diff --git a/internal/ceres/solver_test.cc b/internal/ceres/solver_test.cc
index f6fd9c7..0623903 100644
--- a/internal/ceres/solver_test.cc
+++ b/internal/ceres/solver_test.cc
@@ -375,6 +375,97 @@
   EXPECT_EQ(y, 1.0);
 }
 
+TEST(Solver, RepeatedSolvePreservesCallerLinearSolverOrdering) {
+  double x = 0.0;
+  double y = 0.0;
+  Problem problem;
+  problem.AddResidualBlock(QuadraticCostFunctor::Create(), nullptr, &x);
+  problem.AddResidualBlock(QuadraticCostFunctor::Create(), nullptr, &y);
+
+  Solver::Options options;
+  options.linear_solver_type = DENSE_SCHUR;
+  options.dense_linear_algebra_library_type = EIGEN;
+  options.function_tolerance = 0.0;
+  options.parameter_tolerance = 1e-12;
+  options.linear_solver_ordering = std::make_shared<ParameterBlockOrdering>();
+  options.linear_solver_ordering->AddElementToGroup(&x, 0);
+  options.linear_solver_ordering->AddElementToGroup(&y, 1);
+
+  // Fix x first; preprocessing must preserve its caller group.
+  problem.SetParameterBlockConstant(&x);
+  Solver::Summary summary;
+  Solve(options, &problem, &summary);
+  EXPECT_EQ(summary.termination_type, CONVERGENCE) << summary.message;
+  EXPECT_EQ(x, 0.0);
+  EXPECT_NEAR(y, 5.0, 1e-10);
+  EXPECT_EQ(options.linear_solver_ordering->GroupId(&x), 0);
+  EXPECT_EQ(options.linear_solver_ordering->GroupId(&y), 1);
+
+  // Re-enable x and solve with the same caller ordering.
+  problem.SetParameterBlockVariable(&x);
+  y = 0.0;
+  Solve(options, &problem, &summary);
+  EXPECT_EQ(summary.termination_type, CONVERGENCE) << summary.message;
+  EXPECT_NEAR(x, 5.0, 1e-10);
+  EXPECT_NEAR(y, 5.0, 1e-10);
+  EXPECT_EQ(options.linear_solver_ordering->GroupId(&x), 0);
+  EXPECT_EQ(options.linear_solver_ordering->GroupId(&y), 1);
+
+  // Check that a later solve also works without a supplied ordering.
+  options.linear_solver_ordering = nullptr;
+  x = 0.0;
+  y = 0.0;
+  Solve(options, &problem, &summary);
+  EXPECT_EQ(summary.termination_type, CONVERGENCE) << summary.message;
+  EXPECT_NEAR(x, 5.0, 1e-10);
+  EXPECT_NEAR(y, 5.0, 1e-10);
+}
+
+TEST(Solver, RepeatedSolvePreservesCallerInnerIterationOrdering) {
+  double x = 0.0;
+  double y = 0.0;
+  double z = 0.0;
+  Problem problem;
+  problem.AddResidualBlock(QuadraticCostFunctor::Create(), nullptr, &x);
+  problem.AddResidualBlock(QuadraticCostFunctor::Create(), nullptr, &y);
+  problem.AddResidualBlock(QuadraticCostFunctor::Create(), nullptr, &z);
+
+  Solver::Options options;
+  options.linear_solver_type = DENSE_QR;
+  options.use_inner_iterations = true;
+  options.function_tolerance = 0.0;
+  options.parameter_tolerance = 1e-12;
+  options.inner_iteration_ordering = std::make_shared<ParameterBlockOrdering>();
+  options.inner_iteration_ordering->AddElementToGroup(&x, 0);
+  options.inner_iteration_ordering->AddElementToGroup(&y, 1);
+  options.inner_iteration_ordering->AddElementToGroup(&z, 2);
+
+  // Fix x first; preprocessing must preserve its caller group.
+  problem.SetParameterBlockConstant(&x);
+  Solver::Summary summary;
+  Solve(options, &problem, &summary);
+  EXPECT_EQ(summary.termination_type, CONVERGENCE) << summary.message;
+  EXPECT_EQ(x, 0.0);
+  EXPECT_NEAR(y, 5.0, 1e-10);
+  EXPECT_NEAR(z, 5.0, 1e-10);
+  EXPECT_EQ(options.inner_iteration_ordering->GroupId(&x), 0);
+  EXPECT_EQ(options.inner_iteration_ordering->GroupId(&y), 1);
+  EXPECT_EQ(options.inner_iteration_ordering->GroupId(&z), 2);
+
+  // Re-enable x and solve with the same caller ordering.
+  problem.SetParameterBlockVariable(&x);
+  y = 0.0;
+  z = 0.0;
+  Solve(options, &problem, &summary);
+  EXPECT_EQ(summary.termination_type, CONVERGENCE) << summary.message;
+  EXPECT_NEAR(x, 5.0, 1e-10);
+  EXPECT_NEAR(y, 5.0, 1e-10);
+  EXPECT_NEAR(z, 5.0, 1e-10);
+  EXPECT_EQ(options.inner_iteration_ordering->GroupId(&x), 0);
+  EXPECT_EQ(options.inner_iteration_ordering->GroupId(&y), 1);
+  EXPECT_EQ(options.inner_iteration_ordering->GroupId(&z), 2);
+}
+
 TEST(Solver, DenseNormalCholeskyOptions) {
   std::string message;
   Solver::Options options;
diff --git a/internal/ceres/trust_region_preprocessor.cc b/internal/ceres/trust_region_preprocessor.cc
index 9d7a37d..a430c60 100644
--- a/internal/ceres/trust_region_preprocessor.cc
+++ b/internal/ceres/trust_region_preprocessor.cc
@@ -381,6 +381,18 @@
   EventLogger event_logger("TrustRegionPreprocessor::Preprocess");
   CHECK(pp != nullptr);
   pp->options = options;
+  // The options copy shares caller-owned orderings. Clone them before removing
+  // fixed parameter blocks during preprocessing.
+  if (pp->options.linear_solver_ordering != nullptr) {
+    pp->options.linear_solver_ordering =
+        std::make_shared<ParameterBlockOrdering>(
+            *pp->options.linear_solver_ordering);
+  }
+  if (pp->options.inner_iteration_ordering != nullptr) {
+    pp->options.inner_iteration_ordering =
+        std::make_shared<ParameterBlockOrdering>(
+            *pp->options.inner_iteration_ordering);
+  }
   ChangeNumThreadsIfNeeded(&pp->options);
 
   pp->problem = problem;