Messages in this thread | | | From | Arnd Bergmann <> | Date | Mon, 17 Jun 2019 22:08:02 +0200 | Subject | Re: [PATCH] ima: dynamically allocate shash_desc |
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On Mon, Jun 17, 2019 at 8:08 PM Mimi Zohar <zohar@linux.ibm.com> wrote: > > On Mon, 2019-06-17 at 11:55 -0400, Mimi Zohar wrote: > > On Mon, 2019-06-17 at 13:20 +0200, Arnd Bergmann wrote: > > > On 32-bit ARM, we get a warning about excessive stack usage when > > > building with clang. > > > > > > security/integrity/ima/ima_crypto.c:504:5: error: stack frame size > > > of 1152 bytes in function 'ima_calc_field_array_hash' [-Werror,- > > > Wframe-larger-than=] > > > > I'm definitely not seeing this. Is this problem a result of non > > upstreamed patches? For sha1, currently the only possible hash > > algorithm, I'm seeing 664.
You won't see it with gcc, only with clang in some randconfig builds, I suppose only when KASAN is enabled.
> Every time a measurement is added to the measurement list, the memory > would be allocated/freed. The frequency of new measurements is policy > dependent. For performance reasons, I'd prefer if the allocation > remains on the stack.
Is there a way to preallocate the shash_desc instead? That would avoid the overhead.
Arnd
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