: clang version 20.0.0git (https://github.com/llvm/llvm-project f86594788ce93b696675c94f54016d27a6c21d18)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240811/202408110634.V68RFEtW-lkp@intel.com/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202408110634.V68RFEtW-lkp@intel.com/
> 
> All errors (new ones prefixed by >>):
> 
>     In file included from drivers/net/wireless/intel/iwlwifi/mvm/d3.c:7:
>     In file included from include/linux/etherdevice.h:20:
>     In file included from include/linux/if_ether.h:19:
>     In file included from include/linux/skbuff.h:17:
>     In file included from include/linux/bvec.h:10:
>     In file included from include/linux/highmem.h:8:
>     In file included from include/linux/cacheflush.h:5:
>     In file included from arch/riscv/include/asm/cacheflush.h:9:
>     In file included from include/linux/mm.h:2228:
>     include/linux/vmstat.h:500:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
>       500 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
>           |                            ~~~~~~~~~~~~~~~~~~~~~ ^
>       501 |                            item];
>           |                            ~~~~
>     include/linux/vmstat.h:507:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
>       507 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
>           |                            ~~~~~~~~~~~~~~~~~~~~~ ^
>       508 |                            NR_VM_NUMA_EVENT_ITEMS +
>           |                            ~~~~~~~~~~~~~~~~~~~~~~
>     include/linux/vmstat.h:514:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
>       514 |         return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
>           |                               ~~~~~~~~~~~ ^ ~~~
>     include/linux/vmstat.h:519:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
>       519 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
>           |                            ~~~~~~~~~~~~~~~~~~~~~ ^
>       520 |                            NR_VM_NUMA_EVENT_ITEMS +
>           |                            ~~~~~~~~~~~~~~~~~~~~~~
>     include/linux/vmstat.h:528:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
>       528 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
>           |                            ~~~~~~~~~~~~~~~~~~~~~ ^
>       529 |                            NR_VM_NUMA_EVENT_ITEMS +
>           |                            ~~~~~~~~~~~~~~~~~~~~~~
>>> drivers/net/wireless/intel/iwlwifi/mvm/d3.c:2149:2: error: call to '__compiletime_assert_1044' declared with 'error' attribute: BUILD_BUG_ON failed: conf->keylen < WLAN_KEY_LEN_GCMP_256
>      2149 |         BUILD_BUG_ON(conf->keylen < WLAN_KEY_LEN_GCMP_256);
>           |         ^
>     include/linux/build_bug.h:50:2: note: expanded from macro 'BUILD_BUG_ON'
>        50 |         BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
>           |         ^
>     include/linux/build_bug.h:39:37: note: expanded from macro 'BUILD_BUG_ON_MSG'
>        39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
>           |                                     ^
>     include/linux/compiler_types.h:510:2: note: expanded from macro 'compiletime_assert'
>       510 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>           |         ^
>     include/linux/compiler_types.h:498:2: note: expanded from macro '_compiletime_assert'
>       498 |         __compiletime_assert(condition, msg, prefix, suffix)
>           |         ^
>     include/linux/compiler_types.h:491:4: note: expanded from macro '__compiletime_assert'
>       491 |                         prefix ## suffix();                             \
>           |                         ^
>     <scratch space>:38:1: note: expanded from here
>        38 | __compiletime_assert_1044
>           | ^
>>> drivers/net/wireless/intel/iwlwifi/mvm/d3.c:2148:2: error: call to '__compiletime_assert_1043' declared with 'error' attribute: BUILD_BUG_ON failed: conf->keylen < WLAN_KEY_LEN_CCMP
>      2148 |         BUILD_BUG_ON(conf->keylen < WLAN_KEY_LEN_CCMP);
>           |         ^
>     include/linux/build_bug.h:50:2: note: expanded from macro 'BUILD_BUG_ON'
>        50 |         BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
>           |         ^
>     include/linux/build_bug.h:39:37: note: expanded from macro 'BUILD_BUG_ON_MSG'
>        39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
>           |                                     ^
>     include/linux/compiler_types.h:510:2: note: expanded from macro 'compiletime_assert'
>       510 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>           |         ^
>     include/linux/compiler_types.h:498:2: note: expanded from macro '_compiletime_assert'
>       498 |         __compiletime_assert(condition, msg, prefix, suffix)
>           |         ^
>     include/linux/compiler_types.h:491:4: note: expanded from macro '__compiletime_assert'
>       491 |                         prefix ## suffix();                             \
>           |                         ^
>     <scratch space>:34:1: note: expanded from here
>        34 | __compiletime_assert_1043
>           | ^
>     5 warnings and 2 errors generated.
> 
> 
> vim +2149 drivers/net/wireless/intel/iwlwifi/mvm/d3.c
> 
>    2134	
>    2135	static bool iwl_mvm_gtk_rekey(struct iwl_wowlan_status_data *status,
>    2136				      struct ieee80211_vif *vif,
>    2137				      struct iwl_mvm *mvm, u32 gtk_cipher)
>    2138	{
>    2139		int i, j;
>    2140		struct ieee80211_key_conf *key;
>    2141		DEFINE_FLEX(struct ieee80211_key_conf, conf, key, keylen,
>    2142			    WOWLAN_KEY_MAX_SIZE);
>    2143		int link_id = vif->active_links ? __ffs(vif->active_links) : -1;


