Re: [PATCH] ubifs: replay: Fix high stack usage, again

[Nathan Chancellor]

On Thu, Jan 14, 2021 at 10:30:11PM +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@xxxxxxxx>
> 
> An earlier commit moved out some functions to not be inlined by gcc, but
> after some other rework to remove one of those, clang started inlining
> the other one and ran into the same problem as gcc did before:
> 
> fs/ubifs/replay.c:1174:5: error: stack frame size of 1152 bytes in function 'ubifs_replay_journal' [-Werror,-Wframe-larger-than=]
> 
> Mark the function as noinline_for_stack to ensure it doesn't happen
> again.
> 
> Fixes: f80df3851246 ("ubifs: use crypto_shash_tfm_digest()")
> Fixes: eb66eff6636d ("ubifs: replay: Fix high stack usage")
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>

Reviewed-by: Nathan Chancellor <natechancellor@xxxxxxxxx>

> ---
>  fs/ubifs/replay.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/ubifs/replay.c b/fs/ubifs/replay.c
> index 79801c9a5b87..0f8a6a16421b 100644
> --- a/fs/ubifs/replay.c
> +++ b/fs/ubifs/replay.c
> @@ -559,7 +559,9 @@ static int is_last_bud(struct ubifs_info *c, struct ubifs_bud *bud)
>  }
>  
>  /* authenticate_sleb_hash is split out for stack usage */
> -static int authenticate_sleb_hash(struct ubifs_info *c, struct shash_desc *log_hash, u8 *hash)
> +static int noinline_for_stack
> +authenticate_sleb_hash(struct ubifs_info *c,
> +		       struct shash_desc *log_hash, u8 *hash)
>  {
>  	SHASH_DESC_ON_STACK(hash_desc, c->hash_tfm);
>  
> -- 
> 2.29.2
>