On 11.08.2017 20:59, Thierry Reding wrote:
> From: Dmitry Osipenko <digetx@xxxxxxxxx>
>
> Since DRM IOCTL's are lockless, there is a chance that BOs could be
> released while a job submission is in progress. To avoid that, keep the
> GEM reference until the job has been pinned, part of which will be to
> take another reference.
>
> Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
> Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
> ---
> drivers/gpu/drm/tegra/drm.c | 42 +++++++++++++++++++++++++++++++++---------
> 1 file changed, 33 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
> index f01db33fa20f..e5d19e1c9bc8 100644
> --- a/drivers/gpu/drm/tegra/drm.c
> +++ b/drivers/gpu/drm/tegra/drm.c
> @@ -320,8 +320,6 @@ host1x_bo_lookup(struct drm_file *file, u32 handle)
> if (!gem)
> return NULL;
>
> - drm_gem_object_unreference_unlocked(gem);
> -
> bo = to_tegra_bo(gem);
> return &bo->base;
> }
> @@ -410,8 +408,10 @@ int tegra_drm_submit(struct tegra_drm_context *context,
> (void __user *)(uintptr_t)args->waitchks;
> struct drm_tegra_syncpt syncpt;
> struct host1x *host1x = dev_get_drvdata(drm->dev->parent);
> + struct drm_gem_object **refs;
Should be "**refs = NULL" in conjunction with a missed kfree() below.
> struct host1x_syncpt *sp;
> struct host1x_job *job;
> + unsigned int num_refs;
> int err;
>
> /* We don't yet support other than one syncpt_incr struct per submit */
> @@ -433,6 +433,26 @@ int tegra_drm_submit(struct tegra_drm_context *context,
> job->class = context->client->base.class;
> job->serialize = true;
>
> + /*
> + * Track referenced BOs so that they can be unreferenced after the
> + * submission is complete.
> + */
> + num_refs = num_cmdbufs + num_relocs * 2 + num_waitchks;
> +
> + if (sizeof(*refs) * num_refs > ULONG_MAX) {
> + err = -EINVAL;
> + goto fail;
> + }
> +
> + refs = kmalloc_array(num_refs, sizeof(*refs), GFP_KERNEL);
> + if (!refs) {
> + err = -ENOMEM;
> + goto fail;
> + }
> +
> + /* reuse as an iterator later */
> + num_refs = 0;
> +
> while (num_cmdbufs) {
> struct drm_tegra_cmdbuf cmdbuf;
> struct host1x_bo *bo;
> @@ -461,6 +481,7 @@ int tegra_drm_submit(struct tegra_drm_context *context,
>
> offset = (u64)cmdbuf.offset + (u64)cmdbuf.words * sizeof(u32);
> obj = host1x_to_tegra_bo(bo);
> + refs[num_refs++] = &obj->gem;
>
> /*
> * Gather buffer base address must be 4-bytes aligned,
> @@ -490,6 +511,7 @@ int tegra_drm_submit(struct tegra_drm_context *context,
>
> reloc = &job->relocarray[num_relocs];
> obj = host1x_to_tegra_bo(reloc->cmdbuf.bo);
> + refs[num_refs++] = &obj->gem;
>
> /*
> * The unaligned cmdbuf offset will cause an unaligned write
> @@ -503,6 +525,7 @@ int tegra_drm_submit(struct tegra_drm_context *context,
> }
>
> obj = host1x_to_tegra_bo(reloc->target.bo);
> + refs[num_refs++] = &obj->gem;
>
> if (reloc->target.offset >= obj->gem.size) {
> err = -EINVAL;
> @@ -522,6 +545,7 @@ int tegra_drm_submit(struct tegra_drm_context *context,
> goto fail;
>
> obj = host1x_to_tegra_bo(wait->bo);
> + refs[num_refs++] = &obj->gem;
>
> /*
> * The unaligned offset will cause an unaligned write during
> @@ -561,17 +585,17 @@ int tegra_drm_submit(struct tegra_drm_context *context,
> goto fail;
>
> err = host1x_job_submit(job);
> - if (err)
> - goto fail_submit;
> + if (err) {
> + host1x_job_unpin(job);
> + goto fail;
> + }
>
> args->fence = job->syncpt_end;
>
> - host1x_job_put(job);
> - return 0;
> -
> -fail_submit:
> - host1x_job_unpin(job);
> fail:
> + while (num_refs--)
> + drm_gem_object_put_unlocked(refs[num_refs]);
> +
kfree(refs) is missed here.
> host1x_job_put(job);
> return err;
> }
>
--
Dmitry
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