Skip to content

Conversation

@CoTinker
Copy link
Contributor

This PR fixes a crash caused by nullptr dereference in isContractionBody if reductionOp is nullptr. Fixes #162772.

This PR fixes a crash caused by nullptr dereference in `isContractionBody` if reductionOp is nullptr.
@llvmbot
Copy link
Member

llvmbot commented Oct 13, 2025

@llvm/pr-subscribers-mlir

@llvm/pr-subscribers-mlir-linalg

Author: Longsheng Mou (CoTinker)

Changes

This PR fixes a crash caused by nullptr dereference in isContractionBody if reductionOp is nullptr. Fixes #162772.


Full diff: https://github.com/llvm/llvm-project/pull/163132.diff

2 Files Affected:

  • (modified) mlir/lib/Dialect/Linalg/IR/LinalgInterfaces.cpp (+2-1)
  • (modified) mlir/test/Dialect/Linalg/match-ops-interpreter.mlir (+14)
diff --git a/mlir/lib/Dialect/Linalg/IR/LinalgInterfaces.cpp b/mlir/lib/Dialect/Linalg/IR/LinalgInterfaces.cpp
index c477c6cada2c9..dcc1ef9e997ea 100644
--- a/mlir/lib/Dialect/Linalg/IR/LinalgInterfaces.cpp
+++ b/mlir/lib/Dialect/Linalg/IR/LinalgInterfaces.cpp
@@ -315,7 +315,8 @@ bool mlir::linalg::detail::isContractionBody(
 
   Value yielded = getSourceSkipUnary(terminator->getOperand(0));
   Operation *reductionOp = yielded.getDefiningOp();
-  if (reductionOp->getNumResults() != 1 || reductionOp->getNumOperands() != 2) {
+  if (!reductionOp || reductionOp->getNumResults() != 1 ||
+      reductionOp->getNumOperands() != 2) {
     errs << "expected reduction op to be binary";
     return false;
   }
diff --git a/mlir/test/Dialect/Linalg/match-ops-interpreter.mlir b/mlir/test/Dialect/Linalg/match-ops-interpreter.mlir
index 618ba3402ff52..66cae5cfd923d 100644
--- a/mlir/test/Dialect/Linalg/match-ops-interpreter.mlir
+++ b/mlir/test/Dialect/Linalg/match-ops-interpreter.mlir
@@ -1011,6 +1011,20 @@ module attributes { transform.target_tag = "start_here" } {
     } -> tensor<1x1x4xf32>
     return
   }
+
+  func.func @generic_none(%arg0: tensor<128x128xi32>, %arg1: tensor<128x128xi32>, %arg2: tensor<128x128xi32>) {
+    %0 = linalg.generic {
+      indexing_maps = [affine_map<(d0, d1, d2) -> (d0, d2)>,
+                       affine_map<(d0, d1, d2) -> (d2, d1)>,
+                       affine_map<(d0, d1, d2) -> (d0, d1)>],
+      iterator_types = ["parallel", "parallel", "reduction"]}
+      ins(%arg0, %arg1 : tensor<128x128xi32>, tensor<128x128xi32>)
+      outs(%arg2 : tensor<128x128xi32>) {
+      ^bb0(%in: i32, %in_0: i32, %out: i32):
+        linalg.yield %out : i32
+      } -> tensor<128x128xi32>
+    return
+  }
 }
 
 // -----

Copy link
Contributor

@MaheshRavishankar MaheshRavishankar left a comment

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

It fixes a crash. and I am not opposed to the check here, but this seems like a strange operation. This is essentially an operation where %arg0 and %arg1 are unused.

@CoTinker
Copy link
Contributor Author

It fixes a crash. and I am not opposed to the check here, but this seems like a strange operation. This is essentially an operation where %arg0 and %arg1 are unused.

Yeah, this is an edge case, but it's still valid IR, so I think it's fine to use it as a test.

