Attachment 65811 Details for Bug 146880

[patch] This is the patch I submitted to mainline

ipw2200-lockup-fix (text/plain), 2.05 KB, created by Olaf Kirch on 2006-01-31 09:11:00 UTC

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Creator: Olaf Kirch

Created: 2006-01-31 09:11:00 UTC

Size: 2.05 KB

patch

obsolete

>From: Olaf Kirch <okir@suse.de>
>Subject: ipw2200 - release semaphore when sleeping in ipw_request_direct_scan
>References: 133513, 146880
>
>  When ipw_request_direct_scan finds there is a scan in progress, it
>  will go to sleep until the other scan is complete.
>
>  This causes frequent deadlocks: wpa_supplicant triggers the scan, and
>  blocks. Note that this will first take the rtnl_lock (this is an
>  ioctl), and then the ipw2200 interface's priv->sem.
>  
>  The ipw2200 worker thread also tries to do something and blocks on
>  priv->sem.
>
>  events/0 is trying run the linkwatch_queue (net/core/link_watch.c),
>  and tries to take the rtnl lock but blocks as well. While it does that,
>  it holds the lock_cpu_hotplug() lock for its CPU, effectively blocking
>  all sorts of other tasks that try to perform a flush_workqueue on some
>  work queue.
>
>  For some odd reason, the SCAN_COMPLETED notification never arrives,
>  possibly because the device loses the beacon and disassociates. So
>  things remain stuck.
>
>  For sysrq-t ouput and other details, see
>  https://bugzilla.novell.com/show_bug.cgi?id=133513
>
>Signed-off-by: Olaf Kirch <okir@suse.de>
>
> drivers/net/wireless/ipw2200.c |   14 ++++++--------
> 1 files changed, 6 insertions(+), 8 deletions(-)
>
>Index: linux-2.6.15/drivers/net/wireless/ipw2200.c
>===================================================================
>--- linux-2.6.15.orig/drivers/net/wireless/ipw2200.c
>+++ linux-2.6.15/drivers/net/wireless/ipw2200.c
>@@ -8940,14 +8940,12 @@ static int ipw_request_direct_scan(struc
> 	IPW_DEBUG_HC("starting request direct scan!\n");
> 
> 	if (priv->status & (STATUS_SCANNING | STATUS_SCAN_ABORTING)) {
>-		err = wait_event_interruptible(priv->wait_state,
>-					       !(priv->
>-						 status & (STATUS_SCANNING |
>-							   STATUS_SCAN_ABORTING)));
>-		if (err) {
>-			IPW_DEBUG_HC("aborting direct scan");
>-			goto done;
>-		}
>+		/* We should not sleep here; otherwise we will block most
>+		 * of the system (for instance, we hold rtnl_lock when we
>+		 * get here).
>+		 */
>+		err = -EAGAIN;
>+		goto done;
> 	}
> 	memset(&scan, 0, sizeof(scan));
>

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Attachments on bug 146880: 65811 | 66038 | 66040