Re: [dpdk-dev] [PATCH v13 1/4] enable ASan AddressSanitizer

["Peng, ZhihongX" <zhihongx.peng@intel.com>]

> -----Original Message-----
> From: David Marchand <david.marchand@redhat.com>
> Sent: Friday, October 29, 2021 5:22 PM
> To: Peng, ZhihongX <zhihongx.peng@intel.com>
> Cc: Thomas Monjalon <thomas@monjalon.net>; Burakov, Anatoly
> <anatoly.burakov@intel.com>; Ananyev, Konstantin
> <konstantin.ananyev@intel.com>; Stephen Hemminger
> <stephen@networkplumber.org>; Dumitrescu, Cristian
> <cristian.dumitrescu@intel.com>; Mcnamara, John
> <john.mcnamara@intel.com>; Richardson, Bruce
> <bruce.richardson@intel.com>; dev <dev@dpdk.org>; Lin, Xueqin
> <xueqin.lin@intel.com>
> Subject: Re: [PATCH v13 1/4] enable ASan AddressSanitizer
> 
> Replying on this patch since there is no cover letter.
> 
> This series looks acceptable to me for rc2.
> 
> Patch 3 and 4 will be merged first, since they fix issues that would be hit with
> ASan enabled.
> 
> I have comments mainly on rewording in commitlogs and documentation.
> 
> If you are fine with those comments, I'll fix them before pushing this series.

Thank you very much for your help, I agree with this modification, it's good.
You have done a lot of work for asan patch, thank you again.

