diff --git a/dnn/include/megdnn/oprs/general.h b/dnn/include/megdnn/oprs/general.h
index 4b1c28871df99c1d0f713d1ecef1a1e1a8b87d1b..829d5395f6177ca37ae5c8ff98dd79133284db49 100644
--- a/dnn/include/megdnn/oprs/general.h
+++ b/dnn/include/megdnn/oprs/general.h
@@ -1317,6 +1317,27 @@ protected:
                             TensorLayout& exec_workspace,
                             TensorLayout& exec_src, TensorLayout& exec_dst);
 };
+
+/*!
+ * \brief check whether input contains inf value.
+ */
+class CheckHasInf: public OperatorBase {
+    DEF_OPR_PARAM(Empty);
+    DEF_OPR_IMPL(CheckHasInf, OperatorBase, 1, 1);
+
+    public:
+        virtual size_t get_workspace_in_bytes(const TensorLayout &src,
+                const TensorLayout &dst) = 0;
+
+        void deduce_layout(const TensorLayout &src, TensorLayout &dst);
+
+        virtual void exec(_megdnn_tensor_in src, _megdnn_tensor_out dst,
+                _megdnn_workspace workspace) = 0;
+
+    protected:
+        void check_exec(const TensorLayout &src, const TensorLayout &dst,
+                size_t workspace_in_bytes);
+};
 }  // namespace megdnn
 
 #include "megdnn/internal/opr_header_epilogue.h"
diff --git a/dnn/src/common/check_has_inf.cpp b/dnn/src/common/check_has_inf.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..66f1a63c91ad271aa1a8ef0fd4d4496aaccb544a
--- /dev/null
+++ b/dnn/src/common/check_has_inf.cpp
@@ -0,0 +1,36 @@
+/**
+ * \file dnn/src/common/check_has_inf.cpp
+ * MegEngine is Licensed under the Apache License, Version 2.0 (the "License")
+ *
+ * Copyright (c) 2014-2021 Megvii Inc. All rights reserved.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * ARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ */
+
+#include "megdnn/oprs.h"
+#include "src/common/utils.h"
+
+namespace megdnn {
+
+void CheckHasInf::check_exec(const TensorLayout& src, const TensorLayout& dst,
+                             size_t workspace_in_bytes) {
+    megdnn_assert_contiguous(src);
+    megdnn_assert_contiguous(dst);
+    megdnn_assert(src.ndim == 1);
+    megdnn_assert(src.dtype == dtype::Float32());
+    auto required_workspace_in_bytes = get_workspace_in_bytes(src, dst);
+    megdnn_assert(workspace_in_bytes >= required_workspace_in_bytes);
+}
+
+void CheckHasInf::deduce_layout(const TensorLayout&, TensorLayout& dst) {
+    dst.shape[0] = 1;
+    dst.ndim = 1;
+    dst.dtype = dtype::Int32();
+    dst.init_contiguous_stride();
+}
+
+}  // namespace megdnn
+
+// vim: syntax=cpp.doxygen
diff --git a/dnn/src/common/handle_impl.h b/dnn/src/common/handle_impl.h
index e05449abfa8a96b4f5501213f77055870fc20ba5..4d6354e3baebdcd0e7f13350eb9dfec8c8a15dd2 100644
--- a/dnn/src/common/handle_impl.h
+++ b/dnn/src/common/handle_impl.h
@@ -207,7 +207,8 @@ private:
     cb(FakeQuantForward) \
     cb(FakeQuantBackward) \
     cb(TQTForward) \
-    cb(TQTBackward)
+    cb(TQTBackward) \
+    cb(CheckHasInf)
 
 /*!
  * \brief specialize HandleImpl::create_operator for a single opr type;
diff --git a/dnn/src/common/opr_trait.h b/dnn/src/common/opr_trait.h
index 0642345e126b75bcb5a6d941c6ac7e9443b00b54..313bac68b5015f53f9a4a6165e4694e5d5181df4 100644
--- a/dnn/src/common/opr_trait.h
+++ b/dnn/src/common/opr_trait.h
@@ -120,6 +120,7 @@ DEF(PowC, 2, false, true);
 DEF(UniformRNG, 1, true, true);
 DEF(GaussianRNG, 1, true, true);
 DEF(ChecksumForward, 1, true, false);
+DEF(CheckHasInf, 2, true, true);
 }  // namespace megdnn
 
 // vim: syntax=cpp.doxygen
diff --git a/dnn/src/common/reduce_helper.h b/dnn/src/common/reduce_helper.h
index c7cd689027619cacb6b2a4f192205b18c18bff4d..08d4fc473cb374259b75c5592e707089d696107a 100644
--- a/dnn/src/common/reduce_helper.h
+++ b/dnn/src/common/reduce_helper.h
@@ -4,9 +4,9 @@
  *
  * Copyright (c) 2014-2021 Megvii Inc. All rights reserved.
  *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT ARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * ARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  */
 #pragma once
 #include "megdnn/dtype.h"
@@ -151,6 +151,33 @@ struct MaxOp {
             : INIT(wtype(DTypeTrait<wtype>::min())), src(src), dst(dst), B(B) {}
 };
 
