linux-kernel - [PATCH v3] drm/msm: Fix submit error-path leaks

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Message-Id: <20230509172253.383964-1-robdclark@gmail.com>
Date:   Tue,  9 May 2023 10:22:53 -0700
From:   Rob Clark <robdclark@...il.com>
To:     dri-devel@...ts.freedesktop.org
Cc:     freedreno@...ts.freedesktop.org, linux-arm-msm@...r.kernel.org,
        Rob Clark <robdclark@...omium.org>, pinkperfect2021@...il.com,
        Rob Clark <robdclark@...il.com>,
        Abhinav Kumar <quic_abhinavk@...cinc.com>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Sean Paul <sean@...rly.run>, David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        linux-kernel@...r.kernel.org (open list)
Subject: [PATCH v3] drm/msm: Fix submit error-path leaks

From: Rob Clark <robdclark@...omium.org>

For errors after msm_submitqueue_get(), we need to drop the submitqueue
reference.  Additionally after get_unused_fd() we need to drop the fd.
The ordering for dropping the queue lock and put_unused_fd() is not
important, so just move this all into out_post_unlock.

v2: Only drop queue ref if submit doesn't take it
v3: Fix unitialized submit ref in error path

Reported-by: pinkperfect2021@...il.com
Fixes: f0de40a131d9 drm/msm: ("Reorder lock vs submit alloc")
Signed-off-by: Rob Clark <robdclark@...omium.org>
---
 drivers/gpu/drm/msm/msm_gem_submit.c | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_gem_submit.c b/drivers/gpu/drm/msm/msm_gem_submit.c
index 6c6aefaa72be..c994d4a13580 100644
--- a/drivers/gpu/drm/msm/msm_gem_submit.c
+++ b/drivers/gpu/drm/msm/msm_gem_submit.c
@@ -720,21 +720,21 @@ static void msm_process_post_deps(struct msm_submit_post_dep *post_deps,
 		}
 	}
 }
 
 int msm_ioctl_gem_submit(struct drm_device *dev, void *data,
 		struct drm_file *file)
 {
 	struct msm_drm_private *priv = dev->dev_private;
 	struct drm_msm_gem_submit *args = data;
 	struct msm_file_private *ctx = file->driver_priv;
-	struct msm_gem_submit *submit;
+	struct msm_gem_submit *submit = NULL;
 	struct msm_gpu *gpu = priv->gpu;
 	struct msm_gpu_submitqueue *queue;
 	struct msm_ringbuffer *ring;
 	struct msm_submit_post_dep *post_deps = NULL;
 	struct drm_syncobj **syncobjs_to_reset = NULL;
 	int out_fence_fd = -1;
 	bool has_ww_ticket = false;
 	unsigned i;
 	int ret;
 
@@ -767,27 +767,29 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data,
 	queue = msm_submitqueue_get(ctx, args->queueid);
 	if (!queue)
 		return -ENOENT;
 
 	ring = gpu->rb[queue->ring_nr];
 
 	if (args->flags & MSM_SUBMIT_FENCE_FD_OUT) {
 		out_fence_fd = get_unused_fd_flags(O_CLOEXEC);
 		if (out_fence_fd < 0) {
 			ret = out_fence_fd;
-			return ret;
+			goto out_post_unlock;
 		}
 	}
 
 	submit = submit_create(dev, gpu, queue, args->nr_bos, args->nr_cmds);
-	if (IS_ERR(submit))
-		return PTR_ERR(submit);
+	if (IS_ERR(submit)) {
+		ret = PTR_ERR(submit);
+		goto out_post_unlock;
+	}
 
 	trace_msm_gpu_submit(pid_nr(submit->pid), ring->id, submit->ident,
 		args->nr_bos, args->nr_cmds);
 
 	ret = mutex_lock_interruptible(&queue->lock);
 	if (ret)
 		goto out_post_unlock;
 
 	if (args->flags & MSM_SUBMIT_SUDO)
 		submit->in_rb = true;
@@ -962,25 +964,33 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data,
 	msm_reset_syncobjs(syncobjs_to_reset, args->nr_in_syncobjs);
 	msm_process_post_deps(post_deps, args->nr_out_syncobjs,
 	                      submit->user_fence);
 
 
 out:
 	submit_cleanup(submit, !!ret);
 	if (has_ww_ticket)
 		ww_acquire_fini(&submit->ticket);
 out_unlock:
-	if (ret && (out_fence_fd >= 0))
-		put_unused_fd(out_fence_fd);
 	mutex_unlock(&queue->lock);
 out_post_unlock:
-	msm_gem_submit_put(submit);
+	if (ret && (out_fence_fd >= 0))
+		put_unused_fd(out_fence_fd);
+	if (submit) {
+		msm_gem_submit_put(submit);
+	} else {
+		/*
+		 * If the submit hasn't yet taken ownership of the queue
+		 * then we need to drop the reference ourself:
+		 */
+		msm_submitqueue_put(queue);
+	}
 	if (!IS_ERR_OR_NULL(post_deps)) {
 		for (i = 0; i < args->nr_out_syncobjs; ++i) {
 			kfree(post_deps[i].chain);
 			drm_syncobj_put(post_deps[i].syncobj);
 		}
 		kfree(post_deps);
 	}
 
 	if (!IS_ERR_OR_NULL(syncobjs_to_reset)) {
 		for (i = 0; i < args->nr_in_syncobjs; ++i) {
-- 
2.40.1