On Tue, 28 Feb 2012, Ware, Ryan R wrote:

On Tue, Feb 28, 2012 at 7:46 AM, Andrew Morton [off-list ref]wrote:

quoted

On Fri, 24 Feb 2012 19:19:22 -0800 (PST)
Hugh Dickins [off-list ref] wrote:
...

quoted

+             if (!new_xattr->name) {
+                     kfree(new_xattr);
+                     return -ENOMEM;
+             }
+
+             memcpy(new_xattr->name, XATTR_SECURITY_PREFIX,
+                    XATTR_SECURITY_PREFIX_LEN);
+             memcpy(new_xattr->name + XATTR_SECURITY_PREFIX_LEN,
+                    xattr->name, len);
+
+             spin_lock(&info->lock);
+             list_add(&new_xattr->list, &info->xattr_list);
+             spin_unlock(&info->lock);
+     }
+
+     return 0;
+}

So if there's a kmalloc failure partway through the array, we leave a
partially xattrified inode in place.

Are we sure this is OK?

I'm guessing Jarkko can clean that up a bit.  It wouldn't be a good idea to
leave inaccurate data structures laying around during failure cases.

Andrew raises a good concern, but Jarkko got it just right and no
change is needed: any xattrs already allocated are properly linked
on info->xattr_list, then when security_inode_init_security() fails
(with an error other than EOPNOTSUPP) the failing inode is iput(),
which ends up in shmem_evict_inode(), which kfree()s those xattrs
(and their names) on info->xattr_list.

Hugh

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