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  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Date:   Tue,  5 Oct 2021 08:26:11 -0700
From:   Kees Cook <>
To:     Jonathan Corbet <>
Cc:     Kees Cook <>,
        Randy Dunlap <>,
        Joe Perches <>,
        Alexey Dobriyan <>,
        Nick Desaulniers <>,
        Linus Torvalds <>,
        Rasmus Villemoes <>,
        Andrew Morton <>,,,,
        Miguel Ojeda <>
Subject: [PATCH v5] docs: Explain the desired position of function attributes

While discussing how to format the addition of various function
attributes, some "unwritten rules" of ordering surfaced[1]. Capture as
close as possible to Linus's preferences for future reference.

(Though I note the dissent voiced by Joe Perches, Alexey Dobriyan, and
others that would prefer all attributes live on a separate leading line.)


Signed-off-by: Kees Cook <>
- drop extern (joe)
- fix __malloc position (miguel)
 Documentation/process/coding-style.rst | 37 +++++++++++++++++++++++++-
 1 file changed, 36 insertions(+), 1 deletion(-)

diff --git a/Documentation/process/coding-style.rst b/Documentation/process/coding-style.rst
index 42969ab37b34..5756ff775233 100644
--- a/Documentation/process/coding-style.rst
+++ b/Documentation/process/coding-style.rst
@@ -480,13 +480,48 @@ closing function brace line.  E.g.:
+6.1) Function prototypes
 In function prototypes, include parameter names with their data types.
 Although this is not required by the C language, it is preferred in Linux
 because it is a simple way to add valuable information for the reader.
-Do not use the ``extern`` keyword with function prototypes as this makes
+Do not use the ``extern`` keyword with function declarations as this makes
 lines longer and isn't strictly necessary.
+When writing function prototypes, please keep the `order of elements regular
+For example, using this function declaration example::
+ __init void * __must_check action(enum magic value, size_t size, u8 count,
+				   char *fmt, ...) __printf(4, 5) __malloc;
+The preferred order of elements for a function prototype is:
+- storage class (below, ``static __always_inline``, noting that ``__always_inline``
+  is technically an attribute but is treated like ``inline``)
+- storage class attributes (here, ``__init`` -- i.e. section declarations, but also
+  things like ``__cold``)
+- return type (here, ``void *``)
+- return type attributes (here, ``__must_check``)
+- function name (here, ``action``)
+- function parameters (here, ``(enum magic value, size_t size, u8 count, char *fmt, ...)``,
+  noting that parameter names should always be included)
+- function parameter attributes (here, ``__printf(4, 5)``)
+- function behavior attributes (here, ``__malloc``)
+Note that for a function **definition** (i.e. the actual function body),
+the compiler does not allow function parameter attributes after the
+function parameters. In these cases, they should go after the storage
+class attributes (e.g. note the changed position of ``__printf(4, 5)``
+below, compared to the **declaration** example above)::
+ static __always_inline __init __printf(4, 5) void * __must_check action(enum magic value,
+		size_t size, u8 count, char *fmt, ...) __malloc
+ {
+	...
+ }
 7) Centralized exiting of functions

Powered by blists - more mailing lists