[PATCH] crypto: crypto_user: Replace GFP_ATOMIC with GFP_KERNEL in crypto_report

[PATCH] crypto: crypto_user: Replace GFP_ATOMIC with GFP_KERNEL in crypto_report

[Jia-Ju Bai]

After checking all possible call chains to crypto_report here,
my tool finds that crypto_report is never called in atomic context.
And crypto_report calls crypto_alg_match which calls down_read, 
thus it proves again that crypto_report can call functions which may sleep.
Thus GFP_ATOMIC is not necessary, and it can be replaced with GFP_KERNEL.

This is found by a static analysis tool named DCNS written by myself.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
---
 crypto/crypto_user.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crypto/crypto_user.c b/crypto/crypto_user.c
index 0dbe2be7..23baef1 100644
--- a/crypto/crypto_user.c
+++ b/crypto/crypto_user.c
@@ -271,7 +271,7 @@ static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
 		return -ENOENT;
 
 	err = -ENOMEM;
-	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
+	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 	if (!skb)
 		goto drop_alg;
 
-- 
1.7.9.5

Re: [PATCH] crypto: crypto_user: Replace GFP_ATOMIC with GFP_KERNEL in crypto_report

[Herbert Xu]

On Thu, Jan 25, 2018 at 06:06:02PM +0800, Jia-Ju Bai wrote:
> After checking all possible call chains to crypto_report here,
> my tool finds that crypto_report is never called in atomic context.
> And crypto_report calls crypto_alg_match which calls down_read, 
> thus it proves again that crypto_report can call functions which may sleep.
> Thus GFP_ATOMIC is not necessary, and it can be replaced with GFP_KERNEL.
> 
> This is found by a static analysis tool named DCNS written by myself.
> 
> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>

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