From: Andrew Morton <akpm@linux-foundation.org>
To: Jiri Kosina <jkosina@suse.cz>
Cc: Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Dan Carpenter <dan.carpenter@oracle.com>,
Theodore Ts'o <tytso@mit.edu>
Subject: Re: [PATCH] mm/sl[aou]b: make kfree() aware of error pointers
Date: Tue, 9 Sep 2014 16:21:14 -0700 [thread overview]
Message-ID: <20140909162114.44b3e98cf925f125e84a8a06@linux-foundation.org> (raw)
In-Reply-To: <alpine.LNX.2.00.1409092319370.5523@pobox.suse.cz>
On Tue, 9 Sep 2014 23:25:28 +0200 (CEST) Jiri Kosina <jkosina@suse.cz> wrote:
> kfree() is happy to accept NULL pointer and does nothing in such case.
> It's reasonable to expect it to behave the same if ERR_PTR is passed to
> it.
>
> Inspired by a9cfcd63e8d ("ext4: avoid trying to kfree an ERR_PTR
> pointer").
>
> ...
>
> --- a/mm/slab.c
> +++ b/mm/slab.c
> @@ -3612,7 +3612,7 @@ void kfree(const void *objp)
>
> trace_kfree(_RET_IP_, objp);
>
> - if (unlikely(ZERO_OR_NULL_PTR(objp)))
> + if (unlikely(ZERO_OR_NULL_PTR(objp) || IS_ERR(objp)))
> return;
kfree() is quite a hot path to which this will add overhead. And we
have (as far as we know) no code which will actually use this at
present.
How about a new
kfree_safe(...)
{
if (IS_ERR(...))
return;
if (other-stuff-when-we-think-of-it)
return;
kfree(...);
}
?
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next prev parent reply other threads:[~2014-09-09 23:21 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-09 21:25 [PATCH] mm/sl[aou]b: make kfree() aware of error pointers Jiri Kosina
2014-09-09 23:21 ` Andrew Morton [this message]
2014-09-10 5:05 ` Jiri Kosina
2014-09-10 5:11 ` Andrew Morton
2014-09-10 6:36 ` Dan Carpenter
2014-09-10 13:56 ` Theodore Ts'o
2014-09-10 14:27 ` Dave Jones
2014-09-10 14:07 ` Theodore Ts'o
2014-09-10 14:24 ` Jiri Kosina
2014-09-10 14:33 ` Andrey Ryabinin
2014-09-10 14:42 ` Jiri Kosina
2014-09-10 15:43 ` Christoph Lameter
2014-09-10 14:26 ` Jiri Kosina
2014-09-10 15:21 ` Dan Carpenter
2014-09-10 15:28 ` Jiri Kosina
2014-09-10 15:53 ` Dan Carpenter
2014-09-10 19:40 ` Theodore Ts'o
2014-09-11 14:14 ` Rasmus Villemoes
2014-09-10 14:22 ` Christoph Lameter
2014-09-10 5:15 ` Valdis.Kletnieks
2014-09-10 6:51 ` Dan Carpenter
2014-09-10 13:59 ` Christoph Lameter
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