From mboxrd@z Thu Jan 1 00:00:00 1970 From: Veaceslav Falico Subject: Re: [PATCH net-next] bonding: make slave status notifications GFP_ATOMIC Date: Thu, 6 Mar 2014 14:22:25 +0100 Message-ID: <20140306132225.GC4773@redhat.com> References: <1394025353-5496-1-git-send-email-vfalico@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Cc: Thomas Glanzmann , Ding Tianhong , Jay Vosburgh , Andy Gospodarek To: netdev@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:10006 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751049AbaCFNWl (ORCPT ); Thu, 6 Mar 2014 08:22:41 -0500 Content-Disposition: inline In-Reply-To: <1394025353-5496-1-git-send-email-vfalico@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, Mar 05, 2014 at 02:15:53PM +0100, Veaceslav Falico wrote: >Currently we're using GFP_KERNEL, however there are some path(s) where we >can hold some spinlocks, specifically bond->curr_slave_lock: > >[ 4.722916] BUG: sleeping function called from invalid context at mm/slub.c:965 >[ 4.724438] in_atomic(): 1, irqs_disabled(): 0, pid: 940, name: ifup-eth >[ 4.726034] 5 locks held by ifup-eth/940: >...snip... >[ 4.734646] #4: (&bond->curr_slave_lock){+...+.}, at: [] bond_enslave+0xda6/0xdd0 [bonding] >...snip... >[ 4.759081] [] bond_change_active_slave+0x191/0x3b0 [bonding] >[ 4.760917] [] bond_select_active_slave+0xf7/0x1d0 [bonding] >[ 4.762751] [] bond_enslave+0xdae/0xdd0 [bonding] >...snip... > >As it's out of hot path and is a really rare event - change the gfp_t flags >to GFP_ATOMIC to avoid sleeping under spinlock. > >CC: Thomas Glanzmann >CC: Ding Tianhong >CC: Jay Vosburgh >CC: Andy Gospodarek >Signed-off-by: Veaceslav Falico Self-NAK as the net got synced and there is a conflicting fix from 5e5b0665 ("bonding: Fix RTNL: assertion failed at net/core/rtnetlink.c for 802.3ad mode"), which adds a lot of complexity, postpones the notifications (and makes them kind of useless cause the state might have been changed again), and still doesn't fix all the cases. I'll re-send the patchset. >--- > drivers/net/bonding/bonding.h | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > >diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h >index 4303628..4cd451d 100644 >--- a/drivers/net/bonding/bonding.h >+++ b/drivers/net/bonding/bonding.h >@@ -292,7 +292,7 @@ static inline void bond_set_active_slave(struct slave *slave) > { > if (slave->backup) { > slave->backup = 0; >- rtmsg_ifinfo(RTM_NEWLINK, slave->dev, 0, GFP_KERNEL); >+ rtmsg_ifinfo(RTM_NEWLINK, slave->dev, 0, GFP_ATOMIC); > } > } > >@@ -300,7 +300,7 @@ static inline void bond_set_backup_slave(struct slave *slave) > { > if (!slave->backup) { > slave->backup = 1; >- rtmsg_ifinfo(RTM_NEWLINK, slave->dev, 0, GFP_KERNEL); >+ rtmsg_ifinfo(RTM_NEWLINK, slave->dev, 0, GFP_ATOMIC); > } > } > >-- >1.8.4 >