@CoTinker CoTinker merged commit 9a46060 into llvm:main Oct 15, 2025
13 checks passed
@CoTinker CoTinker deleted the nullptr branch October 15, 2025 03:06
@llvm-ci
Copy link
Collaborator

llvm-ci commented Oct 15, 2025

LLVM Buildbot has detected a new failure on builder mlir-nvidia running on mlir-nvidia while building mlir at step 7 "test-build-check-mlir-build-only-check-mlir".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/138/builds/20438

Here is the relevant piece of the build log for the reference
Step 7 (test-build-check-mlir-build-only-check-mlir) failure: test (failure)
******************** TEST 'MLIR :: Integration/GPU/CUDA/async.mlir' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 1
/vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt /vol/worker/mlir-nvidia/mlir-nvidia/llvm.src/mlir/test/Integration/GPU/CUDA/async.mlir  | /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt -gpu-kernel-outlining  | /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt -pass-pipeline='builtin.module(gpu.module(strip-debuginfo,convert-gpu-to-nvvm),nvvm-attach-target)'  | /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt -gpu-async-region -gpu-to-llvm -reconcile-unrealized-casts -gpu-module-to-binary="format=fatbin"  | /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt -async-to-async-runtime -async-runtime-ref-counting  | /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt -convert-async-to-llvm -convert-func-to-llvm -convert-arith-to-llvm -convert-cf-to-llvm -reconcile-unrealized-casts  | /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-runner    --shared-libs=/vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/lib/libmlir_cuda_runtime.so    --shared-libs=/vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/lib/libmlir_async_runtime.so    --shared-libs=/vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/lib/libmlir_runner_utils.so    --entry-point-result=void -O0  | /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/FileCheck /vol/worker/mlir-nvidia/mlir-nvidia/llvm.src/mlir/test/Integration/GPU/CUDA/async.mlir
# executed command: /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt /vol/worker/mlir-nvidia/mlir-nvidia/llvm.src/mlir/test/Integration/GPU/CUDA/async.mlir
# executed command: /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt -gpu-kernel-outlining
# executed command: /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt '-pass-pipeline=builtin.module(gpu.module(strip-debuginfo,convert-gpu-to-nvvm),nvvm-attach-target)'
# executed command: /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt -gpu-async-region -gpu-to-llvm -reconcile-unrealized-casts -gpu-module-to-binary=format=fatbin
# executed command: /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt -async-to-async-runtime -async-runtime-ref-counting
# executed command: /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt -convert-async-to-llvm -convert-func-to-llvm -convert-arith-to-llvm -convert-cf-to-llvm -reconcile-unrealized-casts
# executed command: /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-runner --shared-libs=/vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/lib/libmlir_cuda_runtime.so --shared-libs=/vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/lib/libmlir_async_runtime.so --shared-libs=/vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/lib/libmlir_runner_utils.so --entry-point-result=void -O0
# .---command stderr------------
# | 'cuStreamWaitEvent(stream, event, 0)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# | 'cuEventDestroy(event)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# | 'cuStreamWaitEvent(stream, event, 0)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# | 'cuEventDestroy(event)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# | 'cuStreamWaitEvent(stream, event, 0)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# | 'cuStreamWaitEvent(stream, event, 0)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# | 'cuEventDestroy(event)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# | 'cuEventDestroy(event)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# | 'cuEventSynchronize(event)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# | 'cuEventDestroy(event)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# `-----------------------------
# executed command: /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/FileCheck /vol/worker/mlir-nvidia/mlir-nvidia/llvm.src/mlir/test/Integration/GPU/CUDA/async.mlir
# .---command stderr------------
# | /vol/worker/mlir-nvidia/mlir-nvidia/llvm.src/mlir/test/Integration/GPU/CUDA/async.mlir:68:12: error: CHECK: expected string not found in input
# |  // CHECK: [84, 84]
# |            ^
# | <stdin>:1:1: note: scanning from here
# | Unranked Memref base@ = 0x5a168e81d070 rank = 1 offset = 0 sizes = [2] strides = [1] data = 
# | ^
# | <stdin>:2:1: note: possible intended match here
# | [42, 42]
# | ^
# | 
# | Input file: <stdin>
# | Check file: /vol/worker/mlir-nvidia/mlir-nvidia/llvm.src/mlir/test/Integration/GPU/CUDA/async.mlir
# | 
# | -dump-input=help explains the following input dump.
# | 
# | Input was:
# | <<<<<<
# |             1: Unranked Memref base@ = 0x5a168e81d070 rank = 1 offset = 0 sizes = [2] strides = [1] data =  
# | check:68'0     X~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ error: no match found
# |             2: [42, 42] 
# | check:68'0     ~~~~~~~~~
# | check:68'1     ?         possible intended match
...

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Projects

None yet

Development

Successfully merging this pull request may close these issues.

[mlir] null pointer SEGV in mlir/lib/Dialect/Linalg/IR/LinalgInterfaces.cpp

5 participants