diff mbox series

[v1,6/6] bitfield: build kunit tests without structleak plugin

Message ID 20210917061104.2680133-7-brendanhiggins@google.com (mailing list archive)
State New
Headers show
Series kunit: build kunit tests without structleak plugin | expand

Commit Message

Brendan Higgins Sept. 17, 2021, 6:11 a.m. UTC
From: Arnd Bergmann <arnd@arndb.de>

The structleak plugin causes the stack frame size to grow immensely:

lib/bitfield_kunit.c: In function 'test_bitfields_constants':
lib/bitfield_kunit.c:93:1: error: the frame size of 7440 bytes is larger than 2048 bytes [-Werror=frame-larger-than=]

Turn it off in this file.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
---
 lib/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Arnd Bergmann Sept. 17, 2021, 7:22 a.m. UTC | #1
On Fri, Sep 17, 2021 at 8:11 AM Brendan Higgins
<brendanhiggins@google.com> wrote:
>
> From: Arnd Bergmann <arnd@arndb.de>
>
> The structleak plugin causes the stack frame size to grow immensely:
>
> lib/bitfield_kunit.c: In function 'test_bitfields_constants':
> lib/bitfield_kunit.c:93:1: error: the frame size of 7440 bytes is larger than 2048 bytes [-Werror=frame-larger-than=]
>
> Turn it off in this file.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
> ---
>  lib/Makefile | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/lib/Makefile b/lib/Makefile
> index 5efd1b435a37c..c93c4b59af969 100644
> --- a/lib/Makefile
> +++ b/lib/Makefile
> @@ -351,7 +351,7 @@ obj-$(CONFIG_OBJAGG) += objagg.o
>  obj-$(CONFIG_PLDMFW) += pldmfw/
>
>  # KUnit tests
> -CFLAGS_bitfield_kunit.o := $(call cc-option,-Wframe-larger-than=10240)
> +CFLAGS_bitfield_kunit.o := $(call cc-option,-Wframe-larger-than=10240) $(DISABLE_STRUCTLEAK_PLUGIN)

I think the  $(call cc-option,-Wframe-larger-than=10240) needs to be dropped
here. This was not in my original patch and it is definitely broken on
all architectures
with 8KB stack size or less if the function needs that much. What is the amount
of actual stack usage you observe without this? If we still get a warning, then
I think this needs to be fixed in the code.

       Arnd
Kees Cook Sept. 17, 2021, 3:57 p.m. UTC | #2
On Fri, Sep 17, 2021 at 09:22:08AM +0200, Arnd Bergmann wrote:
> On Fri, Sep 17, 2021 at 8:11 AM Brendan Higgins
> <brendanhiggins@google.com> wrote:
> >
> > From: Arnd Bergmann <arnd@arndb.de>
> >
> > The structleak plugin causes the stack frame size to grow immensely:
> >
> > lib/bitfield_kunit.c: In function 'test_bitfields_constants':
> > lib/bitfield_kunit.c:93:1: error: the frame size of 7440 bytes is larger than 2048 bytes [-Werror=frame-larger-than=]
> >
> > Turn it off in this file.
> >
> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> > Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
> > ---
> >  lib/Makefile | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/lib/Makefile b/lib/Makefile
> > index 5efd1b435a37c..c93c4b59af969 100644
> > --- a/lib/Makefile
> > +++ b/lib/Makefile
> > @@ -351,7 +351,7 @@ obj-$(CONFIG_OBJAGG) += objagg.o
> >  obj-$(CONFIG_PLDMFW) += pldmfw/
> >
> >  # KUnit tests
> > -CFLAGS_bitfield_kunit.o := $(call cc-option,-Wframe-larger-than=10240)
> > +CFLAGS_bitfield_kunit.o := $(call cc-option,-Wframe-larger-than=10240) $(DISABLE_STRUCTLEAK_PLUGIN)
> 
> I think the  $(call cc-option,-Wframe-larger-than=10240) needs to be dropped
> here. This was not in my original patch and it is definitely broken on
> all architectures
> with 8KB stack size or less if the function needs that much. What is the amount
> of actual stack usage you observe without this? If we still get a warning, then
> I think this needs to be fixed in the code.

With the frame-larger-than dropped:

Reviewed-by: Kees Cook <keescook@chromium.org>
Brendan Higgins Sept. 29, 2021, 9:04 p.m. UTC | #3
On Fri, Sep 17, 2021 at 12:22 AM Arnd Bergmann <arnd@arndb.de> wrote:
>
> On Fri, Sep 17, 2021 at 8:11 AM Brendan Higgins
> <brendanhiggins@google.com> wrote:
> >
> > From: Arnd Bergmann <arnd@arndb.de>
> >
> > The structleak plugin causes the stack frame size to grow immensely:
> >
> > lib/bitfield_kunit.c: In function 'test_bitfields_constants':
> > lib/bitfield_kunit.c:93:1: error: the frame size of 7440 bytes is larger than 2048 bytes [-Werror=frame-larger-than=]
> >
> > Turn it off in this file.
> >
> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> > Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
> > ---
> >  lib/Makefile | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/lib/Makefile b/lib/Makefile
> > index 5efd1b435a37c..c93c4b59af969 100644
> > --- a/lib/Makefile
> > +++ b/lib/Makefile
> > @@ -351,7 +351,7 @@ obj-$(CONFIG_OBJAGG) += objagg.o
> >  obj-$(CONFIG_PLDMFW) += pldmfw/
> >
> >  # KUnit tests
> > -CFLAGS_bitfield_kunit.o := $(call cc-option,-Wframe-larger-than=10240)
> > +CFLAGS_bitfield_kunit.o := $(call cc-option,-Wframe-larger-than=10240) $(DISABLE_STRUCTLEAK_PLUGIN)
>
> I think the  $(call cc-option,-Wframe-larger-than=10240) needs to be dropped
> here. This was not in my original patch and it is definitely broken on

Ah, someone else put that there, so I just left it, but I can drop it.

> all architectures
> with 8KB stack size or less if the function needs that much. What is the amount
> of actual stack usage you observe without this?

Well STRUCTLEAK claims 7440 bytes, but I don't entirely believe that.
Regardless, it is definitely less than 8KB.

> If we still get a warning, then
> I think this needs to be fixed in the code.
>
>        Arnd

Cheers
diff mbox series

Patch

diff --git a/lib/Makefile b/lib/Makefile
index 5efd1b435a37c..c93c4b59af969 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -351,7 +351,7 @@  obj-$(CONFIG_OBJAGG) += objagg.o
 obj-$(CONFIG_PLDMFW) += pldmfw/
 
 # KUnit tests
-CFLAGS_bitfield_kunit.o := $(call cc-option,-Wframe-larger-than=10240)
+CFLAGS_bitfield_kunit.o := $(call cc-option,-Wframe-larger-than=10240) $(DISABLE_STRUCTLEAK_PLUGIN)
 obj-$(CONFIG_BITFIELD_KUNIT) += bitfield_kunit.o
 obj-$(CONFIG_LIST_KUNIT_TEST) += list-test.o
 obj-$(CONFIG_LINEAR_RANGES_TEST) += test_linear_ranges.o