[PATCH v2] accel/amdxdna: fix NULL deref and GEM object leak in error paths

[Deniz Aydogan]

amdxdna_cmd_submit() does not set job->cmd_bo for internal driver
commands that pass AMDXDNA_INVALID_BO_HANDLE. When such a job hits
an error or completes normally, both the submit error path and
amdxdna_sched_job_cleanup() call amdxdna_gem_put_obj(job->cmd_bo)
unconditionally, dereferencing NULL.

Separately, amdxdna_cmd_set_error() acquires a GEM reference via
amdxdna_gem_get_obj() when handling a chained command, but leaks it
when the subsequent amdxdna_gem_vmap() returns NULL.

Guard all three amdxdna_gem_put_obj(job->cmd_bo) call sites with a
NULL check and release the GEM reference on vmap failure.

Fixes: 3ba13f5e7180 ("Merge tag 'devicetree-fixes-for-7.3-1'")
Signed-off-by: Deniz Aydogan <denizaydogan1902@xxxxxxxxx>
---
 drivers/accel/amdxdna/amdxdna_ctx.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/accel/amdxdna/amdxdna_ctx.c b/drivers/accel/amdxdna/amdxdna_ctx.c
index 31a414c3f..a806702ec 100644
--- a/drivers/accel/amdxdna/amdxdna_ctx.c
+++ b/drivers/accel/amdxdna/amdxdna_ctx.c
@@ -183,8 +183,10 @@ int amdxdna_cmd_set_error(struct amdxdna_gem_obj *abo,
 		if (!abo)
 			return -EINVAL;
 		cmd = amdxdna_gem_vmap(abo);
-		if (!cmd)
+		if (!cmd) {
+			amdxdna_gem_put_obj(abo);
 			return -ENOMEM;
+		}
 	}
 
 	memset(cmd->data, 0xff, abo->mem.size - sizeof(*cmd));
@@ -575,7 +577,8 @@ void amdxdna_sched_job_cleanup(struct amdxdna_sched_job *job)
 	trace_amdxdna_debug_point(job->hwctx->name, job->seq, "job release");
 	amdxdna_pm_suspend_put(job->hwctx->client->xdna);
 	amdxdna_arg_bos_put(job);
-	amdxdna_gem_put_obj(job->cmd_bo);
+	if (job->cmd_bo)
+		amdxdna_gem_put_obj(job->cmd_bo);
 	dma_fence_put(job->fence);
 	mmdrop(job->mm);
 }
@@ -676,7 +679,8 @@ int amdxdna_cmd_submit(struct amdxdna_client *client,
 put_bos:
 	amdxdna_arg_bos_put(job);
 cmd_put:
-	amdxdna_gem_put_obj(job->cmd_bo);
+	if (job->cmd_bo)
+		amdxdna_gem_put_obj(job->cmd_bo);
 free_job:
 	if (job->mm)
 		mmdrop(job->mm);
-- 
2.55.0