Re: [Qemu-devel] [PATCH] Fix issues affecting Xen 9pfs discovered by Coverity

[Stefano Stabellini]

On Mon, 8 May 2017, Eric Blake wrote:
> On 05/08/2017 03:45 PM, Stefano Stabellini wrote:
> > Fix two resource leaks on error paths, discovered by Coverity.
> > Check for errors returned by fcntl, also found by Coverity.
> > 
> > CID:1374836
> > CID:1374831
> > 
> 
> > @@ -378,7 +380,10 @@ static int xen_9pfs_connect(struct XenDevice *xendev)
> >          if (xen_9pdev->rings[i].evtchndev == NULL) {
> >              goto out;
> >          }
> > -        fcntl(xenevtchn_fd(xen_9pdev->rings[i].evtchndev), F_SETFD, 
> > FD_CLOEXEC);
> > +        if (fcntl(xenevtchn_fd(xen_9pdev->rings[i].evtchndev),
> > +                  F_SETFD, FD_CLOEXEC) == -1) {
> > +            goto out;
> 
> Directly calling fcntl(F_SETFD) without first reading fcntl(F_GETFD) is
> (theoretically) incorrect.  Better might be using qemu_set_cloexec()
> instead of open-coding something.

Makes sense but the unchecked return of fcntl, discovered by Coverity,
would remain unfixed by calling qemu_set_cloexec here. I don't think I
am up for fixing all the call sites of qemu_set_cloexec.

I am going to drop this change, and resend this patch was only the other
two fixes, fixing 1374836 only.