On Thu, Feb 25, 2021 at 11:53 AM Arnd Bergmann <arnd@xxxxxxxxxx> wrote:
>
> On Wed, Feb 24, 2021 at 10:37 PM Linus Torvalds
> <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > On Wed, Feb 24, 2021 at 1:30 PM Linus Torvalds
> > <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> > >
> > > Hmm. I haven't bisected things yet, but I suspect it's something with
> > > the KASAN patches. With this all applied, I get:
> > >
> > > lib/crypto/curve25519-hacl64.c: In function ‘ladder_cmult.constprop’:
> > > lib/crypto/curve25519-hacl64.c:601:1: warning: the frame size of
> > > 2288 bytes is larger than 2048 bytes [-Wframe-larger-than=]
> > >
> > > and
> > >
> > > lib/bitfield_kunit.c: In function ‘test_bitfields_constants’:
> > > lib/bitfield_kunit.c:93:1: warning: the frame size of 11200 bytes is
> > > larger than 2048 bytes [-Wframe-larger-than=]
> > >
> > > which is obviously not really acceptable. A 11kB stack frame _will_
> > > cause issues.
> >
> > A quick bisect shoes that this was introduced by "[patch 101/173]
> > kasan: remove redundant config option".
> >
> > I didn't check what part of that patch screws up, but it's definitely
> > doing something bad.
>
> I'm not sure why that patch surfaced the bug, but it's worth pointing
> out that the underlying problem is asan-stack in combination
> with the structleak plugin. This will happen for every user of kunit.
>
The patch didn't update KASAN_STACK dependency in kconfig:
config GCC_PLUGIN_STRUCTLEAK_BYREF
....
depends on !(KASAN && KASAN_STACK=1)
This 'depends on' stopped working with the patch
