[PATCH] proc: add error handling for kmem_cache_create

[PATCH] proc: add error handling for kmem_cache_create

[Zhouyang Jia]

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 <jiazhouyang09@gmail.com>
---
 fs/proc/inode.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index 2cf3b74..5d8b2d1 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -104,6 +104,9 @@ void __init proc_init_kmemcache(void)
 	pde_opener_cache =
 		kmem_cache_create("pde_opener", sizeof(struct pde_opener), 0,
 				  SLAB_ACCOUNT|SLAB_PANIC, NULL);
+	if (!proc_inode_cachep || !pde_opener_cache)
+		return -ENOMEM;
+
 	proc_dir_entry_cache = kmem_cache_create_usercopy(
 		"proc_dir_entry", sizeof(struct proc_dir_entry), 0, SLAB_PANIC,
 		offsetof(struct proc_dir_entry, inline_name),
-- 
2.7.4

Re: [PATCH] proc: add error handling for kmem_cache_create

[Alexey Dobriyan]

On Tue, Jun 12, 2018 at 12:23:52PM +0800, Zhouyang Jia 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.

>  	pde_opener_cache =
>  		kmem_cache_create("pde_opener", sizeof(struct pde_opener), 0,
>  				  SLAB_ACCOUNT|SLAB_PANIC, NULL);
> +	if (!proc_inode_cachep || !pde_opener_cache)
> +		return -ENOMEM;

SLAB_PANIC was added to not worry about error handling.

Re: [PATCH] proc: add error handling for kmem_cache_create

[kbuild test robot]

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Hi,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on v4.17 next-20180608]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/linux-kernel-owner-vger-kernel-org/proc-add-error-handling-for-kmem_cache_create/20180612-122737
config: i386-randconfig-x012-201823 (attached as .config)
compiler: gcc-7 (Debian 7.3.0-16) 7.3.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All warnings (new ones prefixed by >>):

   fs/proc/inode.c: In function 'proc_init_kmemcache':
>> fs/proc/inode.c:108:10: warning: 'return' with a value, in function returning void
      return -ENOMEM;
             ^
   fs/proc/inode.c:96:13: note: declared here
    void __init proc_init_kmemcache(void)
                ^~~~~~~~~~~~~~~~~~~

vim +/return +108 fs/proc/inode.c

    95	
    96	void __init proc_init_kmemcache(void)
    97	{
    98		proc_inode_cachep = kmem_cache_create("proc_inode_cache",
    99						     sizeof(struct proc_inode),
   100						     0, (SLAB_RECLAIM_ACCOUNT|
   101							SLAB_MEM_SPREAD|SLAB_ACCOUNT|
   102							SLAB_PANIC),
   103						     init_once);
   104		pde_opener_cache =
   105			kmem_cache_create("pde_opener", sizeof(struct pde_opener), 0,
   106					  SLAB_ACCOUNT|SLAB_PANIC, NULL);
   107		if (!proc_inode_cachep || !pde_opener_cache)
 > 108			return -ENOMEM;
   109	
   110		proc_dir_entry_cache = kmem_cache_create_usercopy(
   111			"proc_dir_entry", sizeof(struct proc_dir_entry), 0, SLAB_PANIC,
   112			offsetof(struct proc_dir_entry, inline_name),
   113			sizeof_field(struct proc_dir_entry, inline_name), NULL);
   114	}
   115	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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