+template <typename src_ctype, typename dst_ctype, typename wtype_>
+struct CheckHasInfOp {
+    typedef wtype_ wtype;
+    const wtype INIT;
+
+    src_ctype* src;
+    dst_ctype* dst;
+    const size_t B;
+
+    MEGDNN_HOST MEGDNN_DEVICE wtype read(uint32_t idx) {
+#if defined(__CUDA_ARCH__)
+        return isinf(src[idx]);
+#else
+        return std::isinf(src[idx]);
+#endif
+    }
+    MEGDNN_HOST MEGDNN_DEVICE void write(uint32_t idx, wtype val) {
+        dst[idx] = val;
+    }
+    static MEGDNN_HOST MEGDNN_DEVICE wtype apply(wtype lhs, wtype rhs) {
+        return lhs | rhs;
+    }
+    MEGDNN_HOST MEGDNN_DEVICE CheckHasInfOp(src_ctype* src, dst_ctype* dst,
+                                            size_t B)
+            : INIT(wtype(0)), src(src), dst(dst), B(B) {}
+};
+
 #if MEGDNN_CC_HOST
 void get_ABC(const TensorShape& shape, size_t& A, size_t& B, size_t& C,
              size_t axis);
diff --git a/dnn/src/cuda/check_has_inf/kern.cu b/dnn/src/cuda/check_has_inf/kern.cu
new file mode 100644
index 0000000000000000000000000000000000000000..cb3d1049529b88e7237b06876ea1f3aade393452
--- /dev/null
+++ b/dnn/src/cuda/check_has_inf/kern.cu
@@ -0,0 +1,27 @@
+/**
+ * \file dnn/src/cuda/check_has_inf/kern.cu
+ * MegEngine is Licensed under the Apache License, Version 2.0 (the "License")
+ *
+ * Copyright (c) 2014-2021 Megvii Inc. All rights reserved.
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT ARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ */
+#include "src/common/reduce_helper.h"
+
+#include "megdnn/dtype.h"
+#include "src/cuda/reduce_helper.cuh"
+
+namespace megdnn {
+namespace cuda {
+
+#define COMMA ,
+
+INST_REDUCE(reduce::CheckHasInfOp<dt_float32 COMMA dt_int32 COMMA dt_int32>, false);
+
+#undef COMMA
+} // namespace cuda
+} // namespace megdnn
+
+// vim: ft=cpp syntax=cpp.doxygen
diff --git a/dnn/src/cuda/check_has_inf/opr_impl.cpp b/dnn/src/cuda/check_has_inf/opr_impl.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..bf44be610ac1a024dc2fed72f8645c9eae5236fc
--- /dev/null
+++ b/dnn/src/cuda/check_has_inf/opr_impl.cpp
@@ -0,0 +1,45 @@
+/**
+ * \file dnn/src/cuda/check_has_inf/opr_impl.cpp
+ * MegEngine is Licensed under the Apache License, Version 2.0 (the "License")
+ *
+ * Copyright (c) 2014-2021 Megvii Inc. All rights reserved.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * ARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ */
+
+#include "src/cuda/check_has_inf/opr_impl.h"
+#include "src/cuda/reduce_helper.cuh"
+
+#include "src/cuda/handle.h"
+#include "src/cuda/utils.h"
+
+#include "src/common/reduce_helper.h"
+
+namespace megdnn {
+namespace cuda {
+
+using reduce::CheckHasInfOp;
+
+size_t CheckHasInfImpl::get_workspace_in_bytes(const TensorLayout& src,
+                                               const TensorLayout& dst) {
+    typedef CheckHasInfOp<dt_float32, dt_int32, dt_int32> Op;
+    return get_reduce_workspace_in_bytes<Op>(1, src.total_nr_elems(), 1);
+}
+
+void CheckHasInfImpl::exec(_megdnn_tensor_in src, _megdnn_tensor_out dst,
+                           _megdnn_workspace workspace) {
+    check_exec(src.layout, dst.layout, workspace.size);
+    typedef CheckHasInfOp<dt_float32, dt_int32, dt_int32> Op;
+    auto stream = cuda_stream(this->handle());
+    auto B = src.layout.total_nr_elems();
+    return run_reduce<Op, false>(
+            workspace.ptr<dt_int32>(), 1, B, 1, stream,
+            Op(src.ptr<dt_float32>(), dst.ptr<dt_int32>(), B));
+}
+
+}  // namespace cuda
+}  // namespace megdnn
+
+// vim: syntax=cpp.doxygen
diff --git a/dnn/src/cuda/check_has_inf/opr_impl.h b/dnn/src/cuda/check_has_inf/opr_impl.h
new file mode 100644
index 0000000000000000000000000000000000000000..32d60f66e428bb3b9ef589a35d596b2aba1deeed
--- /dev/null
+++ b/dnn/src/cuda/check_has_inf/opr_impl.h
@@ -0,0 +1,36 @@
+/**
+ * \file dnn/src/cuda/check_has_inf/opr_impl.h
+ * MegEngine is Licensed under the Apache License, Version 2.0 (the "License")
+ *
+ * Copyright (c) 2014-2021 Megvii Inc. All rights reserved.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * ARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ */
+
+#pragma once
+
+#include "megdnn/oprs/utils.h"
+#include "src/cuda/utils.h"
+
+namespace megdnn {
+namespace cuda {
+
+class CheckHasInfImpl final : public CheckHasInf {
+public:
+    using CheckHasInf::CheckHasInf;
+
+    size_t get_workspace_in_bytes(const TensorLayout& src,
+                                  const TensorLayout& dst) override;
+
+    bool is_thread_safe() const override { return true; }
+
+    void exec(_megdnn_tensor_in src, _megdnn_tensor_out dst,
+              _megdnn_workspace workspace) override;
+};
+
+}  // namespace cuda
+}  // namespace megdnn
+
+// vim: syntax=cpp.doxygen
diff --git a/dnn/src/cuda/handle_create.cpp b/dnn/src/cuda/handle_create.cpp
index 80ac59638c7fdc0be3288033341165ebacd6a0f8..afbd1dee63729531a041b436bc38feee86ef3e6b 100644
--- a/dnn/src/cuda/handle_create.cpp
+++ b/dnn/src/cuda/handle_create.cpp
@@ -17,6 +17,7 @@
 #include "src/cuda/argsort/opr_impl.h"
 #include "src/cuda/batch_normalization/opr_impl.h"
 #include "src/cuda/batched_matrix_mul/opr_impl.h"
+#include "src/cuda/check_has_inf/opr_impl.h"
 #include "src/cuda/checksum/opr_impl.h"
 #include "src/cuda/concat/opr_impl.h"
 #include "src/cuda/cond_take/opr_impl.h"
diff --git a/dnn/src/cuda/reduce/reduce.cu b/dnn/src/cuda/reduce/reduce.cu
index 992513cb14483fa4d514cfc9bc24b3e7933f1c01..5f6ab475a307792b1045bc064ee0bd6d2e865824 100644
--- a/dnn/src/cuda/reduce/reduce.cu
+++ b/dnn/src/cuda/reduce/reduce.cu
@@ -18,15 +18,15 @@ namespace cuda {
 
