Attachment 212751 Details for Bug 314631 – Proposed patch to fix the deadlock

[patch] Proposed patch to fix the deadlock

linux-2.6.9-55-consolespin_fix_to_RH.patch (text/plain), 1.38 KB, created by Flavio Leitner on 2007-10-01 19:43:51 UTC

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Creator: Flavio Leitner

Created: 2007-10-01 19:43:51 UTC

Size: 1.38 KB

patch

obsolete

>--- ./net/core/netpoll.c.orig	2007-09-26 19:43:30.000000000 -0700
>+++ ./net/core/netpoll.c	2007-09-26 20:13:24.000000000 -0700
>@@ -232,7 +232,7 @@
> 	skb_reserve(skb, reserve);
> 	return skb;
> }
>-
>+#define MAX_NETCONSOLE_SPINLOCK_RETRIES 20000
> /*
>  *  This function can be called from virtual device drivers, such as the
>  *  bonding driver.  In this case, skb->dev is filled in with the real
>@@ -247,6 +248,8 @@
> 	struct net_device_wrapper *ndw = dev_wrapper(dev);
> 	struct netpoll_info *npinfo;
> 
>+        int spinlock_retry_count, got_lock;
>+
> 	if(!ndw || !np || !dev || !netif_running(dev)) {
> 		__kfree_skb(skb);
> 		return;
>@@ -262,7 +265,20 @@
> 
> 	do {
> 		npinfo->tries--;
>-		spin_lock(&dev->xmit_lock);
>+                /* pradeep.vincent@gmail.com - Use trylock to prevent deadlock 
>+                         due to interrupt context lock attempt during main 
>+                         network tx code path */ 
>+                spinlock_retry_count = 0;
>+                do {
>+                    got_lock = spin_trylock(&dev->xmit_lock);
>+                    if (unlikely(!got_lock))
>+                       udelay(1);
>+                } while ( !got_lock && ++spinlock_retry_count < MAX_NETCONSOLE_SPINLOCK_RETRIES);
>+                if (unlikely(!got_lock) ) {
>+                    __kfree_skb(skb);
>+                    return;
>+                } 
>+
> 		dev->xmit_lock_owner = smp_processor_id();
> 
> 		/*

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Attachments on bug 314631: 212751