Regards,
Peng,Zhihong
> 
> 
> On Wed, Oct 20, 2021 at 9:47 AM <zhihongx.peng@intel.com> wrote:
> >
> > From: Zhihong Peng <zhihongx.peng@intel.com>
> >
> > `AddressSanitizer
> > <https://github.com/google/sanitizers/wiki/AddressSanitizer>`_ (ASan)
> > is a widely-used debugging tool to detect memory access errors.
> > It helps to detect issues like use-after-free, various kinds of buffer
> > overruns in C/C++ programs, and other similar errors, as well as
> > printing out detailed debug information whenever an error is detected.
> >
> > We can enable ASan by adding below compilation options:
> > -Dbuildtype=debug -Db_lundef=false -Db_sanitize=address
> > "-Dbuildtype=debug": This is a non-essential option. When this option
> > is added, if a memory error occurs, ASan can clearly show where the
> > code is wrong.
> > "-Db_lundef=false": When use clang to compile DPDK, this option must
> > be added.
> >
> > Signed-off-by: Xueqin Lin <xueqin.lin@intel.com>
> > Signed-off-by: Zhihong Peng <zhihongx.peng@intel.com>
> > Acked-by: John McNamara <john.mcnamara@intel.com>
> 
> This patch affects the build process so it should be reflected in the patch title.
> I find the commitlog hard to read.
> 
> 
> Suggesting following rewording:
> """
> build: enable AddressSanitizer
> 
> AddressSanitizer [1] a.k.a. ASan is a widely-used debugging tool to detect
> memory access errors.
> It helps to detect issues like use-after-free, various kinds of buffer overruns
> in C/C++ programs, and other similar errors, as well as printing out detailed
> debug information whenever an error is detected.
> 
> ASan is integrated with gcc and clang and can be enabled via a meson
> option: -Db_sanitize=address
> See the documentation for details (especially regarding clang).
> 
> Enabling ASan has an impact on performance since additional checks are
> added to generated binaries.
> 
> Enabling ASan with Windows is currently not supported in DPDK.
> 
> 
> 1: https://github.com/google/sanitizers/wiki/AddressSanitizer
> """
> 
> > ---
> > v7: 1) Split doc and code into two.
> >     2) Modify asan.rst doc
> > v8: No change.
> > v9: 1) Add the check of libasan library.
> >     2) Add release notes.
> > v10:1) Split doc and code into two.
> >     2) Meson supports asan.
> > v11:Modify the document.
> > v12:No change.
> > v13:Modify the document.
> > ---
> >  config/meson.build                     | 16 ++++++++++++++
> >  devtools/words-case.txt                |  1 +
> >  doc/guides/prog_guide/asan.rst         | 30 ++++++++++++++++++++++++++
> >  doc/guides/prog_guide/index.rst        |  1 +
> >  doc/guides/rel_notes/release_21_11.rst |  9 ++++++++
> >  5 files changed, 57 insertions(+)
> >  create mode 100644 doc/guides/prog_guide/asan.rst
> >
> > diff --git a/config/meson.build b/config/meson.build index
> > 4cdf589e20..f02b0e9c6d 100644
> > --- a/config/meson.build
> > +++ b/config/meson.build
> > @@ -411,6 +411,22 @@ if get_option('b_lto')
> >      endif
> >  endif
> >
> > +if get_option('b_sanitize') == 'address' or get_option('b_sanitize') ==
> 'address,undefined'
> > +    if is_windows
> > +        error('ASan is not supported on windows')
> > +    endif
> 
> I see clang started supporting ASan for Windows in version 8.
> https://releases.llvm.org/8.0.0/tools/clang/docs/AddressSanitizer.html
> 
> I also found some blog about adding ASan support in MSVC.
> https://devblogs.microsoft.com/cppblog/addresssanitizer-asan-for-
> windows-with-msvc/
> 
> Keeping this limitation is acceptable for now, but I added a mention in
> commitlog.
> 
> 
> > +
> > +    if cc.get_id() == 'gcc'
> > +        asan_dep = cc.find_library('asan', required: true)
> > +        if (not cc.links('int main(int argc, char *argv[]) { return 0; }',
> > +                dependencies: asan_dep))
> > +            error('broken dependency, "libasan"')
> > +        endif
> > +        add_project_link_arguments('-lasan', language: 'c')
> > +        dpdk_extra_ldflags += '-lasan'
> > +    endif
> > +endif
> > +
> >  if get_option('default_library') == 'both'
> >      error( '''
> >   Unsupported value "both" for "default_library" option.
> > diff --git a/devtools/words-case.txt b/devtools/words-case.txt index
> > 0bbad48626..ada6910fa0 100644
> > --- a/devtools/words-case.txt
> > +++ b/devtools/words-case.txt
> > @@ -5,6 +5,7 @@ API
> >  Arm
> >  armv7
> >  armv8
> > +ASan
> >  BAR
> >  CRC
> >  DCB
> > diff --git a/doc/guides/prog_guide/asan.rst
> > b/doc/guides/prog_guide/asan.rst new file mode 100644 index
> > 0000000000..6888fc9a87
> > --- /dev/null
> > +++ b/doc/guides/prog_guide/asan.rst
> > @@ -0,0 +1,30 @@
> > +.. SPDX-License-Identifier: BSD-3-Clause
> > +   Copyright(c) 2021 Intel Corporation
> > +
> > +Running AddressSanitizer
> > +========================
> > +
> > +`AddressSanitizer
> > +<https://github.com/google/sanitizers/wiki/AddressSanitizer>`_ (ASan)
> > +is a widely-used debugging tool to detect memory access errors.
> > +It helps to detect issues like use-after-free, various kinds of
> > +buffer overruns in C/C++ programs, and other similar errors, as well
> > +as printing out detailed debug information whenever an error is detected.
> > +
> > +AddressSanitizer is a part of LLVM (3.1+) and GCC (4.8+).
> > +
> > +Add following meson build commands to enable ASan in the meson build
> system:
> > +
> > +* gcc::
> > +
> > +    -Dbuildtype=debug -Db_sanitize=address
> > +
> > +* clang::
> > +
> > +    -Dbuildtype=debug -Db_lundef=false -Db_sanitize=address
> 
> Suggests adding some explanations here and replacing like:
> 
> """
> ...
> 
> AddressSanitizer is a part of LLVM (3.1+) and GCC (4.8+).
> 
> Enabling ASan is done by passing the -Db_sanitize=address option to the
> meson build system, see :ref:`linux_gsg_compiling_dpdk` for details.
> 
> The way ASan is integrated with clang requires to allow undefined symbols
> when linking code.
> To do this, the -Db_lundef=false option must be added.
> 
> Additionally, passing -Dbuildtype=debug option might help getting more
> readable ASan reports.
> 
> Example::
> 
>   - gcc: meson setup -Db_sanitize=address <build_dir>
>   - clang: meson setup -Db_sanitize=address -Db_lundef=false <build_dir> """
> 
> > +
> > +.. Note::
> > +
> > +    a) If compile with gcc in centos, libasan needs to be installed separately.
> > +    b) If the program is tested using cmdline, you may need to execute the
> > +       "stty echo" command when an error occurs.
> 
> """
>   - The libasan package must be installed when compiling with gcc in
> Centos/RHEL.
>   - If the program is tested using cmdline, you may need to execute the
>     "stty echo" command when an error occurs.
> """
> 
> > diff --git a/doc/guides/prog_guide/index.rst
> > b/doc/guides/prog_guide/index.rst index 89af28dacb..b95c460b19 100644
> > --- a/doc/guides/prog_guide/index.rst
> > +++ b/doc/guides/prog_guide/index.rst
> > @@ -71,4 +71,5 @@ Programmer's Guide
> >      writing_efficient_code
> >      lto
> >      profile_app
> > +    asan
> >      glossary
> > diff --git a/doc/guides/rel_notes/release_21_11.rst
> > b/doc/guides/rel_notes/release_21_11.rst
> > index 3362c52a73..10f4275b1b 100644
> > --- a/doc/guides/rel_notes/release_21_11.rst
> > +++ b/doc/guides/rel_notes/release_21_11.rst
> > @@ -173,6 +173,15 @@ New Features
> >    * Added tests to verify tunnel header verification in IPsec inbound.
> >    * Added tests to verify inner checksum.
> >
> > +* **Enable ASan AddressSanitizer.**
> 
> Should be in past form:
> 
> * **Added ASan support.**
> 
> 
> 
> 
> 
> > +
> > +  `AddressSanitizer
> > +  <https://github.com/google/sanitizers/wiki/AddressSanitizer>`_
> > + (ASan)  is a widely-used debugging tool to detect memory access errors.
> > +  It helps to detect issues like use-after-free, various kinds of
> > + buffer  overruns in C/C++ programs, and other similar errors, as
> > + well as  printing out detailed debug information whenever an error is
> detected.
> 
> 
> --
> David Marchand