From f4844b35d68ab49c41d542c501fffb46ad81009a Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Sun, 24 Mar 2019 20:44:51 +0100 Subject: [PATCH] ubifs: work around high stack usage with clang Building this file with clang can result in large stack usage as seen from this warning: fs/ubifs/auth.c:78:5: error: stack frame size of 1152 bytes in function 'ubifs_prepare_auth_node' The problem is that inlining ubifs_hash_calc_hmac() leads to two SHASH_DESC_ON_STACK() blocks in the same function, and clang for some reason does not reuse the stack space as it should. Putting the first declaration into a separate basic block avoids this problem and reduces the stack allocation to 640 bytes. Signed-off-by: Arnd Bergmann Reviewed-by: Nick Desaulniers Signed-off-by: Richard Weinberger --- fs/ubifs/auth.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/fs/ubifs/auth.c b/fs/ubifs/auth.c index 2a40ccce..3d04919 100644 --- a/fs/ubifs/auth.c +++ b/fs/ubifs/auth.c @@ -78,7 +78,6 @@ static int ubifs_hash_calc_hmac(const struct ubifs_info *c, const u8 *hash, int ubifs_prepare_auth_node(struct ubifs_info *c, void *node, struct shash_desc *inhash) { - SHASH_DESC_ON_STACK(hash_desc, c->hash_tfm); struct ubifs_auth_node *auth = node; u8 *hash; int err; @@ -87,13 +86,17 @@ int ubifs_prepare_auth_node(struct ubifs_info *c, void *node, if (!hash) return -ENOMEM; - hash_desc->tfm = c->hash_tfm; - hash_desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; - ubifs_shash_copy_state(c, inhash, hash_desc); + { + SHASH_DESC_ON_STACK(hash_desc, c->hash_tfm); - err = crypto_shash_final(hash_desc, hash); - if (err) - goto out; + hash_desc->tfm = c->hash_tfm; + hash_desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; + ubifs_shash_copy_state(c, inhash, hash_desc); + + err = crypto_shash_final(hash_desc, hash); + if (err) + goto out; + } err = ubifs_hash_calc_hmac(c, hash, auth->hmac); if (err) -- 2.7.4