[compiler-rt] r369924 - [asan_symbolize] Avoid blocking when llvm-symbolizer is installed as addr2line

Tue Aug 27 12:45:03 PDT 2019

Hi Alexander, 

It looks like this commit is causing failures on Darwin: http://lab.llvm.org:8080/green/job/clang-stage1-RA/1421/consoleFull#15588960978254eaf0-7326-4999-85b0-388101f2d404 <http://lab.llvm.org:8080/green/job/clang-stage1-RA/1421/consoleFull#15588960978254eaf0-7326-4999-85b0-388101f2d404>

Can you please fix this?

Thanks,
Erik

> On Aug 26, 2019, at 9:22 AM, Alexander Richardson via llvm-commits <llvm-commits at lists.llvm.org> wrote:
> 
> Author: arichardson
> Date: Mon Aug 26 09:22:04 2019
> New Revision: 369924
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=369924&view=rev
> Log:
> [asan_symbolize] Avoid blocking when llvm-symbolizer is installed as addr2line
> 
> Summary:
> Currently, llvm-symbolizer will print -1 when presented with -1 and not
> print a second line. In that case we will block for ever trying to read
> the file name. This also happens for non-existent files, in which case GNU
> addr2line exits immediate, but llvm-symbolizer does not (see
> https://llvm.org/PR42754). While touching these lines, I also added some
> more debug logging to help diagnose this and potential future issues.
> 
> Reviewers: kcc, eugenis, glider, samsonov
> 
> Reviewed By: eugenis
> 
> Subscribers: kubamracek, #sanitizers, llvm-commits
> 
> Tags: #sanitizers, #llvm
> 
> Differential Revision: https://reviews.llvm.org/D65322
> 
> Modified:
>    compiler-rt/trunk/lib/asan/scripts/asan_symbolize.py
>    compiler-rt/trunk/test/asan/TestCases/Posix/asan-symbolize-bad-path.cpp
> 
> Modified: compiler-rt/trunk/lib/asan/scripts/asan_symbolize.py
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/scripts/asan_symbolize.py?rev=369924&r1=369923&r2=369924&view=diff
> ==============================================================================
> --- compiler-rt/trunk/lib/asan/scripts/asan_symbolize.py (original)
> +++ compiler-rt/trunk/lib/asan/scripts/asan_symbolize.py Mon Aug 26 09:22:04 2019
> @@ -27,6 +27,7 @@ import os
> import re
> import subprocess
> import sys
> +from distutils.spawn import find_executable
> 
> symbolizers = {}
> demangle = False
> @@ -153,6 +154,7 @@ class Addr2LineSymbolizer(Symbolizer):
>     addr2line_tool = 'addr2line'
>     if binutils_prefix:
>       addr2line_tool = binutils_prefix + addr2line_tool
> +    logging.debug('addr2line binary is %s' % find_executable(addr2line_tool))
>     cmd = [addr2line_tool, '-fi']
>     if demangle:
>       cmd += ['--demangle']
> @@ -174,14 +176,34 @@ class Addr2LineSymbolizer(Symbolizer):
>       is_first_frame = True
>       while True:
>         function_name = self.pipe.stdout.readline().rstrip()
> +        logging.debug("read function_name='%s' from addr2line" % function_name)
> +        # If llvm-symbolizer is installed as addr2line, older versions of
> +        # llvm-symbolizer will print -1 when presented with -1 and not print
> +        # a second line. In that case we will block for ever trying to read the
> +        # file name. This also happens for non-existent files, in which case GNU
> +        # addr2line exits immediate, but llvm-symbolizer does not (see
> +        # https://llvm.org/PR42754).
> +        if function_name == '-1':
> +          logging.debug("got function '-1' -> no more input")
> +          break
>         file_name = self.pipe.stdout.readline().rstrip()
> +        logging.debug("read file_name='%s' from addr2line" % file_name)
>         if is_first_frame:
>           is_first_frame = False
> -        elif function_name in ['', '??']:
> -          assert file_name == function_name
> +        elif function_name == '??':
> +          assert file_name == '??:0', file_name
> +          logging.debug("got function '??' -> no more input")
> +          break
> +        elif not function_name:
> +          assert not file_name, file_name
> +          logging.debug("got empty function name -> no more input")
>           break
>         lines.append((function_name, file_name));
> -    except Exception:
> +    except BrokenPipeError:
> +      logging.debug("got broken pipe, addr2line returncode=%d" % self.pipe.poll())
> +      lines.append(('??', '??:0'))
> +    except Exception as e:
> +      logging.debug("got unknown exception communicating with addr2line", exc_info=e)
>       lines.append(('??', '??:0'))
>     return ['%s in %s %s' % (addr, function, fix_filename(file)) for (function, file) in lines]
> 
> 
> Modified: compiler-rt/trunk/test/asan/TestCases/Posix/asan-symbolize-bad-path.cpp
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/asan/TestCases/Posix/asan-symbolize-bad-path.cpp?rev=369924&r1=369923&r2=369924&view=diff
> ==============================================================================
> --- compiler-rt/trunk/test/asan/TestCases/Posix/asan-symbolize-bad-path.cpp (original)
> +++ compiler-rt/trunk/test/asan/TestCases/Posix/asan-symbolize-bad-path.cpp Mon Aug 26 09:22:04 2019
> @@ -1,4 +1,15 @@
> // Test that asan_symbolize does not hang when provided with an non-existing
> // path.
> -// RUN: echo '#0 0xabcdabcd (%t/bad/path+0x1234)' | %asan_symbolize | FileCheck %s
> -// CHECK: #0 0xabcdabcd
> +// RUN: echo '#0 0xabcdabcd (%t/bad/path+0x1234)' | %asan_symbolize | FileCheck %s -check-prefix CHECK-BAD-FILE
> +// CHECK-BAD-FILE: #0 0xabcdabcd in ?? ??:0
> +// CHECK-BAD-FILE-EMPTY:
> +
> +// Also test that asan_symbolize doesn't assert on an invalid address with a valid file:
> +// RUN: %clangxx_asan -O0 %s -o %t
> +// RUN: echo '#0 0xabcdabcd (%t+0x0)' | %asan_symbolize | FileCheck %s -check-prefix CHECK-BAD-ADDR
> +// CHECK-BAD-ADDR: #0 0xabcdabcd in ??
> +// CHECK-BAD-ADDR-EMPTY:
> +
> +int main() {
> +  return 0;
> +}
> 
> 
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