Hi David, >-----Original Message----- >From: David Marchand <[email protected]> >Sent: Wednesday, October 27, 2021 10:49 PM >To: Burakov, Anatoly <[email protected]>; Ding, Xuan ><[email protected]> >Cc: dev <[email protected]>; Maxime Coquelin <[email protected]> >Subject: Re: [dpdk-dev] [PATCH v1 1/1] vfio: fix partial unmap check > >On Tue, Oct 26, 2021 at 3:30 PM Anatoly Burakov ><[email protected]> wrote: >> >> Partial unmap support was introduced in commit c13ca4e81cac, and with it >> was added a check that dereferenced the IOMMU type to determine >whether >> partial ummapping is supported for currently configured IOMMU type. In >> certain circumstances (such as when VFIO is supported, but no devices >> were bound to the VFIO driver), the IOMMU type pointer can be NULL. >> >> However, dereferencing of IOMMU type was guarded by access to the user >> maps list - that is, we were always checking the user map list first, >> and then, if we found a memory region that encloses the one we're trying >> to unmap, we would have performed the IOMMU type check. >> >> This ensured that the IOMMU type check will not cause any NULL pointer >> dereferences, because in order for an IOMMU type check to have been >> performed, there necessarily must have been at least one memory region >> that was previously mapped successfully, and that implies having a >> defined IOMMU type. >> >> When 56259f7fc010 was introduced, the IOMMU type check was moved to >> before we were traversing the user mem maps list, thereby introducing a >> potential NULL dereference, because the IOMMU type access was no longer >> guarded by the user mem maps list traversal. >> >> Fix the issue by moving the IOMMU type check to after the user mem maps >> traversal, thereby ensuring that by the time the check happens, the >> IOMMU type is always valid. >> >> Fixes: 56259f7fc010 ("vfio: allow partially unmapping adjacent memory") >> Cc: [email protected] >> >> Signed-off-by: Anatoly Burakov <[email protected]> >Reviewed-by: David Marchand <[email protected]> > >I guess Xuan tested it too, since we have a vhost patch on top of this >vfio patch. >Can you just confirm it is ok to merge?
Yes, I tested it and it works fine. Tested-by: Xuan Ding <[email protected]> Regards, Xuan > >Thanks. > > >-- >David Marchand