 using namespace reduce;
 
-#define COMMOA ,
+#define COMMA ,
 
 #define INST(sctype, dctype, wtype)                                  \
-    INST_REDUCE(SumOp<sctype COMMOA dctype COMMOA wtype>, false);    \
-    INST_REDUCE(SumSqrOp<sctype COMMOA dctype COMMOA wtype>, false); \
-    INST_REDUCE(ProdOp<sctype COMMOA dctype COMMOA wtype>, false);   \
-    INST_REDUCE(MinOp<sctype COMMOA dctype COMMOA wtype>, false);    \
-    INST_REDUCE(MaxOp<sctype COMMOA dctype COMMOA wtype>, false);    \
-    INST_REDUCE(MeanOp<sctype COMMOA dctype COMMOA wtype>, false);
+    INST_REDUCE(SumOp<sctype COMMA dctype COMMA wtype>, false);    \
+    INST_REDUCE(SumSqrOp<sctype COMMA dctype COMMA wtype>, false); \
+    INST_REDUCE(ProdOp<sctype COMMA dctype COMMA wtype>, false);   \
+    INST_REDUCE(MinOp<sctype COMMA dctype COMMA wtype>, false);    \
+    INST_REDUCE(MaxOp<sctype COMMA dctype COMMA wtype>, false);    \
+    INST_REDUCE(MeanOp<sctype COMMA dctype COMMA wtype>, false);
 
 #define cb(_dt) \
     INST(DTypeTrait<_dt>::ctype, DTypeTrait<_dt>::ctype, DTypeTrait<_dt>::ctype)
@@ -40,6 +40,7 @@ INST(int, float, float)
 
 #undef cb
 #undef INST
+#undef COMMA
 
 }  // namespace cuda
 }  // namespace megdnn
diff --git a/dnn/src/naive/check_has_inf/opr_impl.cpp b/dnn/src/naive/check_has_inf/opr_impl.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..1a30910c981f451f5a92e65634362c0f7fd0ae83
--- /dev/null
+++ b/dnn/src/naive/check_has_inf/opr_impl.cpp
@@ -0,0 +1,59 @@
+/**
+ * \file dnn/src/naive/check_has_inf/opr_impl.cpp
+ * MegEngine is Licensed under the Apache License, Version 2.0 (the "License")
+ *
+ * Copyright (c) 2014-2021 Megvii Inc. All rights reserved.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * ARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ */
+
+#include "src/naive/check_has_inf/opr_impl.h"
+
+#include "src/common/utils.h"
+#include "src/naive/handle.h"
+
+namespace {
+using namespace megdnn;
+
+#define src_ctype dt_float32
+#define wtype dt_int32
+
+void reduce_fwd(const src_ctype* sptr, wtype* dptr, size_t size) {
+    std::function<wtype(size_t, size_t)> func;
+    func = [&](size_t l, size_t r) -> wtype {
+        if (l + 1 < r) {
+            size_t mid = l + (r - l) / 2;
+            return func(l, mid) | func(mid, r);
+        } else {
+            return static_cast<wtype>(std::isinf(sptr[l]));
+        }
+    };
+
+    dptr[0] = func(0, size);
+}
+
+}  // namespace
+
+namespace megdnn {
+namespace naive {
+
+size_t CheckHasInfImpl::get_workspace_in_bytes(const TensorLayout&,
+                                               const TensorLayout&) {
+    return 0;
+}
+
+void CheckHasInfImpl::exec(_megdnn_tensor_in src, _megdnn_tensor_out dst,
+                           _megdnn_workspace workspace) {
+    check_exec(src.layout, dst.layout, workspace.size);
+
+    auto handle = static_cast<HandleImpl*>(this->handle());
+    MEGDNN_DISPATCH_CPU_KERN(
+            handle, reduce_fwd(src.ptr<dt_float32>(), dst.ptr<dt_int32>(),
+                               src.layout.total_nr_elems()));
+}
+}  // namespace naive
+}  // namespace megdnn
+
+// vim: syntax=cpp.doxygen
diff --git a/dnn/src/naive/check_has_inf/opr_impl.h b/dnn/src/naive/check_has_inf/opr_impl.h
new file mode 100644
index 0000000000000000000000000000000000000000..53e9c6351c5aac09ea3c7e96152f563adb4f1677
--- /dev/null
+++ b/dnn/src/naive/check_has_inf/opr_impl.h
@@ -0,0 +1,35 @@
+/**
+ * \file dnn/src/naive/check_has_inf/opr_impl.h
+ * MegEngine is Licensed under the Apache License, Version 2.0 (the "License")
+ *
+ * Copyright (c) 2014-2021 Megvii Inc. All rights reserved.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * ARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ */
+
+#pragma once
+
+#include "megdnn/oprs.h"
+
+namespace megdnn {
+namespace naive {
+
+class CheckHasInfImpl final : public CheckHasInf {
+public:
+    using CheckHasInf::CheckHasInf;
+
+    bool is_thread_safe() const override { return true; }
+
+    size_t get_workspace_in_bytes(const TensorLayout& src,
+                                  const TensorLayout& dst) override;
+
+    void exec(_megdnn_tensor_in src, _megdnn_tensor_out dst,
+              _megdnn_workspace workspace) override;
+};
+
+}  // namespace naive
+}  // namespace megdnn
+
+// vim: syntax=cpp.doxygen
diff --git a/dnn/src/naive/handle.cpp b/dnn/src/naive/handle.cpp
index e6138c4aeda61458fe63575447c349250a08932e..7cb31fb06935a497235508af7606952c36131db7 100644
--- a/dnn/src/naive/handle.cpp
+++ b/dnn/src/naive/handle.cpp
@@ -21,6 +21,7 @@
 #include "src/naive/batch_conv_bias/opr_impl.h"
 #include "src/naive/batch_normalization/opr_impl.h"
 #include "src/naive/batched_matrix_mul/opr_impl.h"
+#include "src/naive/check_has_inf/opr_impl.h"
 #include "src/naive/checksum/opr_impl.h"
 #include "src/naive/concat/opr_impl.h"
 #include "src/naive/cond_take/opr_impl.h"
diff --git a/dnn/src/rocm/reduce/reduce.cpp.hip b/dnn/src/rocm/reduce/reduce.cpp.hip
index 88dfa632675a362784365418e6af641ef4834063..6a3eb72722e1140d7491ebda574adaef9e6ccc22 100644
--- a/dnn/src/rocm/reduce/reduce.cpp.hip
+++ b/dnn/src/rocm/reduce/reduce.cpp.hip
@@ -18,15 +18,15 @@ namespace rocm {
 
