2011-03-29 13:44:28

by Juuso Oikarinen

Subject: [PATCH] wl12xx: Handle duplicate calling of remove interface

From: Juuso Oikarinen <[email protected]>

Because of the hardware recovery mechanism, its possible the
__wl1271_op_remove_interface is called twice. Currently, this leads to a
kernel crash even before a kernel WARNing can be issued.

Fix this.

Signed-off-by: Juuso Oikarinen <[email protected]>
---
drivers/net/wireless/wl12xx/main.c | 29 ++++++++++++++++++++++++++---
drivers/net/wireless/wl12xx/wl12xx.h | 3 ++-
2 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/wl12xx/main.c b/drivers/net/wireless/wl12xx/main.c
index 85cb4da..b2bd353 100644
--- a/drivers/net/wireless/wl12xx/main.c
+++ b/drivers/net/wireless/wl12xx/main.c
@@ -1304,6 +1304,16 @@ static int wl1271_op_add_interface(struct ieee80211_hw *hw,
goto out;
}

+ /*
+ * in some very corner case HW recovery scenarios its possible to
+ * get here before __wl1271_op_remove_interface is complete, so
+ * opt out if that is the case.
+ */
+ if (test_bit(WL1271_FLAG_IF_INITIALIZED, &wl->flags)) {
+ ret = -EBUSY;
+ goto out;
+ }
+
switch (vif->type) {
case NL80211_IFTYPE_STATION:
wl->bss_type = BSS_TYPE_STA_BSS;
@@ -1372,6 +1382,7 @@ power_off:

wl->vif = vif;
wl->state = WL1271_STATE_ON;
+ set_bit(WL1271_FLAG_IF_INITIALIZED, &wl->flags);
wl1271_info("firmware booted (%s)", wl->chip.fw_ver_str);

/* update hw/fw version info in wiphy struct */
@@ -1409,14 +1420,16 @@ static void __wl1271_op_remove_interface(struct wl1271 *wl)

wl1271_debug(DEBUG_MAC80211, "mac80211 remove interface");

+ /* because of hardware recovery, we may get here twice */
+ if (wl->state != WL1271_STATE_ON)
+ return;
+
wl1271_info("down");

mutex_lock(&wl_list_mutex);
list_del(&wl->list);
mutex_unlock(&wl_list_mutex);

- WARN_ON(wl->state != WL1271_STATE_ON);
-
/* enable dyn ps just in case (if left on due to fw crash etc) */
if (wl->bss_type == BSS_TYPE_STA_BSS)
ieee80211_enable_dyn_ps(wl->vif);
@@ -1429,6 +1442,10 @@ static void __wl1271_op_remove_interface(struct wl1271 *wl)
ieee80211_scan_completed(wl->hw, true);
}

+ /*
+ * this must be before the cancel_work calls below, so that the work
+ * functions don't perform further work.
+ */
wl->state = WL1271_STATE_OFF;

mutex_unlock(&wl->mutex);
@@ -1465,7 +1482,6 @@ static void __wl1271_op_remove_interface(struct wl1271 *wl)
wl->time_offset = 0;
wl->session_counter = 0;
wl->rate_set = CONF_TX_RATE_MASK_BASIC;
- wl->flags = 0;
wl->vif = NULL;
wl->filters = 0;
wl1271_free_ap_keys(wl);
@@ -1474,6 +1490,13 @@ static void __wl1271_op_remove_interface(struct wl1271 *wl)
wl->ap_ps_map = 0;
wl->block_size = 0;

+ /*
+ * this is performed after the cancel_work calls and the associated
+ * mutex_lock, so that wl1271_op_add_interface does not accidentally
+ * get executed before all these vars have been reset.
+ */
+ wl->flags = 0;
+
for (i = 0; i < NUM_TX_QUEUES; i++)
wl->tx_blocks_freed[i] = 0;

diff --git a/drivers/net/wireless/wl12xx/wl12xx.h b/drivers/net/wireless/wl12xx/wl12xx.h
index b04481a..a38b130 100644
--- a/drivers/net/wireless/wl12xx/wl12xx.h
+++ b/drivers/net/wireless/wl12xx/wl12xx.h
@@ -353,7 +353,8 @@ enum wl12xx_flags {
WL1271_FLAG_PSPOLL_FAILURE,
WL1271_FLAG_STA_STATE_SENT,
WL1271_FLAG_FW_TX_BUSY,
- WL1271_FLAG_AP_STARTED
+ WL1271_FLAG_AP_STARTED,
+ WL1271_FLAG_IF_INITIALIZED,
};

struct wl1271_link {
--
1.7.1

2011-04-01 09:03:31

by Luciano Coelho

Subject: Re: [PATCH] wl12xx: Handle duplicate calling of remove interface

On Tue, 2011-03-29 at 16:43 +0300, [email protected] wrote:
> From: Juuso Oikarinen <[email protected]>
>
> Because of the hardware recovery mechanism, its possible the
> __wl1271_op_remove_interface is called twice. Currently, this leads to a
> kernel crash even before a kernel WARNing can be issued.
>
> Fix this.
>
> Signed-off-by: Juuso Oikarinen <[email protected]>
> ---

Applied, thanks Juuso!

--
Cheers,
Luca.