On Fri, 31 May 2019 14:54:54 +0200 Tomeu Vizoso tomeu@tomeuvizoso.net wrote:
On Wed, 29 May 2019 at 11:18, Boris Brezillon boris.brezillon@collabora.com wrote:
mmu_ops->unmap() will fail when called on a BO that has not been previously mapped, and the error path in panfrost_ioctl_create_bo() can call drm_gem_object_put_unlocked() (which in turn calls panfrost_mmu_unmap()) on a BO that has not been mapped yet.
Keep track of the mapped/unmapped state to avoid such issues.
Fixes: f3ba91228e8e ("drm/panfrost: Add initial panfrost driver") Cc: stable@vger.kernel.org Signed-off-by: Boris Brezillon boris.brezillon@collabora.com
drivers/gpu/drm/panfrost/panfrost_gem.h | 1 + drivers/gpu/drm/panfrost/panfrost_mmu.c | 8 ++++++++ 2 files changed, 9 insertions(+)
diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.h b/drivers/gpu/drm/panfrost/panfrost_gem.h index 045000eb5fcf..6dbcaba020fc 100644 --- a/drivers/gpu/drm/panfrost/panfrost_gem.h +++ b/drivers/gpu/drm/panfrost/panfrost_gem.h @@ -11,6 +11,7 @@ struct panfrost_gem_object { struct drm_gem_shmem_object base;
struct drm_mm_node node;
bool is_mapped;};
static inline diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.c b/drivers/gpu/drm/panfrost/panfrost_mmu.c index 762b1bd2a8c2..fb556aa89203 100644 --- a/drivers/gpu/drm/panfrost/panfrost_mmu.c +++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c @@ -156,6 +156,9 @@ int panfrost_mmu_map(struct panfrost_gem_object *bo) struct sg_table *sgt; int ret;
if (bo->is_mapped)return 0;In what circumstances we want to silently go on? I would expect that for this function to be called when the BO has been mapped already would mean that we have a bug in the kernel, so why not a WARN?
sgt = drm_gem_shmem_get_pages_sgt(obj); if (WARN_ON(IS_ERR(sgt))) return PTR_ERR(sgt);@@ -189,6 +192,7 @@ int panfrost_mmu_map(struct panfrost_gem_object *bo)
pm_runtime_mark_last_busy(pfdev->dev); pm_runtime_put_autosuspend(pfdev->dev);
bo->is_mapped = true; return 0;} @@ -203,6 +207,9 @@ void panfrost_mmu_unmap(struct panfrost_gem_object *bo) size_t unmapped_len = 0; int ret;
if (!bo->is_mapped)return;Similarly, I think that what we should do is not to call panfrost_mmu_unmap when a BO is freed if we know it isn't mapped. And probably add a WARN here if it still gets called when the BO isn't mapped.
Okay, will add WARN_ON()s and add a check in the caller.