 using namespace reduce;
 
-#define COMMOA ,
+#define COMMA ,
 
 #define INST(sctype, dctype, wtype)                                  \
-    INST_REDUCE(SumOp<sctype COMMOA dctype COMMOA wtype>, false);    \
-    INST_REDUCE(SumSqrOp<sctype COMMOA dctype COMMOA wtype>, false); \
-    INST_REDUCE(ProdOp<sctype COMMOA dctype COMMOA wtype>, false);   \
-    INST_REDUCE(MinOp<sctype COMMOA dctype COMMOA wtype>, false);    \
-    INST_REDUCE(MaxOp<sctype COMMOA dctype COMMOA wtype>, false);    \
-    INST_REDUCE(MeanOp<sctype COMMOA dctype COMMOA wtype>, false);
+    INST_REDUCE(SumOp<sctype COMMA dctype COMMA wtype>, false);    \
+    INST_REDUCE(SumSqrOp<sctype COMMA dctype COMMA wtype>, false); \
+    INST_REDUCE(ProdOp<sctype COMMA dctype COMMA wtype>, false);   \
+    INST_REDUCE(MinOp<sctype COMMA dctype COMMA wtype>, false);    \
+    INST_REDUCE(MaxOp<sctype COMMA dctype COMMA wtype>, false);    \
+    INST_REDUCE(MeanOp<sctype COMMA dctype COMMA wtype>, false);
 
 #define cb(_dt) \
     INST(DTypeTrait<_dt>::ctype, DTypeTrait<_dt>::ctype, DTypeTrait<_dt>::ctype)
@@ -39,6 +39,7 @@ INST(float, dt_float16, float)
 INST(int, float, float)
 #undef cb
 #undef INST
+#undef COMMA
 
 }  // namespace rocm
 }  // namespace megdnn
diff --git a/dnn/test/common/checker.cpp b/dnn/test/common/checker.cpp
index 8c5bbf90ad93886edb11875e3b1b106cc467fcc5..656175e5e1b32aa0ffae12f72e9ac42fffa22be3 100644
--- a/dnn/test/common/checker.cpp
+++ b/dnn/test/common/checker.cpp
@@ -23,7 +23,7 @@ namespace {
     ::testing::AssertionResult assert_tensor_eq_with_iter(
             const char *expr0, const char *expr1,
             Iter it0, Iter it1, const TensorLayout &layout,
-            float maxerr, float maxerr_avg, float maxerr_avg_biased) {
+            float maxerr, float maxerr_avg, float maxerr_avg_biased, bool allow_invalid) {
 
         auto nr_elem = layout.total_nr_elems();
         double error_sum = 0;
@@ -33,8 +33,8 @@ namespace {
             float err = diff(iv0, iv1);
             error_sum += std::abs(err);
             error_sum_biased += err;
-            if (!good_float(iv0) || !good_float(iv1) ||
-                std::abs(err) > maxerr) {
+            if (!allow_invalid && (!good_float(iv0) || !good_float(iv1) ||
+                        std::abs(err) > maxerr)) {
                 Index index(layout, i);
                 return ::testing::AssertionFailure()
                        << "Unequal value\n"
@@ -82,14 +82,14 @@ namespace {
     ::testing::AssertionResult assert_tensor_eq_with_dtype(
             const char *expr0, const char *expr1,
             const TensorND &v0, const TensorND &v1,
-            float maxerr, float maxerr_avg, float maxerr_avg_biased) {
+            float maxerr, float maxerr_avg, float maxerr_avg_biased, bool allow_invalid) {
         if (!std::is_same<ctype, dt_qint4>::value &&
             !std::is_same<ctype, dt_quint4>::value) {
             if (v0.layout.is_physical_contiguous() &&
                 v1.layout.is_physical_contiguous()) {
                 return assert_tensor_eq_with_iter<ctype>(
                         expr0, expr1, v0.ptr<ctype>(), v1.ptr<ctype>(),
-                        v0.layout, maxerr, maxerr_avg, maxerr_avg_biased);
+                        v0.layout, maxerr, maxerr_avg, maxerr_avg_biased, allow_invalid);
             }
         }
 
