Re: [PATCH v2] vfio: Follow a strict lifetime for struct iommu_group

Jason Gunthorpe
2022-10-04T17:22:17Z

On Tue, Oct 04, 2022 at 07:15:51PM +0200, Christian Borntraeger wrote:
>
> Am 04.10.22 um 18:28 schrieb Jason Gunthorpe:
> > On Tue, Oct 04, 2022 at 05:44:53PM +0200, Christian Borntraeger wrote:
> >
> > > > Does some userspace have the group FD open when it stucks like this,
> > > > eg what does fuser say?
> > >
> > > /proc/<virtnodedevd>/fd
> > > 51480 0 dr-x------. 2 root root 0 4. Okt 17:16 .
> > > 43593 0 dr-xr-xr-x. 9 root root 0 4. Okt 17:16 ..
> > > 65252 0 lr-x------. 1 root root 64 4. Okt 17:42 0 -> /dev/null
> > > 65253 0 lrwx------. 1 root root 64 4. Okt 17:42 1 -> 'socket:[51479]'
> > > 65261 0 lrwx------. 1 root root 64 4. Okt 17:42 10 -> 'anon_inode:[eventfd]'
> > > 65262 0 lrwx------. 1 root root 64 4. Okt 17:42 11 -> 'socket:[51485]'
> > > 65263 0 lrwx------. 1 root root 64 4. Okt 17:42 12 -> 'socket:[51487]'
> > > 65264 0 lrwx------. 1 root root 64 4. Okt 17:42 13 -> 'socket:[51486]'
> > > 65265 0 lrwx------. 1 root root 64 4. Okt 17:42 14 -> 'anon_inode:[eventfd]'
> > > 65266 0 lrwx------. 1 root root 64 4. Okt 17:42 15 -> 'socket:[60421]'
> > > 65267 0 lrwx------. 1 root root 64 4. Okt 17:42 16 -> 'anon_inode:[eventfd]'
> > > 65268 0 lrwx------. 1 root root 64 4. Okt 17:42 17 -> 'socket:[28008]'
> > > 65269 0 l-wx------. 1 root root 64 4. Okt 17:42 18 -> /run/libvirt/nodedev/driver.pid
> > > 65270 0 lrwx------. 1 root root 64 4. Okt 17:42 19 -> 'socket:[28818]'
> > > 65254 0 lrwx------. 1 root root 64 4. Okt 17:42 2 -> 'socket:[51479]'
> > > 65271 0 lr-x------. 1 root root 64 4. Okt 17:42 20 -> '/dev/vfio/3 (deleted)'
> >
> > Seems like a userspace bug to keep the group FD open after the /dev/
> > file has been deleted :|
> >
> > What do you think about this?
>
> On top of which tree is this?

It should apply on vfio-next

Jason