Search Linux Wireless

[PATCH] net/wireless: ipw2200: Fix race condition in the command completion acknowledge

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Driver incorrectly validates command completion: instead of waiting
for a command to be acknowledged it continues execution.  Most of the
time driver gets acknowledge of the command completion in a tasklet
before it executes the next one. But sometimes it sends the next
command before it gets acknowledge for the previous one. In such a
case one of the following error messages appear in the log:

Failed to send SYSTEM_CONFIG: Already sending a command.
Failed to send ASSOCIATE: Already sending a command.
Failed to send TX_POWER: Already sending a command.

After that you need to reload the driver to get it working again.

This bug occurs during roammaping (reported by Sam Varshavchik)
and machine booting (reported by Tom Gundersen and Mads Kiilerich)

This patch doesn't fix the delay issue during firmware load.
But at least device now works as usual after boot.

Cc: stable@xxxxxxxxxx
Signed-off-by: Stanislav Yakovlev <stas.yakovlev@xxxxxxxxx>
 drivers/net/wireless/ipw2x00/ipw2200.c |   13 ++++++++++++-
 1 files changed, 12 insertions(+), 1 deletions(-)

diff --git a/drivers/net/wireless/ipw2x00/ipw2200.c b/drivers/net/wireless/ipw2x00/ipw2200.c
index 4130802..8cbafa5 100644
--- a/drivers/net/wireless/ipw2x00/ipw2200.c
+++ b/drivers/net/wireless/ipw2x00/ipw2200.c
@@ -2192,6 +2192,7 @@ static int __ipw_send_cmd(struct ipw_priv *priv, struct host_cmd *cmd)
 	int rc = 0;
 	unsigned long flags;
+	unsigned long now, end;
 	spin_lock_irqsave(&priv->lock, flags);
 	if (priv->status & STATUS_HCMD_ACTIVE) {
@@ -2233,10 +2234,20 @@ static int __ipw_send_cmd(struct ipw_priv *priv, struct host_cmd *cmd)
 	spin_unlock_irqrestore(&priv->lock, flags);
+	now = jiffies;
 	rc = wait_event_interruptible_timeout(priv->wait_command_queue,
 						status & STATUS_HCMD_ACTIVE),
+					      end - now);
+	if (rc < 0) {
+		now = jiffies;
+		if (time_before(now, end))
+			goto again;
+		rc = 0;
+	}
 	if (rc == 0) {
 		spin_lock_irqsave(&priv->lock, flags);
 		if (priv->status & STATUS_HCMD_ACTIVE) {

To unsubscribe from this list: send the line "unsubscribe linux-wireless" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at

[Linux Kernel]     [Linux Bluetooth]     [Linux Netdev]     [Kernel Newbies]     [Share Photos]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Photo]     [Yosemite]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Samba]     [Video 4 Linux]     [Device Mapper]     [Linux Resources]     [Free Dating]     [M2M Wireless]

Add to Google Powered by Linux