[cfe-dev] Trouble supressing ASAN reported leaks

Dan Liew via cfe-dev cfe-dev at lists.llvm.org
Tue Dec 15 10:58:35 PST 2015


Hi,

I'm currently trying to find and fix memory leaks (compiling with
``-fsanitize=address``) in the KLEE tool [1] an having found some
leaks and I'm having trouble suppressing them.

I'm trying to suppress them using the
``-fsanitize-blacklist=blacklist.txt`` option as documented at
[2]. I'm using Clang 3.7 ( Arch Linux package 3.7.0-6).

The sort of reported leaks I see are

```
==9912==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 24 byte(s) in 1 object(s) allocated from:
    #0 0x4df4a0 in operator new(unsigned long)
(/home/dsl11/dev/klee/klee/build_asan/unittests/Expr/Release+Asserts/ExprTests+0x4df4a0)
    #1 0x4f76e1 in
klee::Array::CreateArray(std::__cxx11::basic_string<char,
std::char_traits<char>, std::allocator<char> > const&, unsigned long,
klee::ref<klee::ConstantExpr> const*, klee::ref<klee::ConstantExpr>
const*, unsigned int, unsigned int)
/home/dsl11/dev/klee/klee/src/lib/Expr/Expr.cpp:522:16
    #2 0x4e30d5 in (anonymous
namespace)::ExprTest_ConcatExtract_Test::TestBody()
/home/dsl11/dev/klee/klee/src/unittests/Expr/ExprTest.cpp:34:25
    #3 0x526410 in testing::Test::Run()
(/home/dsl11/dev/klee/klee/build_asan/unittests/Expr/Release+Asserts/ExprTests+0x526410)

...

Indirect leak of 80 byte(s) in 1 object(s) allocated from:
    #0 0x4df4a0 in operator new(unsigned long)
(/home/dsl11/dev/klee/klee/build_asan/unittests/Expr/Release+Asserts/ExprTests+0x4df4a0)
    #1 0x4f75ce in
klee::Array::CreateArray(std::__cxx11::basic_string<char,
std::char_traits<char>, std::allocator<char> > const&, unsigned long,
klee::ref<klee::ConstantExpr> const*, klee::ref<klee::ConstantExpr>
const*, unsigned int, u
nsigned int) /home/dsl11/dev/klee/klee/src/lib/Expr/Expr.cpp:506:25
    #2 0x4e2ff3 in (anonymous
namespace)::ExprTest_ConcatExtract_Test::TestBody()
/home/dsl11/dev/klee/klee/src/unittests/Expr/ExprTest.cpp:32:24
    #3 0x526410 in testing::Test::Run()
(/home/dsl11/dev/klee/klee/build_asan/unittests/Expr/Release+Asserts/ExprTests+0x526410)
```

The source of the trouble is this static object.

```
std::map<unsigned, std::vector<const Array *> *>
Array::symbolicArraySingletonMap;
```

Neither the ``std::vector<const Array*>`` pointers or the ``const
Array`` pointers are being freed. Sure this code is bad (don't blame
me, I didn't write it), but I want to skip over this leak to find more
interesting issues.

I can't seem to suppress it though. I've tried putting the following
in the ``blacklist.txt`` file

* Explicitly naming the source file, like this

src:/home/dsl11/dev/klee/klee/src/lib/Expr/Expr.cpp

* Naming the function where the leak originates (demangled)

fun:klee::Array::CreateArray

* Naming the function where the leak originates (mangled)

fun:_ZN4klee5Array11CreateArrayERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEmPKNS_3refINS_12ConstantExprEEESD_jj

* Naming the global (demangled)

global:klee::Array::symbolicArraySingletonMap

* Naming the global (mangled)

global:_ZN4klee5Array25symbolicArraySingletonMapE


None of these succeed in suppressing the error. Does anyone have any
idea what I'm doing wrong?

Note I'm also using a fairly new build of libstdc++ which is using a
new ABI [3]. I'm not sure if this would cause problems.

[1] https://github.com/klee/klee
[2] http://clang.llvm.org/docs/AddressSanitizer.html#suppressing-errors-in-recompiled-code-blacklist
[3] https://gcc.gnu.org/onlinedocs/libstdc++/manual/using_dual_abi.html

Thanks,
Dan.


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