@@ -98,7 +98,7 @@ namespace {
 
         return assert_tensor_eq_with_iter<ctype>(expr0, expr1, it0, it1,
                                                  v0.layout, maxerr, maxerr_avg,
-                                                 maxerr_avg_biased);
+                                                 maxerr_avg_biased, allow_invalid);
     }
 
     template<class Impl>
@@ -136,7 +136,7 @@ namespace {
         const char* /*expr_maxerr_avg*/,
         const char* /*expr_maxerr_avg*/,
         const TensorND &v0, const TensorND &v1,
-        float maxerr, float maxerr_avg, float maxerr_avg_biased) {
+        float maxerr, float maxerr_avg, float maxerr_avg_biased, bool allow_invalid) {
 
     if (!v0.layout.eq_shape(v1.layout)) {
         return ::testing::AssertionFailure()
@@ -160,7 +160,7 @@ namespace {
 #define cb(_dt)                                                     \
     case DTypeTrait<_dt>::enumv:                                    \
         return assert_tensor_eq_with_dtype<DTypeTrait<_dt>::ctype>( \
-                expr0, expr1, v0, v1, maxerr, maxerr_avg, maxerr_avg_biased);
+                expr0, expr1, v0, v1, maxerr, maxerr_avg, maxerr_avg_biased, allow_invalid);
         MEGDNN_FOREACH_COMPUTING_DTYPE(cb)
         MEGDNN_FOREACH_QUANTIZED_DTYPE(cb)
         //! In order to avoid an unnecessary increase in binary size, we just
@@ -174,6 +174,17 @@ namespace {
 
 }
 
+::testing::AssertionResult test::__assert_tensor_eq_allow_invalid(
+        const char* expr0, const char* expr1, const char* expr_maxerr,
+        const char* expr_maxerr_avg, const char* expr_maxerr_avg_biased,
+        const TensorND& v0, const TensorND& v1, float maxerr, float maxerr_avg,
+        float maxerr_avg_biased) {
+    return __assert_tensor_eq(expr0, expr1, expr_maxerr, expr_maxerr_avg,
+                              expr_maxerr_avg_biased, v0, v1, maxerr,
+                              maxerr_avg, maxerr_avg_biased, true);
+};
+
+
 CheckerHelper::CheckerHelper(Handle *handle, bool check_dispatch):
     m_handle_cur(handle),
     m_default_rng(new NormalRNG())
@@ -411,9 +422,15 @@ void CheckerHelper::check_tensors(const TensorValueArray& expected,
     for (size_t i = 0; i < expected.size(); ++i) {
         if (expected[i].layout.ndim == 0)
             continue;
-        MEGDNN_ASSERT_TENSOR_EQ_EPS_AVG(expected[i], computed[i], m_epsilon,
-                                        m_max_avg_error,
-                                        m_max_avg_biased_error);
+        if (m_allow_invalid_check) {
+            MEGDNN_ASSERT_TENSOR_EQ_EPS_AVG_ALLOW_INVALID(
+                    expected[i], computed[i], m_epsilon, m_max_avg_error,
+                    m_max_avg_biased_error);
+        } else {
+            MEGDNN_ASSERT_TENSOR_EQ_EPS_AVG(expected[i], computed[i], m_epsilon,
+                                            m_max_avg_error,
+                                            m_max_avg_biased_error);
+        }
     }
 }
 
diff --git a/dnn/test/common/checker.h b/dnn/test/common/checker.h
index c00632f2939921a54e58b3f8ad95d1ad9fc9b79f..48337100360ae6d64894167589e93a78a847e7dd 100644
--- a/dnn/test/common/checker.h
+++ b/dnn/test/common/checker.h
@@ -79,6 +79,7 @@ protected:
     bool m_no_naive_and_check = false;
     bool m_stable_check = false;
     bool m_force_deduce_dst = true;
+    bool m_allow_invalid_check = false;
     /**
      * the offset from the start of malloc memory
      *
@@ -248,6 +249,11 @@ public:
         return *this;
     }
 
+    Checker& set_allow_invalid_check(bool allow_invalid_check) {
+        m_allow_invalid_check = allow_invalid_check;
+        return *this;
+    }
+
     //! load input tensors from file for next run
     Checker& load_input_tensors(const char* fpath) {
         m_input_tensors_fpath = fpath;
@@ -326,6 +332,12 @@ private:
 };
 
 ::testing::AssertionResult __assert_tensor_eq(
+        const char* expr0, const char* expr1, const char* expr_maxerr,
+        const char* expr_maxerr_avg, const char* expr_maxerr_avg_biased,
+        const TensorND& v0, const TensorND& v1, float maxerr, float maxerr_avg,
+        float maxerr_avg_biased, bool allow_invalid = false);
+
+::testing::AssertionResult __assert_tensor_eq_allow_invalid(
         const char* expr0, const char* expr1, const char* expr_maxerr,
         const char* expr_maxerr_avg, const char* expr_maxerr_avg_biased,
         const TensorND& v0, const TensorND& v1, float maxerr, float maxerr_avg,
@@ -336,6 +348,11 @@ private:
     ASSERT_PRED_FORMAT5(::megdnn::test::__assert_tensor_eq, v0, v1, maxerr, \
                         maxerr_avg, maxerr_avg_biased)
 
+#define MEGDNN_ASSERT_TENSOR_EQ_EPS_AVG_ALLOW_INVALID(                        \
+        v0, v1, maxerr, maxerr_avg, maxerr_avg_biased)                        \
+    ASSERT_PRED_FORMAT5(::megdnn::test::__assert_tensor_eq_allow_invalid, v0, \
+                        v1, maxerr, maxerr_avg, maxerr_avg_biased)
+
 #define MEGDNN_ASSERT_TENSOR_EQ_EPS(v0, v1, maxerr) \
     MEGDNN_ASSERT_TENSOR_EQ_EPS_AVG(v0, v1, maxerr, maxerr, maxerr)
 
@@ -435,7 +452,7 @@ TensorND TensorValue(const TensorShape& shape, T dtype,
 
 template <typename T, typename U>
 TensorND TensorValueLowbit4(const TensorShape& shape, T dtype,
-                                std::vector<U> values) {
+                            std::vector<U> values) {
     TensorND tensor;
     tensor.layout = {shape, dtype};
     tensor.raw_ptr =
diff --git a/dnn/test/common/exec_proxy.h b/dnn/test/common/exec_proxy.h
index 69ae544c8239fe52e2dc4ff58c15a5e5bf170fc2..1393f357d46b585152736dc5f76c5a627ef24bfc 100644
--- a/dnn/test/common/exec_proxy.h
+++ b/dnn/test/common/exec_proxy.h
@@ -38,6 +38,22 @@ struct ExecProxy<Opr, 8, true> {
     }
 };
 
+template <typename Opr>
+struct ExecProxy<Opr, 7, true> {
+    WorkspaceWrapper W;
+    void exec(Opr* opr, const TensorNDArray& tensors) {
+        if (!W.valid()) {
+            W = WorkspaceWrapper(opr->handle(), 0);
+        }
+        W.update(opr->get_workspace_in_bytes(
+                tensors[0].layout, tensors[1].layout, tensors[2].layout,
+                tensors[3].layout, tensors[4].layout, tensors[5].layout,
+                tensors[6].layout));
+        opr->exec(tensors[0], tensors[1], tensors[2], tensors[3], tensors[4],
+                  tensors[5], tensors[6], W.workspace());
+    }
+};
+
 template <typename Opr>
 struct ExecProxy<Opr, 6, true> {
     WorkspaceWrapper W;
@@ -149,24 +165,6 @@ struct ExecProxy<Opr, 2, false> {
     }
 };
 
-template <typename Opr>
-struct ExecProxy<Opr, 7, true> {
-    WorkspaceWrapper W;
-
-    void exec(Opr* opr, const TensorNDArray& tensors) {
-        if (!W.valid()) {
-            W = WorkspaceWrapper(opr->handle(), 0);
-        }
-        W.update(opr->get_workspace_in_bytes(
-                tensors[0].layout, tensors[1].layout, tensors[2].layout,
-                tensors[3].layout, tensors[4].layout, tensors[5].layout,
-                tensors[6].layout));
-
-        opr->exec(tensors[0], tensors[1], tensors[2], tensors[3], tensors[4],
-                  tensors[5], tensors[6], W.workspace());
-    }
-};
-
 }  // namespace test
 }  // namespace megdnn
 // vim: syntax=cpp.doxygen
diff --git a/dnn/test/common/rng.cpp b/dnn/test/common/rng.cpp
index 6e6e9fbf282409852ab115534d0e2a7e8c66fbba..70921a879aefa040d167757c799766d9aabfa18d 100644
--- a/dnn/test/common/rng.cpp
+++ b/dnn/test/common/rng.cpp
@@ -301,9 +301,8 @@ void UniformFloatNonZeroRNG::fill_fast_float32(dt_float32* dest, size_t size) {
     }
 }
 
-void UniformFloatWithZeroRNG::fill_fast_float32(dt_float32 *dest, size_t size) {
+void UniformFloatWithValueRNG::fill_fast_float32(dt_float32 *dest, size_t size) {
     RNGxorshf gen{RandomState::generator()};
-    printf("a %f, b %f \n", m_dist.a(), m_dist.b());
     auto k = double(m_dist.b() - m_dist.a()) /
         double(RNGxorshf::max() - RNGxorshf::min() + 1.0);
     auto b = m_dist.a() - RNGxorshf::min() * k;
@@ -312,9 +311,8 @@ void UniformFloatWithZeroRNG::fill_fast_float32(dt_float32 *dest, size_t size) {
     auto pb = 0.f - RNGxorshf::min() * p;
     for (size_t i = 0; i < size; ++ i) {
         float rnd = gen() * p + pb;
-        //printf("%.3f \n", rnd);
-        if(rnd < zero_val_proportion_) {
-            dest[i] = 0.f;
+        if(rnd < val_proportion_) {
+            dest[i] = val_;
         } else {
             dest[i] = gen() * k + b;
         }
diff --git a/dnn/test/common/rng.h b/dnn/test/common/rng.h
index 324a0518cf8c495438b729d144da4b28a9846649..6b0d2cc006d6f6f4f1a308a3096e25d7a1d1f97a 100644
--- a/dnn/test/common/rng.h
+++ b/dnn/test/common/rng.h
@@ -11,10 +11,10 @@
 #pragma once
 #include "megdnn/dtype.h"
 
-#include "test/common/utils.h"
-#include "test/common/random_state.h"
 #include <random>
 #include <set>
+#include "test/common/random_state.h"
+#include "test/common/utils.h"
 
 namespace megdnn {
 namespace test {
@@ -80,7 +80,8 @@ public:
     }
 
     void gen(const TensorND& tensor) override {
-        megdnn_assert(tensor.layout.dtype.enumv() == DTypeTrait<dt_bfloat16>::enumv);
+        megdnn_assert(tensor.layout.dtype.enumv() ==
+                      DTypeTrait<dt_bfloat16>::enumv);
         size_t nr_elems = tensor.layout.span().dist_elem();
         auto offset = tensor.layout.span().low_elem;
         for (size_t i = 0; i < nr_elems; ++i) {
@@ -185,24 +186,31 @@ public:
     void fill_fast_float32(dt_float32* dest, size_t size) override;
 };
 
-class UniformFloatWithZeroRNG final : public UniformFloatRNG {
+class UniformFloatWithValueRNG : public UniformFloatRNG {
 public:
-    UniformFloatWithZeroRNG(dt_float32 a, dt_float32 b,
-                            float zero_val_proportion)
-            : UniformFloatRNG(a, b) {
-        if (zero_val_proportion < 0.f)
-            zero_val_proportion_ = 0.f;
-        else if (zero_val_proportion > 1.f)
-            zero_val_proportion_ = 1.f;
+    UniformFloatWithValueRNG(dt_float32 a, dt_float32 b, float val_proportion,
+                             float val)
+            : UniformFloatRNG(a, b), val_(val) {
+        if (val_proportion < 0.f)
+            val_proportion_ = 0.f;
+        else if (val_proportion > 1.f)
+            val_proportion_ = 1.f;
         else
-            zero_val_proportion_ = zero_val_proportion;
+            val_proportion_ = val_proportion;
     }
 
 private:
-    float zero_val_proportion_;
+    float val_proportion_, val_;
     void fill_fast_float32(dt_float32* dest, size_t size) override;
 };
 
+class UniformFloatWithZeroRNG final : public UniformFloatWithValueRNG {
+public:
+    UniformFloatWithZeroRNG(dt_float32 a, dt_float32 b,
+                            float zero_val_proportion)
+            : UniformFloatWithValueRNG(a, b, zero_val_proportion, 0.f) {}
+};
+
 class BernoulliRNG final : public IIDRNG {
 public:
     BernoulliRNG(dt_float32 probability_);
diff --git a/dnn/test/cuda/check_has_inf.cpp b/dnn/test/cuda/check_has_inf.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..1e452514579ffe9e098898ee703eeeb5895b8673
--- /dev/null
+++ b/dnn/test/cuda/check_has_inf.cpp
@@ -0,0 +1,33 @@
+/**
+ * \file dnn/test/cuda/check_has_inf.cpp
+ * MegEngine is Licensed under the Apache License, Version 2.0 (the "License")
+ *
+ * Copyright (c) 2014-2021 Megvii Inc. All rights reserved.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * ARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ */
+#include "megdnn/oprs.h"
+#include "test/common/checker.h"
+#include "test/cuda/fixture.h"
+
+namespace megdnn {
+namespace test {
+
+TEST_F(CUDA, CHECK_HAS_INF_BASIC) {
+    Checker<CheckHasInf> checker(handle_cuda());
+    checker.set_allow_invalid_check(true);
+    const auto inf = std::numeric_limits<float>::infinity();
+    UniformFloatWithValueRNG rng(-1.0f, 1.0f, 0.1f, inf);
+    checker.set_rng(0, &rng);
+    checker.execs({{512*16}, {1}});
+    rng = UniformFloatWithValueRNG(-1.0f, 1.0f, 1.f, inf);
+    checker.set_rng(0, &rng);
+    checker.execs({{512*16}, {1}});
+}
+
+}  // namespace test
+}  // namespace megdnn
+
+// vim: syntax=cpp.doxygen foldmethod=marker foldmarker=f{{{,f}}}
diff --git a/dnn/test/naive/check_has_inf.cpp b/dnn/test/naive/check_has_inf.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..1532a7c3c10ce9080b1697731baf000a452366ff
--- /dev/null
+++ b/dnn/test/naive/check_has_inf.cpp
@@ -0,0 +1,37 @@
+/**
+ * \file test/naive/check_has_inf.cpp
+ * MegEngine is Licensed under the Apache License, Version 2.0 (the "License")
+ *
+ * Copyright (c) 2014-2021 Megvii Inc. All rights reserved.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * ARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ */
+
+#include "test/naive/fixture.h"
+
+#include "megdnn/oprs.h"
+#include "test/common/checker.h"
+
+namespace megdnn {
+namespace test {
+
+TEST_F(NAIVE, CHECK_HAS_INF_BASIC) {
+    Checker<CheckHasInf> checker(handle(), false);
+    checker.exect(Testcase{TensorValue({4}, dtype::Float32(),
+                                       {1.1, 2.2, 3.3, 4.3}),
+                           {}},
+                  Testcase{{}, TensorValue({1}, dtype::Int32(), {0})});
+    checker.exect(
+            Testcase{TensorValue({4}, dtype::Float32(),
+                                 {1.1f, 2.2f, 3.3f,
+                                  std::numeric_limits<float>::infinity()}),
+                     {}},
+            Testcase{{}, TensorValue({1}, dtype::Int32(), {1})});
+}
+
+}  // namespace test
+}  // namespace megdnn
+
+// vim: syntax=cpp.doxygen foldmethod=marker foldmarker=f{{{,f}}}
diff --git a/imperative/python/megengine/functional/math.py b/imperative/python/megengine/functional/math.py
index f2187b3fc1aabe05cba80bf30135b279730ba012..fbc021a6970a655177e8ff108109240417aa0564 100644
--- a/imperative/python/megengine/functional/math.py
+++ b/imperative/python/megengine/functional/math.py
@@ -959,3 +959,16 @@ def svd(inp: Tensor, full_matrices=False, compute_uv=True) -> Tensor:
     op = builtin.SVD(full_matrices=full_matrices, compute_uv=compute_uv)
     U, sigma, V = apply(op, inp)
     return U, sigma, V
+
+
+def _has_inf(inp: Tensor) -> Tensor:
+    """
+    Check whether input contains infinite value.
+
+    :param inp: a tensor to be checked.
+    :return: a int32 scalar tensor, 0 for False and 1 for True.
+    """
+    op = builtin.CheckHasInf()
+    (oup,) = apply(op, inp.reshape(-1).astype("float32"))
+    oup._setscalar()
+    return oup
diff --git a/imperative/python/test/unit/functional/test_math.py b/imperative/python/test/unit/functional/test_math.py
index 661e40d134ecf2d2d190d0cebaf099c1135c80b9..a14e8b54de7ae19d558d31a49c9638123110e4bb 100644
--- a/imperative/python/test/unit/functional/test_math.py
+++ b/imperative/python/test/unit/functional/test_math.py
@@ -157,3 +157,14 @@ def test_sum_neg_axis():
         np.testing.assert_allclose(get.numpy(), ref, rtol=1e-6)
     with pytest.raises(AssertionError):
         F.sum(tensor(data), axis=(-1, 1))
+
+
+def test_has_inf():
+    shape = (32, 3, 32, 32)
+    data = np.random.random(shape).astype(np.float32)
+    rst = F.math._has_inf(tensor(data))
+    np.testing.assert_equal(rst.numpy(), [0])
+
+    data[0][0][0][0] = float("inf")
+    rst = F.math._has_inf(tensor(data))
+    np.testing.assert_equal(rst.numpy(), [1])
diff --git a/imperative/src/impl/ops/misc.cpp b/imperative/src/impl/ops/misc.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..d08e09b801541d6813cd129eb82eadb978bdeaa3
--- /dev/null
+++ b/imperative/src/impl/ops/misc.cpp
@@ -0,0 +1,34 @@
+/**
+ * \file imperative/src/impl/ops/tensor_manip.cpp
+ * MegEngine is Licensed under the Apache License, Version 2.0 (the "License")
+ *
+ * Copyright (c) 2014-2021 Megvii Inc. All rights reserved.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * ARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ */
+#include "../op_trait.h"
+
+#include "megbrain/imperative/ops/autogen.h"
+#include "megbrain/opr/misc.h"
+
+namespace mgb {
+namespace imperative {
+
+namespace check_has_inf {
+auto apply_on_var_node(const OpDef& def, const VarNodeArray& inputs) {
+    auto&& op = def.cast_final_safe<CheckHasInf>();
+    mgb_assert(inputs.size() == 1);
+    OperatorNodeConfig config{op.make_name()};
+    return opr::CheckHasInf::make(inputs[0], {}, config);
+}
+OP_TRAIT_REG(CheckHasInf, CheckHasInf)
+        .apply_on_var_node(apply_on_var_node)
+        .fallback();
+}  // namespace check_has_inf
+
+}  // namespace imperative
+}  // namespace mgb
+
+// vim: syntax=cpp.doxygen foldmethod=marker foldmarker=f{{{,f}}}
diff --git a/src/core/include/megbrain/ir/ops.td b/src/core/include/megbrain/ir/ops.td
index 3a3fa7189526ee57628d210dd7b3260deeb7fe11..8da5647e896c2cf10bed5d849f816ebe191d03ed 100644
--- a/src/core/include/megbrain/ir/ops.td
+++ b/src/core/include/megbrain/ir/ops.td
@@ -307,4 +307,6 @@ def CambriconRuntime: MgbHashableOp<"CambriconRuntime"> {
 
