From: Arnd Bergmann <arnd@arndb.de>

The memory sanitizer causes excessive register spills in this function:

crypto/wp512.c:782:13: error: stack frame size (2104) exceeds limit (2048) in 'wp512_process_buffer' [-Werror,-Wframe-larger-than]

Assume that this one is safe, and mark it as needing no checks to
get the stack usage back down to the normal level.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 crypto/wp512.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crypto/wp512.c b/crypto/wp512.c
index 5e820afa3c78..07994e5ebf4e 100644
--- a/crypto/wp512.c
+++ b/crypto/wp512.c
@@ -779,7 +779,7 @@ static const u64 rc[WHIRLPOOL_ROUNDS] = {
  * The core Whirlpool transform.
  */
 
-static void wp512_process_buffer(struct wp512_ctx *wctx) {
+static __no_kmsan_checks void wp512_process_buffer(struct wp512_ctx *wctx) {
 	int i, r;
 	u64 K[8];        /* the round key */
 	u64 block[8];    /* mu(buffer) */
-- 
2.35.1

On Thu, Dec 15, 2022 at 05:29:38PM +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> The memory sanitizer causes excessive register spills in this function:
> 
> crypto/wp512.c:782:13: error: stack frame size (2104) exceeds limit (2048) in 'wp512_process_buffer' [-Werror,-Wframe-larger-than]
> 
> Assume that this one is safe, and mark it as needing no checks to
> get the stack usage back down to the normal level.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  crypto/wp512.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

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

> The memory sanitizer causes excessive register spills in this function:

> crypto/wp512.c:782:13: error: stack frame size (2104) exceeds limit (2048) in 'wp512_process_buffer' [-Werror,-Wframe-larger-than]

> Assume that this one is safe, and mark it as needing no checks to
> get the stack usage back down to the normal level.

KMSAN indeed bloats the stack frames heavily.
Wouldn't it be more preferable to further increase KMSAN's -Wframe-larger-than limit instead?
It is not intended for production anyway, and detecting a runtime stack overflow in the debug mode should not be a problem.

On Fri, Dec 16, 2022, at 17:08, Alexander Potapenko wrote:
>> The memory sanitizer causes excessive register spills in this function:
>
>> crypto/wp512.c:782:13: error: stack frame size (2104) exceeds limit (2048) in 'wp512_process_buffer' [-Werror,-Wframe-larger-than]
>
>> Assume that this one is safe, and mark it as needing no checks to
>> get the stack usage back down to the normal level.
>
> KMSAN indeed bloats the stack frames heavily.
> Wouldn't it be more preferable to further increase KMSAN's 
> -Wframe-larger-than limit instead?
> It is not intended for production anyway, and detecting a runtime stack 
> overflow in the debug mode should not be a problem.

I don't actually see a lot of compiler warnings with KMSAN
hitting the limit, I think we can deal with them individually.

I'd rather not raise the limit more, as that makes it harder
to identify functions that use more stack than they should.

    Arnd