From: Joe Perches <joe@perches.com>
To: David Hildenbrand <david@redhat.com>,
Bartosz Golaszewski <brgl@bgdev.pl>,
Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Bartosz Golaszewski <bgolaszewski@baylibre.com>
Subject: Re: [PATCH] mm: util: update the kerneldoc for kstrdup_const()
Date: Mon, 29 Jun 2020 12:21:34 -0700 [thread overview]
Message-ID: <644c67ae316bde28669f660aa5aade274d19a2d0.camel@perches.com> (raw)
In-Reply-To: <7f1439be-75c4-3a07-ab7b-f4505bf30c48@redhat.com>
On Mon, 2020-06-29 at 12:54 +0200, David Hildenbrand wrote:
> On 28.06.20 19:37, Joe Perches wrote:
> > On Sun, 2020-06-28 at 17:25 +0200, Bartosz Golaszewski wrote:
> > > From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> > >
> > > Memory allocated with kstrdup_const() must not be passed to regular
> > > krealloc() as it is not aware of the possibility of the chunk residing
> > > in .rodata. Since there are no potential users of krealloc_const()
> > > at the moment, let's just update the doc to make it explicit.
> >
> > Another option would be to return NULL if it's
> > used from krealloc with a pointer into rodata
[]
> > diff --git a/mm/slab_common.c b/mm/slab_common.c
[]
> > @@ -1683,6 +1683,9 @@ static __always_inline void *__do_krealloc(const void *p, size_t new_size,
> > * @new_size: how many bytes of memory are required.
> > * @flags: the type of memory to allocate.
> > *
> > + * If the object pointed to is in rodata (likely from kstrdup_const)
> > + * %NULL is returned.
> > + *
[]
> Won't we have similar issues if somebody would do a kfree() instead of a
> kfree_const()? So I think the original patch makes sense.
Which is why I also suggested making kfree work for
more types of memory freeing earlier this month.
https://lore.kernel.org/lkml/573b3fbd5927c643920e1364230c296b23e7584d.camel@perches.com/
next prev parent reply other threads:[~2020-06-29 19:22 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-28 15:25 [PATCH] mm: util: update the kerneldoc for kstrdup_const() Bartosz Golaszewski
2020-06-28 17:37 ` Joe Perches
2020-06-28 18:06 ` Bartosz Golaszewski
2020-06-28 18:20 ` Joe Perches
2020-06-29 10:54 ` David Hildenbrand
2020-06-29 19:21 ` Joe Perches [this message]
2020-06-30 8:57 ` David Hildenbrand
2020-06-30 14:14 ` Joe Perches
2020-06-30 14:36 ` David Hildenbrand
2020-06-30 14:51 ` Joe Perches
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