2021-01-14 21:34:17

by Arnd Bergmann

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

From: Arnd Bergmann <[email protected]>

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 <[email protected]>
---
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

2021-01-15 18:40:56

by Nathan Chancellor

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

On Thu, Jan 14, 2021 at 10:30:11PM +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <[email protected]>
>
> 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 <[email protected]>

Reviewed-by: Nathan Chancellor <[email protected]>

> ---
> 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
>