From: Joe Perches <joe@perches.com>
To: Andrew Morton <akpm@linux-foundation.org>,
Julia Lawall <julia.lawall@lip6.fr>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Minchan Kim <minchan@kernel.org>,
Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Michal Hocko <mhocko@suse.cz>,
David Rientjes <rientjes@google.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
sergey.senozhatsky.work@gmail.com
Subject: Re: [RFC][PATCH 0/5] do not dereference NULL pools in pools' destroy() functions
Date: Tue, 09 Jun 2015 17:06:09 -0700 [thread overview]
Message-ID: <1433894769.2730.87.camel@perches.com> (raw)
In-Reply-To: <20150609142523.b717dba6033ee08de997c8be@linux-foundation.org>
On Tue, 2015-06-09 at 14:25 -0700, Andrew Morton wrote:
> On Tue, 9 Jun 2015 21:04:48 +0900 Sergey Senozhatsky <sergey.senozhatsky@gmail.com> wrote:
>
> > The existing pools' destroy() functions do not allow NULL pool pointers;
> > instead, every destructor() caller forced to check if pool is not NULL,
> > which:
> > a) requires additional attention from developers/reviewers
> > b) may lead to a NULL pointer dereferences if (a) didn't work
> >
> >
> > First 3 patches tweak
> > - kmem_cache_destroy()
> > - mempool_destroy()
> > - dma_pool_destroy()
> >
> > to handle NULL pointers.
>
> Well I like it, even though it's going to cause a zillion little cleanup
> patches.
>
> checkpatch already has a "kfree(NULL) is safe and this check is
> probably not required" test so I guess Joe will need to get busy ;)
Maybe it'll be Julia's crew.
The checkpatch change is pretty trivial
---
scripts/checkpatch.pl | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 69c4716..3d6e34d 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -4801,7 +4801,7 @@ sub process {
# check for needless "if (<foo>) fn(<foo>)" uses
if ($prevline =~ /\bif\s*\(\s*($Lval)\s*\)/) {
my $expr = '\s*\(\s*' . quotemeta($1) . '\s*\)\s*;';
- if ($line =~ /\b(kfree|usb_free_urb|debugfs_remove(?:_recursive)?)$expr/) {
+ if ($line =~ /\b(kfree|usb_free_urb|debugfs_remove(?:_recursive)?|(?:kmem_cache|mempool|dma_pool)_destroy)$expr/) {
WARN('NEEDLESS_IF',
"$1(NULL) is safe and this check is probably not required\n" . $hereprev);
}
next prev parent reply other threads:[~2015-06-10 0:06 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-09 12:04 [RFC][PATCH 0/5] do not dereference NULL pools in pools' destroy() functions Sergey Senozhatsky
2015-06-09 12:04 ` [RFC][PATCH 1/5] mm/slab_common: allow NULL cache pointer in kmem_cache_destroy() Sergey Senozhatsky
2015-06-17 23:14 ` David Rientjes
2015-06-17 23:52 ` Sergey Senozhatsky
2015-06-19 15:50 ` Julia Lawall
2015-08-06 14:21 ` Sergey Senozhatsky
2015-08-06 14:27 ` Julia Lawall
2015-08-06 14:29 ` Sergey Senozhatsky
2015-06-20 16:25 ` Julia Lawall
2015-07-16 8:26 ` Sergey Senozhatsky
2015-06-09 12:04 ` [RFC][PATCH 2/5] mm/mempool: allow NULL `pool' pointer in mempool_destroy() Sergey Senozhatsky
2015-06-17 23:21 ` David Rientjes
2015-06-17 23:54 ` Sergey Senozhatsky
2015-06-09 12:04 ` [RFC][PATCH 3/5] mm/dmapool: allow NULL `pool' pointer in dma_pool_destroy() Sergey Senozhatsky
2015-06-17 23:22 ` David Rientjes
2015-06-09 12:04 ` [RFC][PATCH 4/5] mm/zpool: allow NULL `zpool' pointer in zpool_destroy_pool() Sergey Senozhatsky
2015-06-10 20:59 ` Dan Streetman
2015-06-10 23:58 ` Sergey Senozhatsky
2015-06-11 0:48 ` Joe Perches
2015-06-11 0:59 ` Sergey Senozhatsky
2015-06-11 1:01 ` Dan Streetman
2015-06-09 12:04 ` [RFC][PATCH 5/5] mm/zsmalloc: allow NULL `pool' pointer in zs_destroy_pool() Sergey Senozhatsky
2015-06-09 21:25 ` [RFC][PATCH 0/5] do not dereference NULL pools in pools' destroy() functions Andrew Morton
2015-06-10 0:06 ` Joe Perches [this message]
2015-06-10 4:39 ` [PATCH] checkpatch: Add some <foo>_destroy functions to NEEDLESS_IF tests Joe Perches
2015-06-10 5:52 ` [PATCH V2] " Joe Perches
2015-06-10 10:18 ` Sergey Senozhatsky
2015-06-11 9:41 ` Julia Lawall
2015-06-11 9:51 ` Sergey Senozhatsky
2015-06-11 9:55 ` Julia Lawall
2015-07-14 23:03 ` Andrew Morton
2015-07-15 0:27 ` Sergey Senozhatsky
2015-06-10 5:46 ` [RFC][PATCH 0/5] do not dereference NULL pools in pools' destroy() functions Julia Lawall
2015-06-10 6:41 ` Sergey Senozhatsky
2015-06-10 6:44 ` Julia Lawall
2015-06-10 6:52 ` Sergey Senozhatsky
2015-06-10 1:11 ` Christoph Lameter
2015-06-10 1:51 ` Andrew Morton
2015-06-10 2:00 ` Christoph Lameter
2015-06-10 2:17 ` Andrew Morton
2015-06-10 4:47 ` Joe Perches
2015-06-11 17:26 ` Christoph Lameter
2015-06-11 17:40 ` Andrew Morton
2015-06-10 2:04 ` Sergey Senozhatsky
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