Holy molly guaca-guaca... swapping the above two lines fixes the issue:

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/d3.c b/drivers/net/wireless/intel/iwlwifi/mvm/d3.c
index 581455ab5e6d..764580cf6c58 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/d3.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/d3.c
@@ -2138,9 +2138,8 @@ static bool iwl_mvm_gtk_rekey(struct iwl_wowlan_status_data *status,
  {
         int i, j;
         struct ieee80211_key_conf *key;
-       DEFINE_FLEX(struct ieee80211_key_conf, conf, key, keylen,
-                   WOWLAN_KEY_MAX_SIZE);
         int link_id = vif->active_links ? __ffs(vif->active_links) : -1;
+       DEFINE_FLEX(struct ieee80211_key_conf, conf, key, keylen, WOWLAN_KEY_MAX_SIZE);

         conf->cipher = gtk_cipher;


This is the first time I've seen this compiler behavior when building DEFINE_FLEX() changes...

--
Gustavo

>    2144	
>    2145		conf->cipher = gtk_cipher;
>    2146	
>    2147		BUILD_BUG_ON(WLAN_KEY_LEN_CCMP != WLAN_KEY_LEN_GCMP);
>> 2148		BUILD_BUG_ON(conf->keylen < WLAN_KEY_LEN_CCMP);
>> 2149		BUILD_BUG_ON(conf->keylen < WLAN_KEY_LEN_GCMP_256);
>    2150		BUILD_BUG_ON(conf->keylen < WLAN_KEY_LEN_TKIP);
>    2151		BUILD_BUG_ON(conf->keylen < sizeof(status->gtk[0].key));
>    2152	
>    2153		switch (gtk_cipher) {
>    2154		case WLAN_CIPHER_SUITE_CCMP:
>    2155		case WLAN_CIPHER_SUITE_GCMP:
>    2156			conf->keylen = WLAN_KEY_LEN_CCMP;
>    2157			break;
>    2158		case WLAN_CIPHER_SUITE_GCMP_256:
>    2159			conf->keylen = WLAN_KEY_LEN_GCMP_256;
>    2160			break;
>    2161		case WLAN_CIPHER_SUITE_TKIP:
>    2162			conf->keylen = WLAN_KEY_LEN_TKIP;
>    2163			break;
>    2164		default:
>    2165			WARN_ON(1);
>    2166		}
>    2167	
>    2168		for (i = 0; i < ARRAY_SIZE(status->gtk); i++) {
>    2169			if (!status->gtk[i].len)
>    2170				continue;
>    2171	
>    2172			conf->keyidx = status->gtk[i].id;
>    2173			IWL_DEBUG_WOWLAN(mvm,
>    2174					 "Received from FW GTK cipher %d, key index %d\n",
>    2175					 conf->cipher, conf->keyidx);
>    2176			memcpy(conf->key, status->gtk[i].key,
>    2177			       sizeof(status->gtk[i].key));
>    2178	
>    2179			key = ieee80211_gtk_rekey_add(vif, conf, link_id);
>    2180			if (IS_ERR(key))
>    2181				return false;
>    2182	
>    2183			for (j = 0; j < ARRAY_SIZE(status->gtk_seq); j++) {
>    2184				if (!status->gtk_seq[j].valid ||
>    2185				    status->gtk_seq[j].key_id != key->keyidx)
>    2186					continue;
>    2187				iwl_mvm_set_key_rx_seq_idx(key, status, j);
>    2188				break;
>    2189			}
>    2190			WARN_ON(j == ARRAY_SIZE(status->gtk_seq));
>    2191		}
>    2192	
>    2193		return true;
>    2194	}
>    2195	
>