[PATCH] nfs: Ignore kmemleak false positive in nfs_readdir_make_qstr

[PATCH] nfs: Ignore kmemleak false positive in nfs_readdir_make_qstr

[Catalin Marinas]

Strings allocated via kmemdup() in nfs_readdir_make_qstr() are
referenced from the nfs_cache_array which is stored in a page cache
page. Kmemleak does not scan such pages and it reports several false
positives. This patch annotates the string->name pointer so that
kmemleak does not consider it a real leak.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Bryan Schumaker <bjschuma@netapp.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
---
 fs/nfs/dir.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 07ac384..a9f9e14 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -34,6 +34,7 @@
 #include <linux/mount.h>
 #include <linux/sched.h>
 #include <linux/vmalloc.h>
+#include <linux/kmemleak.h>
 
 #include "delegation.h"
 #include "iostat.h"
@@ -231,6 +232,11 @@ int nfs_readdir_make_qstr(struct qstr *string, const char *name, unsigned int le
 	string->name = kmemdup(name, len, GFP_KERNEL);
 	if (string->name == NULL)
 		return -ENOMEM;
+	/*
+	 * Avoid a kmemleak false positive. The pointer to the name is stored
+	 * in a page cache page which kmemleak does not scan.
+	 */
+	kmemleak_not_leak(string->name);
 	string->hash = full_name_hash(name, len);
 	return 0;
 }
-- 
1.7.3.GIT

Re: [PATCH] nfs: Ignore kmemleak false positive in nfs_readdir_make_qstr

[Bryan Schumaker]

Thanks!  The patch works for me.

Bryan

On 11/11/2010 07:53 AM, Catalin Marinas wrote:
> Strings allocated via kmemdup() in nfs_readdir_make_qstr() are
> referenced from the nfs_cache_array which is stored in a page cache
> page. Kmemleak does not scan such pages and it reports several false
> positives. This patch annotates the string->name pointer so that
> kmemleak does not consider it a real leak.
> 
> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Bryan Schumaker <bjschuma@netapp.com>
> Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
> ---
>  fs/nfs/dir.c |    6 ++++++
>  1 files changed, 6 insertions(+), 0 deletions(-)
> 
> diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
> index 07ac384..a9f9e14 100644
> --- a/fs/nfs/dir.c
> +++ b/fs/nfs/dir.c
> @@ -34,6 +34,7 @@
>  #include <linux/mount.h>
>  #include <linux/sched.h>
>  #include <linux/vmalloc.h>
> +#include <linux/kmemleak.h>
>  
>  #include "delegation.h"
>  #include "iostat.h"
> @@ -231,6 +232,11 @@ int nfs_readdir_make_qstr(struct qstr *string, const char *name, unsigned int le
>  	string->name = kmemdup(name, len, GFP_KERNEL);
>  	if (string->name == NULL)
>  		return -ENOMEM;
> +	/*
> +	 * Avoid a kmemleak false positive. The pointer to the name is stored
> +	 * in a page cache page which kmemleak does not scan.
> +	 */
> +	kmemleak_not_leak(string->name);
>  	string->hash = full_name_hash(name, len);
>  	return 0;
>  }