From: Arnd Bergmann <arnd@arndb.de>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Ard Biesheuvel <ardb@kernel.org>,
kernel test robot <lkp@intel.com>,
Peter Oberparleiter <oberpar@linux.ibm.com>,
Kees Cook <keescook@chromium.org>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
kbuild-all@lists.01.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux Crypto Mailing List <linux-crypto@vger.kernel.org>
Subject: Re: lib/crypto/chacha.c:65:1: warning: the frame size of 1604 bytes is larger than 1024 bytes
Date: Thu, 27 Aug 2020 18:25:39 +0200 [thread overview]
Message-ID: <CAK8P3a3Wo2cj-tHybp_e0zJ2b-88V1oxZzBz-pKtMu-+DovF3w@mail.gmail.com> (raw)
In-Reply-To: <20200827115104.GA5409@gondor.apana.org.au>
On Thu, Aug 27, 2020 at 1:51 PM Herbert Xu <herbert@gondor.apana.org.au> wrote:
>
> On Thu, Aug 27, 2020 at 12:41:53PM +0200, Ard Biesheuvel wrote:
> >
> > That does not help, unfortunately.
> >
> > What does seem to work is
> >
> > struct chacha_state { u32 x[16]; };
> >
> > struct chacha_state chacha_permute(struct chacha_state st, int nrounds)
>
> Passing 64 bytes by value is not good.
>
> Passing struct chacha_state as a pointer doesn't work either.
Marking the function as __always_inline avoids the problem, as it
lets the compiler see the issue, but seems to produce somewhat
worse object code.
I also tested with clang-11, which supports both -fsanitize-bounds
and -fprofile-arcs but only needs 8 bytes of stack for this function.
One more data point, I looked at the actual object code and found
that neither -fprofile-arcs nor -fsanitize-bounds has a noticeable
impact on the object code output by themselves (aside of not
leading to the warning as you already mentioned). I would
conclude that there is an actual problem with gcc here.
Arnd
next prev parent reply other threads:[~2020-08-27 16:26 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-27 3:52 lib/crypto/chacha.c:65:1: warning: the frame size of 1604 bytes is larger than 1024 bytes kernel test robot
2020-08-27 8:05 ` Herbert Xu
2020-08-27 8:10 ` Ard Biesheuvel
2020-08-27 8:24 ` Herbert Xu
2020-08-27 17:34 ` Linus Torvalds
2020-08-27 17:55 ` Linus Torvalds
2020-08-27 18:42 ` Kees Cook
2020-08-27 19:02 ` Linus Torvalds
2020-08-27 19:32 ` Kees Cook
2020-08-27 19:11 ` Arnd Bergmann
2020-08-27 19:34 ` Kees Cook
2020-08-27 20:08 ` Linus Torvalds
2020-08-27 8:33 ` Arnd Bergmann
2020-08-27 8:42 ` Ard Biesheuvel
2020-08-27 9:19 ` Arnd Bergmann
2020-08-27 10:41 ` Ard Biesheuvel
2020-08-27 11:51 ` Herbert Xu
2020-08-27 16:25 ` Arnd Bergmann [this message]
2020-09-19 17:27 kernel test robot
2020-10-18 19:13 kernel test robot
2020-10-19 15:47 ` Joe Perches
2020-10-20 8:00 ` David Laight
2020-10-20 10:13 ` Joe Perches
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