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[98.225.44.182]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-cb517ba214esm5042414a12.6.2026.07.20.11.49.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Jul 2026 11:49:11 -0700 (PDT) Date: Mon, 20 Jul 2026 11:49:09 -0700 From: Stanislav Kinsburskii To: Matthew Brost Cc: maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de, airlied@gmail.com, simona@ffwll.ch, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, intel-xe@lists.freedesktop.org Subject: Re: [PATCH] drm/gpusvm: Fix mm reference leak in range eviction Message-ID: References: <178406551216.1092539.5238081578161393168.stgit@skinsburskii> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Mon, Jul 20, 2026 at 11:42:19AM -0700, Matthew Brost wrote: > On Tue, Jul 14, 2026 at 02:45:14PM -0700, Stanislav Kinsburskii wrote: > > drm_gpusvm_range_evict() pins gpusvm->mm with mmget_not_zero() before > > allocating the temporary HMM PFN array. If that allocation fails, the > > function returns -ENOMEM directly and leaks the mm reference. > > > > Route the allocation failure through the common mmput() path after > > initializing err to -ENOMEM. This preserves the returned error while > > balancing the mm reference acquired by mmget_not_zero(). > > > > Fixes: 99624bdff8670 ("drm/gpusvm: Add support for GPU Shared Virtual Memory") > > Cc: stable@vger.kernel.org > > Signed-off-by: Stanislav Kinsburskii > > Yes, this is a bug... I also have pending patch to fix this here: > > https://patchwork.freedesktop.org/patch/740193/?series=170433&rev=1 > > I think I prefer mine. > Sure, let's disregard mine. Thanks, Stanislav > Matt > > > --- > > drivers/gpu/drm/drm_gpusvm.c | 5 +++-- > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/gpu/drm/drm_gpusvm.c b/drivers/gpu/drm/drm_gpusvm.c > > index 76e8a0028c7f..1a8bb83bd28d 100644 > > --- a/drivers/gpu/drm/drm_gpusvm.c > > +++ b/drivers/gpu/drm/drm_gpusvm.c > > @@ -1715,7 +1715,7 @@ int drm_gpusvm_range_evict(struct drm_gpusvm *gpusvm, > > unsigned long *pfns; > > unsigned long npages = npages_in_range(drm_gpusvm_range_start(range), > > drm_gpusvm_range_end(range)); > > - int err = 0; > > + int err = -ENOMEM; > > struct mm_struct *mm = gpusvm->mm; > > > > if (!mmget_not_zero(mm)) > > @@ -1723,12 +1723,13 @@ int drm_gpusvm_range_evict(struct drm_gpusvm *gpusvm, > > > > pfns = kvmalloc_array(npages, sizeof(*pfns), GFP_KERNEL); > > if (!pfns) > > - return -ENOMEM; > > + goto put_mm; > > > > hmm_range.hmm_pfns = pfns; > > err = hmm_range_fault_unlocked_timeout(&hmm_range, timeout); > > > > kvfree(pfns); > > +put_mm: > > mmput(mm); > > > > return err == -EBUSY ? -ETIME : err; > > > >