Attachment 194551 Details for Bug 251978 – updated patch to fix possible deadlock

[patch] updated patch to fix possible deadlock

linux-kernel-test.patch (text/plain), 2.83 KB, created by Neil Horman on 2007-09-13 11:45:44 UTC

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Creator: Neil Horman

Created: 2007-09-13 11:45:44 UTC

Size: 2.83 KB

patch

obsolete

>--- linux-2.6.9/include/linux/netdevice.h.orig	2007-09-06 09:11:54.000000000 -0400
>+++ linux-2.6.9/include/linux/netdevice.h	2007-09-06 09:36:12.000000000 -0400
>@@ -37,6 +37,7 @@
> #include <linux/config.h>
> #include <linux/device.h>
> #include <linux/percpu.h>
>+#include <linux/kernel.h>
> 
> struct divert_blk;
> struct vlan_group;
>@@ -238,7 +239,8 @@
> 	__LINK_STATE_SCHED,
> 	__LINK_STATE_NOCARRIER,
> 	__LINK_STATE_RX_SCHED,
>-	__LINK_STATE_LINKWATCH_PENDING
>+	__LINK_STATE_LINKWATCH_PENDING,
>+	__LINK_STATE_NETPOLL_SERVICED
> };
> 
> 
>@@ -886,6 +888,9 @@
> {
> 	unsigned long flags;
> 
>+	if (!crashdump_mode() &&
>+	     test_bit(__LINK_STATE_NETPOLL_SERVICED, &dev->state))
>+		return;
> 	local_irq_save(flags);
> 	BUG_ON(!test_bit(__LINK_STATE_RX_SCHED, &dev->state));
> 	list_del(&dev->poll_list);
>@@ -913,6 +918,8 @@
>  */
> static inline void __netif_rx_complete(struct net_device *dev)
> {
>+	if (test_bit(__LINK_STATE_NETPOLL_SERVICED, &dev->state))
>+		return;
> 	BUG_ON(!test_bit(__LINK_STATE_RX_SCHED, &dev->state));
> 	list_del(&dev->poll_list);
> 	smp_mb__before_clear_bit();
>--- linux-2.6.9/net/core/netpoll.c.orig	2007-09-06 09:11:36.000000000 -0400
>+++ linux-2.6.9/net/core/netpoll.c	2007-09-06 09:30:48.000000000 -0400
>@@ -94,9 +94,15 @@
> 		return;
> 	npinfo = ndw->npinfo;
> 
>-	if (test_bit(__LINK_STATE_RX_SCHED, &dev->state) &&
>-	    npinfo->poll_owner != smp_processor_id() &&
>+	if (npinfo->poll_owner != smp_processor_id() &&
> 	    spin_trylock(&npinfo->poll_lock)) {
>+		/* net_rx_action already got to us */
>+		if (!test_bit(__LINK_STATE_RX_SCHED, &dev->state))
>+			goto skip;
>+		/*
>+		 * This gets cleared in net_rx_action
>+		 */
>+		set_bit(__LINK_STATE_NETPOLL_SERVICED, &dev->state);
> 		npinfo->rx_flags |= NETPOLL_RX_DROP;
> 		atomic_inc(&trapped);
> 
>@@ -104,6 +110,7 @@
> 
> 		atomic_dec(&trapped);
> 		npinfo->rx_flags &= ~NETPOLL_RX_DROP;
>+ skip:
> 		spin_unlock(&npinfo->poll_lock);
> 	}
> }
>--- linux-2.6.9/net/core/dev.c.orig	2007-09-06 09:11:54.000000000 -0400
>+++ linux-2.6.9/net/core/dev.c	2007-09-06 09:30:48.000000000 -0400
>@@ -1836,6 +1836,27 @@
> 
> 		have = netpoll_poll_lock(dev);
> 
>+		if (test_and_clear_bit(__LINK_STATE_NETPOLL_SERVICED, &dev->state)) {
>+			/*
>+			 * Seeing this bit set indicates that the netpoll code
>+			 * has handled this devices poll routine despite the fact
>+			 * that we have it on this cpu's poll_list.  Lets do 
>+			 * some fixup here to ensure that we don't have any 
>+			 * inconsistent state. 
>+			 */
>+			list_del(&dev->poll_list);
>+			clear_bit(__LINK_STATE_RX_SCHED, &dev->state);
>+			/*
>+			 * Check to see if any pending frames have come in
>+			 * while we were mucking about.  If they have lets reschedule
>+			 * this device
>+			 */
>+			if (dev->quota > 0)
>+				netif_rx_schedule(dev);
>+			netpoll_poll_unlock(have);
>+			continue;
>+		}
>+
> 		if (dev->quota <= 0 || dev->poll(dev, &budget)) {
> 			netpoll_poll_unlock(have);
> 			local_irq_disable();

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Attachments on bug 251978: 161198 | 181601 | 183141 | 183961 | 185531 | 185541 | 186681 | 187461 | 187831 | 189261 | 190311 | 190351 | 194551