linux-kernel - Re: [PATCH] ext4: hash: change kzalloc(n * sizeof, ...) to kcalloc(n, sizeof, ...)

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-Id: <55E18A5B-49D0-4E8D-A252-DC7EF0BA691D@dilger.ca>
Date: Sat, 15 Mar 2025 23:27:02 -0600
From: Andreas Dilger <adilger@...ger.ca>
To: Matthew Wilcox <willy@...radead.org>
Cc: Ethan Carter Edwards <ethan@...ancedwards.com>,
 Theodore Ts'o <tytso@....edu>,
 Ext4 Developers List <linux-ext4@...r.kernel.org>,
 LKML <linux-kernel@...r.kernel.org>,
 linux-fsdevel <linux-fsdevel@...r.kernel.org>,
 linux-hardening@...r.kernel.org
Subject: Re: [PATCH] ext4: hash: change kzalloc(n * sizeof, ...) to kcalloc(n,
 sizeof, ...)

On Mar 15, 2025, at 9:28 PM, Matthew Wilcox <willy@...radead.org> wrote:
> 
> On Sat, Mar 15, 2025 at 12:29:34PM -0400, Ethan Carter Edwards wrote:
>> Open coded arithmetic in allocator arguments is discouraged. Helper
>> functions like kcalloc are preferred.
> 
> Well, yes, but ...
> 
>> +++ b/fs/ext4/hash.c
>> @@ -302,7 +302,7 @@ int ext4fs_dirhash(const struct inode *dir, const char *name, int len,
>> 
>> 	if (len && IS_CASEFOLDED(dir) &&
>> 	   (!IS_ENCRYPTED(dir) || fscrypt_has_encryption_key(dir))) {
>> -		buff = kzalloc(sizeof(char) * PATH_MAX, GFP_KERNEL);
>> +		buff = kcalloc(PATH_MAX, sizeof(char), GFP_KERNEL);
> 
> sizeof(char) is defined to be 1.  So this should just be
> kzalloc(PATH_MAX, GFP_KERNEL).

I was going to say exactly the same thing.
Passing "1" to kcalloc() is just pure overhead.

Cheers, Andreas






Download attachment "signature.asc" of type "application/pgp-signature" (874 bytes)