 def CvtColor: MgbHashableOp<"CvtColor", [CvtColorParam]>;
 
+def CheckHasInf: MgbHashableOp<"CheckHasInf", [EmptyParam]>;
+
 #endif // MGB_OPS
diff --git a/src/opr/impl/misc.cpp b/src/opr/impl/misc.cpp
index 558ad0a229045378010fddbbaf2b8d1c5b4b4850..b8c1127848cc420fdc3f4305d9f4810a46015645 100644
--- a/src/opr/impl/misc.cpp
+++ b/src/opr/impl/misc.cpp
@@ -437,4 +437,19 @@ MGB_IMPL_OPR_GRAD(TopK) {
 }
 #endif
 
+/* ================= CheckHasInf =================  */
+namespace mgb {
+namespace opr {
+namespace intl {
+template<>
+struct MegDNNOprInitPostCtor<CheckHasInf> {
+    static void apply(cg::OperatorNodeBase &opr) {
+        opr.output(0)->dtype(dtype::Int32());
+    }
+};
+}
+}
+}
+MGB_DYN_TYPE_OBJ_FINAL_IMPL(CheckHasInf);
+MEGDNN_OPR_INIT1(CheckHasInf, "check_has_inf")
 // vim: syntax=cpp.doxygen foldmethod=marker foldmarker=f{{{,f}}}
diff --git a/src/opr/impl/misc.sereg.h b/src/opr/impl/misc.sereg.h
index 3e4c16e382ccbed114f0a11860f915465f72a2b3..15fc8aaea158bbcb66f0e3c83f87bad5746cfa1c 100644
--- a/src/opr/impl/misc.sereg.h
+++ b/src/opr/impl/misc.sereg.h
@@ -73,6 +73,7 @@ namespace opr {
 #if MGB_CUDA
     MGB_SEREG_OPR(NvOf, 1);
 #endif
+    MGB_SEREG_OPR(CheckHasInf, 1);
 
 } // namespace opr
 } // namespace mgb
diff --git a/src/opr/include/megbrain/opr/misc.h b/src/opr/include/megbrain/opr/misc.h
index f3559d953e321fd45ffb1fa3c3b15fcbe3c508a3..79c0a17712866d6847c6ed7f040b0a968c28282f 100644
--- a/src/opr/include/megbrain/opr/misc.h
+++ b/src/opr/include/megbrain/opr/misc.h
@@ -178,6 +178,8 @@ public:
                                          const OperatorNodeConfig& config = {});
 };
 
+MGB_DEFINE_MEGDNN_OPR_WRAPPER_FWD1(CheckHasInf);
+
 } // namespace opr
 } // namespace mgb