From 00d7ea11ff0783e24fe70778f3141270b561aaa1 Mon Sep 17 00:00:00 2001 From: Amitkumar Karwar Date: Fri, 15 Mar 2013 18:47:05 -0700 Subject: mwifiex: fix race when queuing commands 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. Cc: # 3.8 Reported-by: Daniel Drake Tested-by: Daniel Drake Tested-by: Marco Cesarano Signed-off-by: Amitkumar Karwar Signed-off-by: Bing Zhao Signed-off-by: John W. Linville --- drivers/net/wireless/mwifiex/scan.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'drivers/net/wireless/mwifiex/scan.c') diff --git a/drivers/net/wireless/mwifiex/scan.c b/drivers/net/wireless/mwifiex/scan.c index bb60c2754a9..d215b4d3c51 100644 --- a/drivers/net/wireless/mwifiex/scan.c +++ b/drivers/net/wireless/mwifiex/scan.c @@ -1388,10 +1388,13 @@ int mwifiex_scan_networks(struct mwifiex_private *priv, 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); @@ -1946,9 +1949,6 @@ int mwifiex_request_scan(struct mwifiex_private *priv, /* Normal scan */ ret = mwifiex_scan_networks(priv, NULL); - if (!ret) - ret = mwifiex_wait_queue_complete(priv->adapter); - up(&priv->async_sem); return ret; -- cgit v1.2.3-70-g09d2