2011-02-12 21:25:26

by Arik Nemtsov

Subject: [PATCH] wl12xx: avoid blocking while holding rcu lock on bss info change

Some blocking functions were called while holding the rcu lock for
accessing STA information. This can lead to a deadlock.

Save the required info beforehand and release the rcu without
blocking.

Signed-off-by: Arik Nemtsov <[email protected]>
---
drivers/net/wireless/wl12xx/main.c | 15 +++++++++------
1 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/net/wireless/wl12xx/main.c b/drivers/net/wireless/wl12xx/main.c
index 61dea73..40b1bf1 100644
--- a/drivers/net/wireless/wl12xx/main.c
+++ b/drivers/net/wireless/wl12xx/main.c
@@ -2218,6 +2218,8 @@ static void wl1271_bss_info_changed_sta(struct wl1271 *wl,
u32 sta_rate_set = 0;
int ret;
struct ieee80211_sta *sta;
+ bool sta_exists = false;
+ struct ieee80211_sta_ht_cap sta_ht_cap;

if (is_ibss) {
ret = wl1271_bss_beacon_info_changed(wl, vif, bss_conf,
@@ -2289,16 +2291,20 @@ static void wl1271_bss_info_changed_sta(struct wl1271 *wl,
if (sta->ht_cap.ht_supported)
sta_rate_set |=
(sta->ht_cap.mcs.rx_mask[0] << HW_HT_RATES_OFFSET);
+ sta_ht_cap = sta->ht_cap;
+ sta_exists = true;
+ }
+ rcu_read_unlock();

+ if (sta_exists) {
/* handle new association with HT and HT information change */
if ((changed & BSS_CHANGED_HT) &&
(bss_conf->channel_type != NL80211_CHAN_NO_HT)) {
- ret = wl1271_acx_set_ht_capabilities(wl, &sta->ht_cap,
+ ret = wl1271_acx_set_ht_capabilities(wl, &sta_ht_cap,
true);
if (ret < 0) {
wl1271_warning("Set ht cap true failed %d",
ret);
- rcu_read_unlock();
goto out;
}
ret = wl1271_acx_set_ht_information(wl,
@@ -2306,23 +2312,20 @@ static void wl1271_bss_info_changed_sta(struct wl1271 *wl,
if (ret < 0) {
wl1271_warning("Set ht information failed %d",
ret);
- rcu_read_unlock();
goto out;
}
}
/* handle new association without HT and disassociation */
else if (changed & BSS_CHANGED_ASSOC) {
- ret = wl1271_acx_set_ht_capabilities(wl, &sta->ht_cap,
+ ret = wl1271_acx_set_ht_capabilities(wl, &sta_ht_cap,
false);
if (ret < 0) {
wl1271_warning("Set ht cap false failed %d",
ret);
- rcu_read_unlock();
goto out;
}
}
}
- rcu_read_unlock();

if ((changed & BSS_CHANGED_ASSOC)) {
if (bss_conf->assoc) {
--
1.7.1

2011-02-23 13:53:50

by Luciano Coelho

Subject: Re: [PATCH] wl12xx: avoid blocking while holding rcu lock on bss info change

On Sat, 2011-02-12 at 23:24 +0200, Arik Nemtsov wrote:
> Some blocking functions were called while holding the rcu lock for
> accessing STA information. This can lead to a deadlock.
>
> Save the required info beforehand and release the rcu without
> blocking.
>
> Signed-off-by: Arik Nemtsov <[email protected]>
> ---

Applied, thank you!

--
Cheers,
Luca.