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Wed, 6 Nov 2024 13:18:15 +0100 (CET) Date: Wed, 6 Nov 2024 13:17:53 +0100 From: Boris Brezillon To: Liviu Dudau Cc: Steven Price , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Jann Horn Subject: Re: [PATCH] drm/panthor: Lock XArray when getting entries for heap and VM Message-ID: <20241106131753.6dbfc6da@collabora.com> In-Reply-To: <20241106120748.290697-1-liviu.dudau@arm.com> References: <20241106120748.290697-1-liviu.dudau@arm.com> Organization: Collabora X-Mailer: Claws Mail 4.3.0 (GTK 3.24.43; x86_64-redhat-linux-gnu) 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-Transfer-Encoding: 7bit On Wed, 6 Nov 2024 12:07:48 +0000 Liviu Dudau wrote: > Similar to cac075706f29 ("drm/panthor: Fix race when converting > group handle to group object") we need to use the XArray's internal > locking when retrieving a pointer from there for heap and vm. > > Reported-by: Jann Horn > Cc: Boris Brezillon > Cc: Steven Price > Signed-off-by: Liviu Dudau Missing Fixes tag. > --- > drivers/gpu/drm/panthor/panthor_heap.c | 15 +++++++++++++-- > drivers/gpu/drm/panthor/panthor_mmu.c | 2 ++ > 2 files changed, 15 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/panthor/panthor_heap.c b/drivers/gpu/drm/panthor/panthor_heap.c > index 3796a9eb22af2..fe0bcb6837f74 100644 > --- a/drivers/gpu/drm/panthor/panthor_heap.c > +++ b/drivers/gpu/drm/panthor/panthor_heap.c > @@ -351,6 +351,17 @@ int panthor_heap_create(struct panthor_heap_pool *pool, > return ret; > } > > +static struct panthor_heap *panthor_heap_from_id(struct pathor_heap_pool *pool, u32 id) > +{ > + struct panthor_heap *heap; > + > + xa_lock(&pool->xa); > + heap = xa_load(&pool->xa, id); > + xa_unlock(&pool->va); > + > + return heap; > +} > + > /** > * panthor_heap_return_chunk() - Return an unused heap chunk > * @pool: The pool this heap belongs to. > @@ -375,7 +386,7 @@ int panthor_heap_return_chunk(struct panthor_heap_pool *pool, > return -EINVAL; > > down_read(&pool->lock); > - heap = xa_load(&pool->xa, heap_id); > + heap = panthor_heap_from_id(pool, heap_id); > if (!heap) { > ret = -EINVAL; > goto out_unlock; > @@ -438,7 +449,7 @@ int panthor_heap_grow(struct panthor_heap_pool *pool, > return -EINVAL; > > down_read(&pool->lock); > - heap = xa_load(&pool->xa, heap_id); > + heap = panthor_heap_from_id(pool, heap_id); > if (!heap) { > ret = -EINVAL; > goto out_unlock; > diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c b/drivers/gpu/drm/panthor/panthor_mmu.c > index 8ca85526491e6..8b5cda9d21768 100644 > --- a/drivers/gpu/drm/panthor/panthor_mmu.c > +++ b/drivers/gpu/drm/panthor/panthor_mmu.c > @@ -1580,7 +1580,9 @@ panthor_vm_pool_get_vm(struct panthor_vm_pool *pool, u32 handle) > { > struct panthor_vm *vm; > > + xa_lock(&pool->xa); > vm = panthor_vm_get(xa_load(&pool->xa, handle)); > + xa_unlock(&pool->va); > > return vm; > }