[PATCH v2] staging: rtl8192u: reduce stack frame size in ieee80211_rx_mgt_rsl

From: Arnd Bergmann
Date: Mon Jul 10 2017 - 10:06:20 EST


I ran into a stack frame size warning in code that hasn't changed much
recently, no idea why I didn't spot this earlier despite build many
thousand randconfigs.

drivers/staging/rtl8192u/ieee80211/ieee80211_rx.c: In function 'ieee80211_rx_mgt_rsl':
drivers/staging/rtl8192u/ieee80211/ieee80211_rx.c:2563:1: error: the frame size of 1676 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]

We have a couple of other copies of the same function in the kernel,
and they simply don't put a gigantic structure on the stack, so I'm
changing this copy to do the same as the others, replacing the
stack variable with a GFP_ATOMIC allocation.

Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
This one is not important, as it only seems to show up in rare
configurations. I'd suggest adding it to staging-next for 4.14
after the merge window.

v2: fix missing kfree() as pointed out by Dan Carpenter.
---
drivers/staging/rtl8192u/ieee80211/ieee80211_rx.c | 78 ++++++++++++-----------
1 file changed, 42 insertions(+), 36 deletions(-)

diff --git a/drivers/staging/rtl8192u/ieee80211/ieee80211_rx.c b/drivers/staging/rtl8192u/ieee80211/ieee80211_rx.c
index 780059c3eb60..7c8f28d7a07f 100644
--- a/drivers/staging/rtl8192u/ieee80211/ieee80211_rx.c
+++ b/drivers/staging/rtl8192u/ieee80211/ieee80211_rx.c
@@ -2329,7 +2329,7 @@ static inline void ieee80211_process_probe_response(
struct ieee80211_probe_response *beacon,
struct ieee80211_rx_stats *stats)
{
- struct ieee80211_network network;
+ struct ieee80211_network *network;
struct ieee80211_network *target;
struct ieee80211_network *oldest = NULL;
#ifdef CONFIG_IEEE80211_DEBUG
@@ -2341,7 +2341,10 @@ static inline void ieee80211_process_probe_response(
u16 capability;
//u8 wmm_info;

- memset(&network, 0, sizeof(struct ieee80211_network));
+ network = kzalloc(sizeof(*network), GFP_ATOMIC);
+ if (!network)
+ goto out;
+
capability = le16_to_cpu(beacon->capability);
IEEE80211_DEBUG_SCAN(
"'%s' (%pM): %c%c%c%c %c%c%c%c-%c%c%c%c %c%c%c%c\n",
@@ -2364,14 +2367,14 @@ static inline void ieee80211_process_probe_response(
(capability & (1 << 0x1)) ? '1' : '0',
(capability & (1 << 0x0)) ? '1' : '0');

- if (ieee80211_network_init(ieee, beacon, &network, stats)) {
+ if (ieee80211_network_init(ieee, beacon, network, stats)) {
IEEE80211_DEBUG_SCAN("Dropped '%s' (%pM) via %s.\n",
escape_essid(info_element->data,
info_element->len),
beacon->header.addr3,
fc == IEEE80211_STYPE_PROBE_RESP ?
"PROBE RESPONSE" : "BEACON");
- return;
+ goto out;
}

// For Asus EeePc request,
@@ -2381,8 +2384,8 @@ static inline void ieee80211_process_probe_response(
// then wireless adapter should do active scan from ch1~11 and
// passive scan from ch12~14

- if (!IsLegalChannel(ieee, network.channel))
- return;
+ if (!IsLegalChannel(ieee, network->channel))
+ goto out;
if (ieee->bGlobalDomain)
{
if (fc == IEEE80211_STYPE_PROBE_RESP)
@@ -2390,19 +2393,19 @@ static inline void ieee80211_process_probe_response(
// Case 1: Country code
if(IS_COUNTRY_IE_VALID(ieee) )
{
- if (!IsLegalChannel(ieee, network.channel)) {
- printk("GetScanInfo(): For Country code, filter probe response at channel(%d).\n", network.channel);
- return;
+ if (!IsLegalChannel(ieee, network->channel)) {
+ printk("GetScanInfo(): For Country code, filter probe response at channel(%d).\n", network->channel);
+ goto out;
}
}
// Case 2: No any country code.
else
{
// Filter over channel ch12~14
- if (network.channel > 11)
+ if (network->channel > 11)
{
- printk("GetScanInfo(): For Global Domain, filter probe response at channel(%d).\n", network.channel);
- return;
+ printk("GetScanInfo(): For Global Domain, filter probe response at channel(%d).\n", network->channel);
+ goto out;
}
}
}
@@ -2411,19 +2414,19 @@ static inline void ieee80211_process_probe_response(
// Case 1: Country code
if(IS_COUNTRY_IE_VALID(ieee) )
{
- if (!IsLegalChannel(ieee, network.channel)) {
- printk("GetScanInfo(): For Country code, filter beacon at channel(%d).\n",network.channel);
- return;
+ if (!IsLegalChannel(ieee, network->channel)) {
+ printk("GetScanInfo(): For Country code, filter beacon at channel(%d).\n",network->channel);
+ goto out;
}
}
// Case 2: No any country code.
else
{
// Filter over channel ch12~14
- if (network.channel > 14)
+ if (network->channel > 14)
{
- printk("GetScanInfo(): For Global Domain, filter beacon at channel(%d).\n",network.channel);
- return;
+ printk("GetScanInfo(): For Global Domain, filter beacon at channel(%d).\n",network->channel);
+ goto out;
}
}
}
@@ -2441,8 +2444,8 @@ static inline void ieee80211_process_probe_response(

spin_lock_irqsave(&ieee->lock, flags);

