2024-03-20 16:33:05

by Ian Rogers

Subject: [PATCH v1] perf build: Pretend scandirat is missing with msan

Memory sanitizer lacks an interceptor for scandirat, reporting all
memory it allocates as uninitialized. Memory sanitizer has a scandir
interceptor so use the fallback function in this case. This allows
perf test to run under memory sanitizer.

Signed-off-by: Ian Rogers <[email protected]>
---
tools/perf/Makefile.config | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index 1fe8df97fe88..74e0b17050b5 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -486,7 +486,10 @@ ifdef NO_DWARF
endif

ifeq ($(feature-scandirat), 1)
- CFLAGS += -DHAVE_SCANDIRAT_SUPPORT
+ # Ignore having scandirat with memory sanitizer that lacks an interceptor.
+ ifeq ($(filter s% -fsanitize=memory%,$(EXTRA_CFLAGS),),)
+ CFLAGS += -DHAVE_SCANDIRAT_SUPPORT
+ endif
endif

ifeq ($(feature-sched_getcpu), 1)
--
2.44.0.291.gc1ea87d7ee-goog

2024-03-20 16:36:46

by Ian Rogers

Subject: Re: [PATCH v1] perf build: Pretend scandirat is missing with msan

On Wed, Mar 20, 2024 at 9:32 AM Ian Rogers <[email protected]> wrote:
>
> Memory sanitizer lacks an interceptor for scandirat, reporting all
> memory it allocates as uninitialized. Memory sanitizer has a scandir
> interceptor so use the fallback function in this case. This allows
> perf test to run under memory sanitizer.
>
> Signed-off-by: Ian Rogers <[email protected]>

Note, as msan needs to instrument memory allocations libraries need to
be compiled with it. I lacked the msan built libraries and so built
with:
```
$ make -C tools/perf O=/tmp/perf DEBUG=1 EXTRA_CFLAGS="-O0 -g
-fno-omit-frame-pointer -fsanitize=memory
-fsanitize-memory-track-origins" CC=clang CXX=clang++ HOSTCC=clang
NO_LIBTRACEEVENT=1 NO_LIBELF=1 BUILD_BPF_SKEL=0 NO_LIBPFM=1
```
oh, I disabled libbpf here as the bpf system call also lacks msan interceptors.

Thanks,
Ian

> ---
> tools/perf/Makefile.config | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
> index 1fe8df97fe88..74e0b17050b5 100644
> --- a/tools/perf/Makefile.config
> +++ b/tools/perf/Makefile.config
> @@ -486,7 +486,10 @@ ifdef NO_DWARF
> endif
>
> ifeq ($(feature-scandirat), 1)
> - CFLAGS += -DHAVE_SCANDIRAT_SUPPORT
> + # Ignore having scandirat with memory sanitizer that lacks an interceptor.
> + ifeq ($(filter s% -fsanitize=memory%,$(EXTRA_CFLAGS),),)
> + CFLAGS += -DHAVE_SCANDIRAT_SUPPORT
> + endif
> endif
>
> ifeq ($(feature-sched_getcpu), 1)
> --
> 2.44.0.291.gc1ea87d7ee-goog
>

2024-04-25 18:46:08

by Arnaldo Carvalho de Melo

Subject: Re: [PATCH v1] perf build: Pretend scandirat is missing with msan

On Wed, Mar 20, 2024 at 09:32:44AM -0700, Ian Rogers wrote:
> Memory sanitizer lacks an interceptor for scandirat, reporting all
> memory it allocates as uninitialized. Memory sanitizer has a scandir
> interceptor so use the fallback function in this case. This allows
> perf test to run under memory sanitizer.

Thanks, applied to perf-tools-next,

- Arnaldo

> Signed-off-by: Ian Rogers <[email protected]>
> ---
> tools/perf/Makefile.config | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
> index 1fe8df97fe88..74e0b17050b5 100644
> --- a/tools/perf/Makefile.config
> +++ b/tools/perf/Makefile.config
> @@ -486,7 +486,10 @@ ifdef NO_DWARF
> endif
>
> ifeq ($(feature-scandirat), 1)
> - CFLAGS += -DHAVE_SCANDIRAT_SUPPORT
> + # Ignore having scandirat with memory sanitizer that lacks an interceptor.
> + ifeq ($(filter s% -fsanitize=memory%,$(EXTRA_CFLAGS),),)
> + CFLAGS += -DHAVE_SCANDIRAT_SUPPORT
> + endif
> endif
>
> ifeq ($(feature-sched_getcpu), 1)
> --
> 2.44.0.291.gc1ea87d7ee-goog

2024-04-25 18:48:06

by Arnaldo Carvalho de Melo

Subject: Re: [PATCH v1] perf build: Pretend scandirat is missing with msan

On Wed, Mar 20, 2024 at 09:36:19AM -0700, Ian Rogers wrote:
> On Wed, Mar 20, 2024 at 9:32 AM Ian Rogers <[email protected]> wrote:
> >
> > Memory sanitizer lacks an interceptor for scandirat, reporting all
> > memory it allocates as uninitialized. Memory sanitizer has a scandir
> > interceptor so use the fallback function in this case. This allows
> > perf test to run under memory sanitizer.
> >
> > Signed-off-by: Ian Rogers <[email protected]>
>
> Note, as msan needs to instrument memory allocations libraries need to
> be compiled with it. I lacked the msan built libraries and so built
> with:
> ```
> $ make -C tools/perf O=/tmp/perf DEBUG=1 EXTRA_CFLAGS="-O0 -g
> -fno-omit-frame-pointer -fsanitize=memory
> -fsanitize-memory-track-origins" CC=clang CXX=clang++ HOSTCC=clang
> NO_LIBTRACEEVENT=1 NO_LIBELF=1 BUILD_BPF_SKEL=0 NO_LIBPFM=1
> ```
> oh, I disabled libbpf here as the bpf system call also lacks msan interceptors.

I added the above notes to the cset message.

- Arnaldo

> Thanks,
> Ian
>
> > ---
> > tools/perf/Makefile.config | 5 ++++-
> > 1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
> > index 1fe8df97fe88..74e0b17050b5 100644
> > --- a/tools/perf/Makefile.config
> > +++ b/tools/perf/Makefile.config
> > @@ -486,7 +486,10 @@ ifdef NO_DWARF
> > endif
> >
> > ifeq ($(feature-scandirat), 1)
> > - CFLAGS += -DHAVE_SCANDIRAT_SUPPORT
> > + # Ignore having scandirat with memory sanitizer that lacks an interceptor.
> > + ifeq ($(filter s% -fsanitize=memory%,$(EXTRA_CFLAGS),),)
> > + CFLAGS += -DHAVE_SCANDIRAT_SUPPORT
> > + endif
> > endif
> >
> > ifeq ($(feature-sched_getcpu), 1)
> > --
> > 2.44.0.291.gc1ea87d7ee-goog
> >