From: Amitkumar Karwar <akarwar@xxxxxxxxxxx>
Sometimes pending internal scan commands are delayed to give
preference to Tx traffic. 'scan_processing' flag has been
checked at the beginning of delay timer routine to know if in the
meantime scan operation has been cancelled.
There is a corner case where pending scan commands are emptied
after scan_processing flag check is passed. In this case
wrong pointer returned by list_first_entry() is passed to
list_del() which causes system hang.
This patch fixes the issue by adding list_empty() check.
Signed-off-by: Amitkumar Karwar <akarwar@xxxxxxxxxxx>
Signed-off-by: Bing Zhao <bzhao@xxxxxxxxxxx>
---
drivers/net/wireless/mwifiex/main.c | 16 +++++++++++-----
1 file changed, 11 insertions(+), 5 deletions(-)
diff --git a/drivers/net/wireless/mwifiex/main.c b/drivers/net/wireless/mwifiex/main.c
index 3e5194f..dfa37ea 100644
--- a/drivers/net/wireless/mwifiex/main.c
+++ b/drivers/net/wireless/mwifiex/main.c
@@ -33,6 +33,7 @@ static void scan_delay_timer_fn(unsigned long data)
struct mwifiex_private *priv = (struct mwifiex_private *)data;
struct mwifiex_adapter *adapter = priv->adapter;
struct cmd_ctrl_node *cmd_node, *tmp_node;
+ spinlock_t *scan_q_lock = &adapter->scan_pending_q_lock;
unsigned long flags;
if (adapter->surprise_removed)
@@ -44,13 +45,13 @@ static void scan_delay_timer_fn(unsigned long data)
* Abort scan operation by cancelling all pending scan
* commands
*/
- spin_lock_irqsave(&adapter->scan_pending_q_lock, flags);
+ spin_lock_irqsave(scan_q_lock, flags);
list_for_each_entry_safe(cmd_node, tmp_node,
&adapter->scan_pending_q, list) {
list_del(&cmd_node->list);
mwifiex_insert_cmd_to_free_q(adapter, cmd_node);
}
- spin_unlock_irqrestore(&adapter->scan_pending_q_lock, flags);
+ spin_unlock_irqrestore(scan_q_lock, flags);
spin_lock_irqsave(&adapter->mwifiex_cmd_lock, flags);
adapter->scan_processing = false;
@@ -79,12 +80,17 @@ static void scan_delay_timer_fn(unsigned long data)
*/
adapter->scan_delay_cnt = 0;
adapter->empty_tx_q_cnt = 0;
- spin_lock_irqsave(&adapter->scan_pending_q_lock, flags);
+ spin_lock_irqsave(scan_q_lock, flags);
+
+ if (list_empty(&adapter->scan_pending_q)) {
+ spin_unlock_irqrestore(scan_q_lock, flags);
+ goto done;
+ }
+
cmd_node = list_first_entry(&adapter->scan_pending_q,
struct cmd_ctrl_node, list);
list_del(&cmd_node->list);
- spin_unlock_irqrestore(&adapter->scan_pending_q_lock,
- flags);
+ spin_unlock_irqrestore(scan_q_lock, flags);
mwifiex_insert_cmd_to_pending_q(adapter, cmd_node,
true);
--
1.8.2.3
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