Re: BUG: soft lockup detected on CPU#0! (2.6.18.2 plus hacks)
From: Ben Greear <hidden>
Date: 2007-01-03 23:35:52
David Stevens wrote:
Ben,
Here's a patch that I think will fix it, assuming the receive is
on the
same device as the initialization. Can you try this out?We are attempting to reproduce this now...as soon as we can reproduce, I'll apply this and see if that fixes the problem. This race is evidently quite difficult to hit, so I'm not sure how long this will take. Perhaps someone like DaveM could review the patch for logical correctness and go ahead and apply anyway if it is more correct? I confuse myself often enough trying to deal with the network stack locking that I should probably not be the final arbiter of this patch :) Thanks, Ben
quoted hunk ↗ jump to hunk
+-DLS [inline for viewing, attached for applying] Signed-off-by: David L Stevens <redacted> diff -ruNp linux-2.6.19.1/net/ipv4/devinet.c linux-2.6.19.1T1/net/ipv4/devinet.c--- linux-2.6.19.1/net/ipv4/devinet.c 2006-12-11 11:32:53.000000000 -0800 +++ linux-2.6.19.1T1/net/ipv4/devinet.c 2007-01-03 14:37:56.000000000 -0800@@ -165,9 +165,8 @@ struct in_device *inetdev_init(struct ne NET_IPV4_NEIGH, "ipv4", NULL, NULL); #endif - /* Account for reference dev->ip_ptr */ + /* Account for reference dev->ip_ptr (below) */ in_dev_hold(in_dev); - rcu_assign_pointer(dev->ip_ptr, in_dev); #ifdef CONFIG_SYSCTL devinet_sysctl_register(in_dev, &in_dev->cnf);@@ -176,6 +175,8 @@ struct in_device *inetdev_init(struct ne if (dev->flags & IFF_UP) ip_mc_up(in_dev); out: + /* we can receive as soon as ip_ptr is set -- do this last */ + rcu_assign_pointer(dev->ip_ptr, in_dev); return in_dev; out_kfree: kfree(in_dev);diff -ruNp linux-2.6.19.1/net/ipv6/addrconf.c linux-2.6.19.1T1/net/ipv6/addrconf.c--- linux-2.6.19.1/net/ipv6/addrconf.c 2006-12-11 11:32:53.000000000 -0800 +++ linux-2.6.19.1T1/net/ipv6/addrconf.c 2007-01-0314:47:07.000000000 -0800@@ -413,8 +413,6 @@ static struct inet6_dev * ipv6_add_dev(s if (netif_carrier_ok(dev)) ndev->if_flags |= IF_READY; - /* protected by rtnl_lock */ - rcu_assign_pointer(dev->ip6_ptr, ndev); ipv6_mc_init_dev(ndev); ndev->tstamp = jiffies;@@ -425,6 +423,8 @@ static struct inet6_dev * ipv6_add_dev(s NULL); addrconf_sysctl_register(ndev, &ndev->cnf); #endif + /* protected by rtnl_lock */ + rcu_assign_pointer(dev->ip6_ptr, ndev); return ndev; }
-- Ben Greear [off-list ref] Candela Technologies Inc http://www.candelatech.com