2018-06-12 04:20:19

by Zhouyang Jia

Subject: [PATCH] fanotify: add error handling for kmem_cache_create

When kmem_cache_create fails, the lack of error-handling code may
cause unexpected results.

This patch adds error-handling code after calling kmem_cache_create.

Signed-off-by: Zhouyang Jia <[email protected]>
---
fs/notify/fanotify/fanotify_user.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index ec4d8c5..e3fa861 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -959,9 +959,14 @@ static int __init fanotify_user_setup(void)
{
fanotify_mark_cache = KMEM_CACHE(fsnotify_mark, SLAB_PANIC);
fanotify_event_cachep = KMEM_CACHE(fanotify_event_info, SLAB_PANIC);
+ if (!fanotify_mark_cache || !fanotify_event_cachep)
+ return -ENOMEM;
+
if (IS_ENABLED(CONFIG_FANOTIFY_ACCESS_PERMISSIONS)) {
fanotify_perm_event_cachep =
KMEM_CACHE(fanotify_perm_event_info, SLAB_PANIC);
+ if (!fanotify_perm_event_cachep)
+ return -ENOMEM;
}

return 0;
--
2.7.4

2018-06-12 05:38:32

by Amir Goldstein

Subject: Re: [PATCH] fanotify: add error handling for kmem_cache_create

On Tue, Jun 12, 2018 at 7:19 AM, Zhouyang Jia <[email protected]> wrote:
> When kmem_cache_create fails, the lack of error-handling code may
> cause unexpected results.
>
> This patch adds error-handling code after calling kmem_cache_create.
>
> Signed-off-by: Zhouyang Jia <[email protected]>
> ---
> fs/notify/fanotify/fanotify_user.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
> index ec4d8c5..e3fa861 100644
> --- a/fs/notify/fanotify/fanotify_user.c
> +++ b/fs/notify/fanotify/fanotify_user.c
> @@ -959,9 +959,14 @@ static int __init fanotify_user_setup(void)
> {
> fanotify_mark_cache = KMEM_CACHE(fsnotify_mark, SLAB_PANIC);
> fanotify_event_cachep = KMEM_CACHE(fanotify_event_info, SLAB_PANIC);
> + if (!fanotify_mark_cache || !fanotify_event_cachep)
> + return -ENOMEM;

If only one failed need to free the other.

> +
> if (IS_ENABLED(CONFIG_FANOTIFY_ACCESS_PERMISSIONS)) {
> fanotify_perm_event_cachep =
> KMEM_CACHE(fanotify_perm_event_info, SLAB_PANIC);
> + if (!fanotify_perm_event_cachep)
> + return -ENOMEM;

here as well.
best implement as goto fail

> }
>
> return 0;

fail:
if (fanotify_mark_cache)
kmem_cache_destroy(fanotify_mark_cache);
...
return -ENOMEM;

Thanks,
Amir.