Re: lib/crypto/chacha.c:65:1: warning: the frame size of 1604 bytes is larger than 1024 bytes

[Herbert Xu]

On Thu, Aug 27, 2020 at 11:52:50AM +0800, kernel test robot wrote:
> 
> First bad commit (maybe != root cause):
> 
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   15bc20c6af4ceee97a1f90b43c0e386643c071b4
> commit: 5fb8ef25803ef33e2eb60b626435828b937bed75 crypto: chacha - move existing library code into lib/crypto
> date:   9 months ago
> config: i386-randconfig-r015-20200827 (attached as .config)
> compiler: gcc-9 (Debian 9.3.0-15) 9.3.0
> reproduce (this is a W=1 build):
>         git checkout 5fb8ef25803ef33e2eb60b626435828b937bed75
>         # save the attached .config to linux build tree
>         make W=1 ARCH=i386 
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> 
> All warnings (new ones prefixed by >>):
> 
>    lib/crypto/chacha.c: In function 'chacha_permute':
> >> lib/crypto/chacha.c:65:1: warning: the frame size of 1604 bytes is larger than 1024 bytes [-Wframe-larger-than=]
>       65 | }
>          | ^

This doesn't happen with a normal configuration.  To recreate
this warning, you need to enable both GCOV_KERNEL and UBSAN.

This is the minimal gcc command-line to recreate it:

gcc -Wframe-larger-than=1024 -fprofile-arcs -fsanitize=object-size -c -O2 chacha.c

If you take away either profile-arcs or sanitize=object-size then
the problem goes away.

Any suggestions?

Thanks,
-- 
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt