Re: [PATCH 12/62] drm/gpusvm.c: Fix a locking bug in an error path

[Bart Van Assche]

On 2/23/26 2:11 PM, Matthew Brost wrote:
> On Mon, Feb 23, 2026 at 02:00:12PM -0800, Bart Van Assche wrote:
> > From: Bart Van Assche <bvanassche@xxxxxxx>
> >
> > Only call drm_gpusvm_notifier_unlock() if drm_gpusvm_notifier_lock() was
> > called first. This has been detected by the Clang thread-safety
> > analyzer. Compile-tested only.
> >
> > Cc: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
> > Cc: Matthew Brost <matthew.brost@xxxxxxxxx>
> > Cc: Himal Prasad Ghimiray <himal.prasad.ghimiray@xxxxxxxxx>
> > Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
> > Fixes: f1d08a586482 ("drm/gpusvm: Introduce a function to scan the current migration state")
> > Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
> > ---
> >   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 24180bfdf5a2..e9b79ab2f83c 100644
> > --- a/drivers/gpu/drm/drm_gpusvm.c
> > +++ b/drivers/gpu/drm/drm_gpusvm.c
> > @@ -819,7 +819,7 @@ enum drm_gpusvm_scan_result drm_gpusvm_scan_mm(struct drm_gpusvm_range *range,
> >   
> >   		if (!(pfns[i] & HMM_PFN_VALID)) {
> >   			state = DRM_GPUSVM_SCAN_UNPOPULATED;
> > -			goto err_free;
> > +			goto unlock;
>
> Indeed a problem but we have this fixed in drm-tip.
>
> git format-patch -1 d287dee565c3c
>
> 'drm/gpusvm: Fix unbalanced unlock in drm_gpusvm_scan_mm'
>
> Not sure which tree you are in but this should propagate up to Linus
> during the 7.0 cycle.

Thanks Matt for the quick follow-up. This patch series is based on
Linus' master branch. Since a fix has already been queued in the drm-tip
branch, I will drop this patch.

Bart.