From: Jason Gunthorpe <jgg@ziepe.ca>
To: Ralph Campbell <rcampbell@nvidia.com>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>,
Philip Yang <Philip.Yang@amd.com>,
Alex Deucher <alexander.deucher@amd.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
John Hubbard <jhubbard@nvidia.com>,
Ira Weiny <ira.weiny@intel.com>,
Dan Williams <dan.j.williams@intel.com>,
Arnd Bergmann <arnd@arndb.de>,
Balbir Singh <bsingharora@gmail.com>,
Dan Carpenter <dan.carpenter@oracle.com>,
Matthew Wilcox <willy@infradead.org>,
Souptick Joarder <jrdr.linux@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 4/5] mm/hmm: hmm_vma_fault() doesn't always call hmm_range_unregister()
Date: Thu, 6 Jun 2019 16:54:04 -0300 [thread overview]
Message-ID: <20190606195404.GJ17373@ziepe.ca> (raw)
In-Reply-To: <45c7f8ae-36b2-60cc-7d1d-d13ddd402d4b@nvidia.com>
On Thu, Jun 06, 2019 at 12:44:36PM -0700, Ralph Campbell wrote:
>
> On 6/6/19 7:50 AM, Jason Gunthorpe wrote:
> > On Mon, May 06, 2019 at 04:29:41PM -0700, rcampbell@nvidia.com wrote:
> > > From: Ralph Campbell <rcampbell@nvidia.com>
> > >
> > > The helper function hmm_vma_fault() calls hmm_range_register() but is
> > > missing a call to hmm_range_unregister() in one of the error paths.
> > > This leads to a reference count leak and ultimately a memory leak on
> > > struct hmm.
> > >
> > > Always call hmm_range_unregister() if hmm_range_register() succeeded.
> > >
> > > Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
> > > Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
> > > Cc: John Hubbard <jhubbard@nvidia.com>
> > > Cc: Ira Weiny <ira.weiny@intel.com>
> > > Cc: Dan Williams <dan.j.williams@intel.com>
> > > Cc: Arnd Bergmann <arnd@arndb.de>
> > > Cc: Balbir Singh <bsingharora@gmail.com>
> > > Cc: Dan Carpenter <dan.carpenter@oracle.com>
> > > Cc: Matthew Wilcox <willy@infradead.org>
> > > Cc: Souptick Joarder <jrdr.linux@gmail.com>
> > > Cc: Andrew Morton <akpm@linux-foundation.org>
> > > include/linux/hmm.h | 3 ++-
> > > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > > diff --git a/include/linux/hmm.h b/include/linux/hmm.h
> > > index 35a429621e1e..fa0671d67269 100644
> > > +++ b/include/linux/hmm.h
> > > @@ -559,6 +559,7 @@ static inline int hmm_vma_fault(struct hmm_range *range, bool block)
> > > return (int)ret;
> > > if (!hmm_range_wait_until_valid(range, HMM_RANGE_DEFAULT_TIMEOUT)) {
> > > + hmm_range_unregister(range);
> > > /*
> > > * The mmap_sem was taken by driver we release it here and
> > > * returns -EAGAIN which correspond to mmap_sem have been
> > > @@ -570,13 +571,13 @@ static inline int hmm_vma_fault(struct hmm_range *range, bool block)
> > > ret = hmm_range_fault(range, block);
> > > if (ret <= 0) {
> > > + hmm_range_unregister(range);
> >
> > While this seems to be a clear improvement, it seems there is still a
> > bug in nouveau_svm.c around here as I see it calls hmm_vma_fault() but
> > never calls hmm_range_unregister() for its on stack range - and
> > hmm_vma_fault() still returns with the range registered.
> >
> > As hmm_vma_fault() is only used by nouveau and is marked as
> > deprecated, I think we need to fix nouveau, either by dropping
> > hmm_range_fault(), or by adding the missing unregister to nouveau in
> > this patch.
>
> I will send a patch for nouveau to use hmm_range_register() and
> hmm_range_fault() and do some testing with OpenCL.
wow, thanks, I'd like to also really like to send such a thing through
hmm.git - do you know who the nouveau maintainers are so we can
collaborate on patch planning this?
> I can also send a separate patch to then remove hmm_vma_fault()
> but I guess that should be after AMD's changes.
Let us wait to hear back from AMD how they can consume hmm.git - I'd
very much like to get everything done in one kernel cycle!
Regards,
Jason
next prev parent reply other threads:[~2019-06-06 19:54 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-06 23:29 [PATCH 0/5] mm/hmm: HMM documentation updates and code fixes rcampbell
2019-05-06 23:29 ` [PATCH 1/5] mm/hmm: Update HMM documentation rcampbell
2019-06-06 14:02 ` Jason Gunthorpe
2019-06-06 18:50 ` Ralph Campbell
2019-06-06 19:32 ` Jason Gunthorpe
2019-05-06 23:29 ` [PATCH 2/5] mm/hmm: Clean up some coding style and comments rcampbell
2019-06-06 14:16 ` Jason Gunthorpe
2019-06-06 14:27 ` Jerome Glisse
2019-06-06 15:41 ` Jason Gunthorpe
2019-06-06 15:52 ` Jerome Glisse
2019-06-06 16:55 ` Joe Perches
2019-06-06 18:54 ` Jason Gunthorpe
2019-06-06 15:57 ` Jason Gunthorpe
2019-06-07 0:44 ` Ralph Campbell
2019-05-06 23:29 ` [PATCH 3/5] mm/hmm: Use mm_get_hmm() in hmm_range_register() rcampbell
2019-05-23 12:51 ` Jason Gunthorpe
2019-05-23 18:19 ` Ralph Campbell
2019-05-23 18:46 ` John Hubbard
2019-05-06 23:29 ` [PATCH 4/5] mm/hmm: hmm_vma_fault() doesn't always call hmm_range_unregister() rcampbell
2019-05-07 13:15 ` Souptick Joarder
2019-05-07 18:12 ` Ralph Campbell
2019-05-09 4:42 ` Souptick Joarder
2019-05-12 15:07 ` Jerome Glisse
2019-05-12 15:28 ` Jerome Glisse
2019-05-13 17:23 ` Ralph Campbell
2019-06-06 14:50 ` Jason Gunthorpe
2019-06-06 19:44 ` Ralph Campbell
2019-06-06 19:54 ` Jason Gunthorpe [this message]
2019-06-06 21:08 ` Ralph Campbell
2019-05-12 15:08 ` [PATCH 0/5] mm/hmm: HMM documentation updates and code fixes Jerome Glisse
2019-05-13 17:26 ` Ralph Campbell
2019-05-13 18:10 ` Jerome Glisse
2019-06-06 14:53 ` Jason Gunthorpe
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