linux-kernel - Re: [PATCH] net: bcmgenet: Fix NULL vs IS

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Sat, 11 Dec 2021 18:42:19 -0800
From:   Joe Perches <joe@...ches.com>
To:     Miaoqian Lin <linmq006@...il.com>,
        Dan Carpenter <error27@...il.com>
Cc:     Doug Berger <opendmb@...il.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        bcm-kernel-feedback-list@...adcom.com, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] net: bcmgenet: Fix NULL vs IS_ERR() checking

On Sat, 2021-12-11 at 14:01 +0000, Miaoqian Lin wrote:
> The phy_attach() function does not return NULL. It returns error pointers.

Perhaps all the functions that return error pointers rather than
NULL on error should be marked with a special attribute:

Something like:

#define __returns_nonnull	__attribute__((__returns_nonnull__))

---

 include/linux/compiler_attributes.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/include/linux/compiler_attributes.h b/include/linux/compiler_attributes.h
index 37e2600202216..e2351a36dda97 100644
--- a/include/linux/compiler_attributes.h
+++ b/include/linux/compiler_attributes.h
@@ -250,6 +250,18 @@
 # define __no_profile
 #endif
 
+/*
+ * Optional: only supported since GCC >= 5.x
+ *
+ *      gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-returns_005fnonnull-function-attribute
+ *    clang: https://clang.llvm.org/docs/AttributeReference.html#returns-nonnull
+ */
+#if __has_attribute(__returns_nonnull__)
+# define __returns_nonnull		__attribute__((__returns_nonnull__))
+#else
+# define __returns_nonnull
+#endif
+
 /*
  *   gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-noreturn-function-attribute
  * clang: https://clang.llvm.org/docs/AttributeReference.html#noreturn