From: Thorsten Blum <thorsten.blum@linux.dev>
To: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>,
Alexander Gordeev <agordeev@linux.ibm.com>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Sven Schnelle <svens@linux.ibm.com>,
linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] s390/hypfs_sprp: Replace kzalloc() + copy_from_user() with memdup_user()
Date: Fri, 12 Sep 2025 14:50:12 +0200 [thread overview]
Message-ID: <BABCE4F4-7C7A-4D25-AFB6-1CF9476151A9@linux.dev> (raw)
In-Reply-To: <20250912110619.10147C7e-hca@linux.ibm.com>
On 12. Sep 2025, at 13:06, Heiko Carstens wrote:
> On Fri, Sep 12, 2025 at 12:09:43PM +0200, Thorsten Blum wrote:
>> On 12. Sep 2025, at 11:56, Heiko Carstens wrote:
>>> This is not an improvement and also incorrect, since kfree() may now
>>> be called with an error pointer.
>>
>> Unless I'm missing something, kfree() works just fine with error
>> pointers. See linux/slab.h:
>>
>> DEFINE_FREE(kfree, void *, if (!IS_ERR_OR_NULL(_T)) kfree(_T))
>
> This is for automatically freed memory, but not for the generic case.
> See cd7eb8f83fcf ("mm/slab: make __free(kfree) accept error pointers").
Interesting, I didn't know this doesn't work for the generic kfree().
Thanks,
Thorsten
prev parent reply other threads:[~2025-09-12 12:50 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-11 21:45 [PATCH] s390/hypfs_sprp: Replace kzalloc() + copy_from_user() with memdup_user() Thorsten Blum
2025-09-12 9:56 ` Heiko Carstens
2025-09-12 10:09 ` Thorsten Blum
2025-09-12 10:51 ` Thorsten Blum
2025-09-12 11:10 ` Heiko Carstens
2025-09-12 11:06 ` Heiko Carstens
2025-09-12 12:50 ` Thorsten Blum [this message]
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