From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: Re: [PATCH] x86/MSI: fix locking in pci_restore_msi_state() Date: Fri, 11 Oct 2013 10:02:43 +0100 Message-ID: <5257BEB3.2070703@citrix.com> References: <5257D70202000078000FA775@nat28.tlf.novell.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============6788337356343930197==" Return-path: Received: from mail6.bemta3.messagelabs.com ([195.245.230.39]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1VUYcR-0005EB-0r for xen-devel@lists.xenproject.org; Fri, 11 Oct 2013 09:02:47 +0000 In-Reply-To: <5257D70202000078000FA775@nat28.tlf.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Jan Beulich Cc: xen-devel , Keir Fraser , Kristoffer Egefelt List-Id: xen-devel@lists.xenproject.org --===============6788337356343930197== Content-Type: multipart/alternative; boundary="------------060305020709050907000005" --------------060305020709050907000005 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit On 11/10/2013 09:46, Jan Beulich wrote: > Right after the loop the lock is being dropped, so all loop exits > should happen with the lock still held. > > Reported-by: Kristoffer Egefelt > Signed-off-by: Jan Beulich > Tested-by: Kristoffer Egefelt Reviewed-by: Andrew Cooper > > --- a/xen/arch/x86/msi.c > +++ b/xen/arch/x86/msi.c > @@ -1158,11 +1158,11 @@ int pci_restore_msi_state(struct pci_dev > for ( i = 0; ; ) > { > msi_set_mask_bit(desc, entry[i].msi_attrib.masked); > - spin_unlock_irqrestore(&desc->lock, flags); > > if ( !--nr ) > break; > > + spin_unlock_irqrestore(&desc->lock, flags); > desc = &irq_desc[entry[++i].irq]; > spin_lock_irqsave(&desc->lock, flags); > if ( desc->msi_desc != entry + i ) > > > > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xen.org > http://lists.xen.org/xen-devel --------------060305020709050907000005 Content-Type: text/html; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit
On 11/10/2013 09:46, Jan Beulich wrote:
Right after the loop the lock is being dropped, so all loop exits
should happen with the lock still held.

Reported-by: Kristoffer Egefelt <kristoffer@itoc.dk>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Tested-by: Kristoffer Egefelt <kristoffer@itoc.dk>

Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>


--- a/xen/arch/x86/msi.c
+++ b/xen/arch/x86/msi.c
@@ -1158,11 +1158,11 @@ int pci_restore_msi_state(struct pci_dev
         for ( i = 0; ; )
         {
             msi_set_mask_bit(desc, entry[i].msi_attrib.masked);
-            spin_unlock_irqrestore(&desc->lock, flags);
 
             if ( !--nr )
                 break;
 
+            spin_unlock_irqrestore(&desc->lock, flags);
             desc = &irq_desc[entry[++i].irq];
             spin_lock_irqsave(&desc->lock, flags);
             if ( desc->msi_desc != entry + i )






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