3.8-stable review patch. If anyone has any objections, please let me know.
------------------ From: Amitkumar Karwar <[email protected]> commit 00d7ea11ff0783e24fe70778f3141270b561aaa1 upstream. Running the following script repeatedly on XO-4 with SD8787 produces command timeout and system lockup. insmod mwifiex_sdio.ko sleep 1 ifconfig eth0 up iwlist eth0 scan & sleep 0.5 rmmod mwifiex_sdio mwifiex_send_cmd_async() is called for sync as well as async commands. (mwifiex_send_cmd_sync() internally calls it for sync command.) "adapter->cmd_queued" gets filled inside mwifiex_send_cmd_async() routine for both types of commands. But it is used only for sync commands in mwifiex_wait_queue_complete(). This could lead to a race when two threads try to queue a sync command with another sync/async command simultaneously. Get rid of global variable and pass command node as a parameter to mwifiex_wait_queue_complete() to fix the problem. Reported-by: Daniel Drake <[email protected]> Tested-by: Daniel Drake <[email protected]> Tested-by: Marco Cesarano <[email protected]> Signed-off-by: Amitkumar Karwar <[email protected]> Signed-off-by: Bing Zhao <[email protected]> Signed-off-by: John W. Linville <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/net/wireless/mwifiex/cmdevt.c | 5 ++--- drivers/net/wireless/mwifiex/main.h | 4 ++-- drivers/net/wireless/mwifiex/scan.c | 8 ++++---- drivers/net/wireless/mwifiex/sta_ioctl.c | 10 ++-------- 4 files changed, 10 insertions(+), 17 deletions(-) --- a/drivers/net/wireless/mwifiex/cmdevt.c +++ b/drivers/net/wireless/mwifiex/cmdevt.c @@ -488,8 +488,6 @@ int mwifiex_send_cmd_sync(struct mwifiex ret = mwifiex_send_cmd_async(priv, cmd_no, cmd_action, cmd_oid, data_buf); - if (!ret) - ret = mwifiex_wait_queue_complete(adapter); return ret; } @@ -592,9 +590,10 @@ int mwifiex_send_cmd_async(struct mwifie if (cmd_no == HostCmd_CMD_802_11_SCAN) { mwifiex_queue_scan_cmd(priv, cmd_node); } else { - adapter->cmd_queued = cmd_node; mwifiex_insert_cmd_to_pending_q(adapter, cmd_node, true); queue_work(adapter->workqueue, &adapter->main_work); + if (cmd_node->wait_q_enabled) + ret = mwifiex_wait_queue_complete(adapter, cmd_node); } return ret; --- a/drivers/net/wireless/mwifiex/main.h +++ b/drivers/net/wireless/mwifiex/main.h @@ -714,7 +714,6 @@ struct mwifiex_adapter { u16 cmd_wait_q_required; struct mwifiex_wait_queue cmd_wait_q; u8 scan_wait_q_woken; - struct cmd_ctrl_node *cmd_queued; spinlock_t queue_lock; /* lock for tx queues */ struct completion fw_load; u8 country_code[IEEE80211_COUNTRY_STRING_LEN]; @@ -994,7 +993,8 @@ int mwifiex_request_set_multicast_list(s struct mwifiex_multicast_list *mcast_list); int mwifiex_copy_mcast_addr(struct mwifiex_multicast_list *mlist, struct net_device *dev); -int mwifiex_wait_queue_complete(struct mwifiex_adapter *adapter); +int mwifiex_wait_queue_complete(struct mwifiex_adapter *adapter, + struct cmd_ctrl_node *cmd_queued); int mwifiex_bss_start(struct mwifiex_private *priv, struct cfg80211_bss *bss, struct cfg80211_ssid *req_ssid); int mwifiex_cancel_hs(struct mwifiex_private *priv, int cmd_type); --- a/drivers/net/wireless/mwifiex/scan.c +++ b/drivers/net/wireless/mwifiex/scan.c @@ -1366,10 +1366,13 @@ int mwifiex_scan_networks(struct mwifiex list_del(&cmd_node->list); spin_unlock_irqrestore(&adapter->scan_pending_q_lock, flags); - adapter->cmd_queued = cmd_node; mwifiex_insert_cmd_to_pending_q(adapter, cmd_node, true); queue_work(adapter->workqueue, &adapter->main_work); + + /* Perform internal scan synchronously */ + if (!priv->scan_request) + mwifiex_wait_queue_complete(adapter, cmd_node); } else { spin_unlock_irqrestore(&adapter->scan_pending_q_lock, flags); @@ -1923,9 +1926,6 @@ int mwifiex_request_scan(struct mwifiex_ /* Normal scan */ ret = mwifiex_scan_networks(priv, NULL); - if (!ret) - ret = mwifiex_wait_queue_complete(priv->adapter); - up(&priv->async_sem); return ret; --- a/drivers/net/wireless/mwifiex/sta_ioctl.c +++ b/drivers/net/wireless/mwifiex/sta_ioctl.c @@ -54,16 +54,10 @@ int mwifiex_copy_mcast_addr(struct mwifi * This function waits on a cmd wait queue. It also cancels the pending * request after waking up, in case of errors. */ -int mwifiex_wait_queue_complete(struct mwifiex_adapter *adapter) +int mwifiex_wait_queue_complete(struct mwifiex_adapter *adapter, + struct cmd_ctrl_node *cmd_queued) { int status; - struct cmd_ctrl_node *cmd_queued; - - if (!adapter->cmd_queued) - return 0; - - cmd_queued = adapter->cmd_queued; - adapter->cmd_queued = NULL; dev_dbg(adapter->dev, "cmd pending\n"); atomic_inc(&adapter->cmd_pending); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