- if (is_same_network(&ieee->current_network, &network, ieee)) {
- update_network(&ieee->current_network, &network);
+ if (is_same_network(&ieee->current_network, network, ieee)) {
+ update_network(&ieee->current_network, network);
if ((ieee->current_network.mode == IEEE_N_24G || ieee->current_network.mode == IEEE_G)
&& ieee->current_network.berp_info_valid){
if(ieee->current_network.erp_value& ERP_UseProtection)
@@ -2456,11 +2459,11 @@ static inline void ieee80211_process_probe_response(
ieee->LinkDetectInfo.NumRecvBcnInPeriod++;
}
else //hidden AP
- network.flags = (~NETWORK_EMPTY_ESSID & network.flags)|(NETWORK_EMPTY_ESSID & ieee->current_network.flags);
+ network->flags = (~NETWORK_EMPTY_ESSID & network->flags)|(NETWORK_EMPTY_ESSID & ieee->current_network.flags);
}

list_for_each_entry(target, &ieee->network_list, list) {
- if (is_same_network(target, &network, ieee))
+ if (is_same_network(target, network, ieee))
break;
if ((oldest == NULL) ||
(target->last_scanned < oldest->last_scanned))
@@ -2489,16 +2492,16 @@ static inline void ieee80211_process_probe_response(

#ifdef CONFIG_IEEE80211_DEBUG
IEEE80211_DEBUG_SCAN("Adding '%s' (%pM) via %s.\n",
- escape_essid(network.ssid,
- network.ssid_len),
- network.bssid,
+ escape_essid(network->ssid,
+ network->ssid_len),
+ network->bssid,
fc == IEEE80211_STYPE_PROBE_RESP ?
"PROBE RESPONSE" : "BEACON");
#endif
- memcpy(target, &network, sizeof(*target));
+ memcpy(target, network, sizeof(*target));
list_add_tail(&target->list, &ieee->network_list);
if(ieee->softmac_features & IEEE_SOFTMAC_ASSOCIATE)
- ieee80211_softmac_new_net(ieee,&network);
+ ieee80211_softmac_new_net(ieee,network);
} else {
IEEE80211_DEBUG_SCAN("Updating '%s' (%pM) via %s.\n",
escape_essid(target->ssid,
@@ -2514,27 +2517,30 @@ static inline void ieee80211_process_probe_response(
renew = !time_after(target->last_scanned + ieee->scan_age, jiffies);
//YJ,add,080819,for hidden ap
if(is_beacon(beacon->header.frame_ctl) == 0)
- network.flags = (~NETWORK_EMPTY_ESSID & network.flags)|(NETWORK_EMPTY_ESSID & target->flags);
- //if(strncmp(network.ssid, "linksys-c",9) == 0)
- // printk("====>2 network.ssid=%s FLAG=%d target.ssid=%s FLAG=%d\n", network.ssid, network.flags, target->ssid, target->flags);
- if(((network.flags & NETWORK_EMPTY_ESSID) == NETWORK_EMPTY_ESSID) \
- && (((network.ssid_len > 0) && (strncmp(target->ssid, network.ssid, network.ssid_len)))\
- ||((ieee->current_network.ssid_len == network.ssid_len)&&(strncmp(ieee->current_network.ssid, network.ssid, network.ssid_len) == 0)&&(ieee->state == IEEE80211_NOLINK))))
+ network->flags = (~NETWORK_EMPTY_ESSID & network->flags)|(NETWORK_EMPTY_ESSID & target->flags);
+ //if(strncmp(network->ssid, "linksys-c",9) == 0)
+ // printk("====>2 network->ssid=%s FLAG=%d target.ssid=%s FLAG=%d\n", network->ssid, network->flags, target->ssid, target->flags);
+ if(((network->flags & NETWORK_EMPTY_ESSID) == NETWORK_EMPTY_ESSID) \
+ && (((network->ssid_len > 0) && (strncmp(target->ssid, network->ssid, network->ssid_len)))\
+ ||((ieee->current_network.ssid_len == network->ssid_len)&&(strncmp(ieee->current_network.ssid, network->ssid, network->ssid_len) == 0)&&(ieee->state == IEEE80211_NOLINK))))
renew = 1;
//YJ,add,080819,for hidden ap,end

- update_network(target, &network);
+ update_network(target, network);
if(renew && (ieee->softmac_features & IEEE_SOFTMAC_ASSOCIATE))
- ieee80211_softmac_new_net(ieee,&network);
+ ieee80211_softmac_new_net(ieee,network);
}

spin_unlock_irqrestore(&ieee->lock, flags);
- if (is_beacon(beacon->header.frame_ctl)&&is_same_network(&ieee->current_network, &network, ieee)&&\
+ if (is_beacon(beacon->header.frame_ctl)&&is_same_network(&ieee->current_network, network, ieee)&&\
(ieee->state == IEEE80211_LINKED)) {
if (ieee->handle_beacon != NULL) {
ieee->handle_beacon(ieee->dev,beacon,&ieee->current_network);
}
}
+
+out:
+ kfree(network);
}

void ieee80211_rx_mgt(struct ieee80211_device *ieee,
--
2.9.0