On Thu, 10 Feb 2011, Alex Williamson wrote:
> On Sun, 2011-02-06 at 21:11 +0100, Jesper Juhl wrote:
> > I believe that there's a small memory leak in
> > drivers/pci/intel-iommu.c:get_domain_for_dev().
> >
> > If the call to alloc_domain() succeeds but the subsequent call to
> > dmar_find_matched_drhd_unit() fails, then the current code will return
> > NULL without calling domain_exit(domain) which will leak the memory that
> > alloc_domain() allocated.
> >
> > The easy fix for that is to simply move the call to alloc_domain() below
> > the call to dmar_find_matched_drhd_unit() since the latter does not depend
> > on the former.
> >
> > I also made the change of moving the assignment to local variable 'iommu'
> > below both calls since there is no point in doing that work if either of
> > those those calls fail.
> >
> > I also changed the 'return NULL' in the dmar_find_matched_drhd_unit()
> > failure case to a 'goto error' since I figured that if rechecking
> > 'find_domain(pdev)' makes sense after a alloc_domain() failure then it
> > would also make sense after a dmar_find_matched_drhd_unit() failure.
>
> I don't think this change buys us anything. The goto error here seems
> to be a hope that another cpu may have beat us and succeeded at
> something we failed. In the case of matching the pci device to a drhd,
> this should be deterministic (unless maybe we're racing a hot added
> drhd). The rest seems fine to me. Thanks,
>
> Alex
>
Ok. Updated patch below that leaves out the 'goto error' bit for
dmar_find_matched_drhd_unit() failures.
There is a small memory leak in
drivers/pci/intel-iommu.c:get_domain_for_dev().
If the call to alloc_domain() succeeds but the subsequent call to
dmar_find_matched_drhd_unit() fails, then the current code will return
NULL without calling domain_exit(domain) which will leak the memory that
alloc_domain() allocated.
The easy fix for that is to simply move the call to alloc_domain() below
the call to dmar_find_matched_drhd_unit() since the latter does not depend
on the former.
Signed-off-by: Jesper Juhl <jj@xxxxxxxxxxxxx>
---
intel-iommu.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index 4789f8e..3cfb021 100644
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -1820,10 +1820,6 @@ static struct dmar_domain *get_domain_for_dev(struct pci_dev *pdev, int gaw)
}
}
- domain = alloc_domain();
- if (!domain)
- goto error;
-
/* Allocate new domain for the device */
drhd = dmar_find_matched_drhd_unit(pdev);
if (!drhd) {
@@ -1831,8 +1827,11 @@ static struct dmar_domain *get_domain_for_dev(struct pci_dev *pdev, int gaw)
pci_name(pdev));
return NULL;
}
- iommu = drhd->iommu;
+ domain = alloc_domain();
+ if (!domain)
+ goto error;
+ iommu = drhd->iommu;
ret = iommu_attach_domain(domain, iommu);
if (ret) {
domain_exit(domain);
--
Jesper Juhl <jj@xxxxxxxxxxxxx> http://www.chaosbits.net/
Plain text mails only, please.
Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html
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