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libertas: ensure we clean up a scan request properly 

Commit 2e30168b ("libertas: terminate scan when stopping interface")
adds cleanup code to lbs_eth_stop to call cfg80211_scan_done if there's
an outstanding cfg80211_scan_request.  However, it assumes that the
scan request was allocated via the cfg80211 stack.  Libertas has
its own internal allocation method, kept track of with
priv->internal_scan.  This doesn't set scan_req->wiphy, amongst other
things, which results in hitting a BUG() when we call cfg80211_scan_done
on the request.

This provides a function to take care of the low-level scan_req cleanup
details.  We simply call that to deal with finishing up scan requests.

The bug we were hitting was:

[  964.321495] kernel BUG at net/wireless/core.h:87!
[  964.329970] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[  964.341963] pgd = dcf80000
...
[  964.849998] 9fe0: 00000000 beb417b8 4018e280 401e822c 60000010 00000004 00000000 00000000
[  964.865007] [<c003104c>] (__bug+0x1c/0x28) from [<c0384ffc>] (cfg80211_scan_done+0x54/0x6c)
[  964.895324] [<c0384ffc>] (cfg80211_scan_done+0x54/0x6c) from [<bf028bac>] (lbs_eth_stop+0x10c/0x188 [libertas])
[  964.895324] [<bf028bac>] (lbs_eth_stop+0x10c/0x188 [libertas]) from [<c03002a0>] (__dev_close_many+0x94/0xc4)
[  964.918995] [<c03002a0>] (__dev_close_many+0x94/0xc4) from [<c030037c>] (dev_close_many+0x78/0xe0)

Signed-off-by: Andres Salomon <dilinger@queued.net>
Acked-by: Dan Williams <dcbw@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Andres Salomon 2011-10-26 10:19:26 -07:00 committed by John W. Linville
parent 93348928f2
commit 3209e061ad
3 changed files with 20 additions and 12 deletions
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25
drivers/net/wireless/libertas/cfg.c
View File

@ -728,15 +728,9 @@ static void lbs_scan_worker(struct work_struct *work)
le16_to_cpu(scan_cmd->hdr.size),
lbs_ret_scan, 0);
if (priv->scan_channel >= priv->scan_req->n_channels) {
if (priv->scan_channel >= priv->scan_req->n_channels)
/* Mark scan done */
if (priv->internal_scan)
kfree(priv->scan_req);
else
cfg80211_scan_done(priv->scan_req, false);
priv->scan_req = NULL;
}
lbs_scan_done(priv);
/* Restart network */
if (carrier)
@ -774,6 +768,21 @@ static void _internal_start_scan(struct lbs_private *priv, bool internal,
lbs_deb_leave(LBS_DEB_CFG80211);
}
/*
* Clean up priv->scan_req. Should be used to handle the allocation details.
*/
void lbs_scan_done(struct lbs_private *priv)
{
WARN_ON(!priv->scan_req);
if (priv->internal_scan)
kfree(priv->scan_req);
else
cfg80211_scan_done(priv->scan_req, false);
priv->scan_req = NULL;
}
static int lbs_cfg_scan(struct wiphy *wiphy,
struct net_device *dev,
struct cfg80211_scan_request *request)

1
drivers/net/wireless/libertas/cfg.h
View File

@ -16,6 +16,7 @@ int lbs_reg_notifier(struct wiphy *wiphy,
void lbs_send_disconnect_notification(struct lbs_private *priv);
void lbs_send_mic_failureevent(struct lbs_private *priv, u32 event);
void lbs_scan_done(struct lbs_private *priv);
void lbs_scan_deinit(struct lbs_private *priv);
int lbs_disconnect(struct lbs_private *priv, u16 reason);

6
drivers/net/wireless/libertas/main.c
View File

@ -255,10 +255,8 @@ static int lbs_eth_stop(struct net_device *dev)
lbs_update_mcast(priv);
cancel_delayed_work_sync(&priv->scan_work);
if (priv->scan_req) {
cfg80211_scan_done(priv->scan_req, false);
priv->scan_req = NULL;
}
if (priv->scan_req)
lbs_scan_done(priv);
netif_carrier_off(priv->dev);