drm/i915/gem: Do not leak siblings[] on proto context error

After a successful BALANCE/PARALLEL_SUBMIT extension on context
creation, error during processing of next user extension leaks
the siblings[] array. Fix that.

Discovered using AI-assisted static analysis confirmed by
Intel Product Security.

Reported-by: Martin Hodo <martin.hodo@intel.com>
Fixes: d4433c7600f7 ("drm/i915/gem: Use the proto-context to handle create parameters (v5)")
Cc: Faith Ekstrand <faith.ekstrand@collabora.com>
Cc: Simona Vetter <simona.vetter@ffwll.ch>
Cc: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: <stable@vger.kernel.org> # v5.15+
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Tvrtko Ursulin <tursulin@ursulin.net>
Link: https://lore.kernel.org/r/20260701073030.44850-1-joonas.lahtinen@linux.intel.com
(cherry picked from commit aa65e0a4b51b3b54b53e4142aaa2d997aa1061ff)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
index 347d1f2c05f502529fa385f8114f3df14231de59..c58ffa5a8fa6f51178add1a668578b2a46f42eed 100644 (file)
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
@@ -769,8 +769,8 @@ static int set_proto_ctx_engines(struct drm_i915_file_private *fpriv,
                struct intel_engine_cs *engine;
 
                if (copy_from_user(&ci, &user->engines[n], sizeof(ci))) {
-                       kfree(set.engines);
-                       return -EFAULT;
+                       err = -EFAULT;
+                       goto err;
                }
 
                memset(&set.engines[n], 0, sizeof(set.engines[n]));
@@ -786,8 +786,8 @@ static int set_proto_ctx_engines(struct drm_i915_file_private *fpriv,
                        drm_dbg(&i915->drm,
                                "Invalid engine[%d]: { class:%d, instance:%d }\n",
                                n, ci.engine_class, ci.engine_instance);
-                       kfree(set.engines);
-                       return -ENOENT;
+                       err = -ENOENT;
+                       goto err;
                }
 
                set.engines[n].type = I915_GEM_ENGINE_TYPE_PHYSICAL;
@@ -800,15 +800,21 @@ static int set_proto_ctx_engines(struct drm_i915_file_private *fpriv,
                                           set_proto_ctx_engines_extensions,
                                           ARRAY_SIZE(set_proto_ctx_engines_extensions),
                                           &set);
-       if (err) {
-               kfree(set.engines);
-               return err;
-       }
+       if (err)
+               goto err_extensions;
 
        pc->num_user_engines = set.num_engines;
        pc->user_engines = set.engines;
 
        return 0;
+
+err_extensions:
+       for (n = 0; n < set.num_engines; n++)
+               kfree(set.engines[n].siblings);
+err:
+       kfree(set.engines);
+
+       return err;
 }
 
 static int set_proto_ctx_sseu(struct drm_i915_file_private *fpriv,