Re: [PATCH] scripts/kernel-doc: match -Werror flag strictly

[Jonathan Corbet <corbet@lwn.net>]

Yujie Liu <yujie.liu@intel.com> writes:

> In our CI testing, we use some commands as below to only turn a specific
> type of warnings into errors, but we notice that kernel-doc warnings
> are also turned into errors unexpectedly.
>
> $ make KCFLAGS="-Werror=return-type" W=1 kernel/fork.o
>
> kernel/fork.c:1406: warning: Function parameter or member 'mm' not described in 'set_mm_exe_file'
> kernel/fork.c:1406: warning: Function parameter or member 'new_exe_file' not described in 'set_mm_exe_file'
> kernel/fork.c:1441: warning: Function parameter or member 'mm' not described in 'replace_mm_exe_file'
> kernel/fork.c:1441: warning: Function parameter or member 'new_exe_file' not described in 'replace_mm_exe_file'
> kernel/fork.c:1491: warning: Function parameter or member 'mm' not described in 'get_mm_exe_file'
> kernel/fork.c:1510: warning: Function parameter or member 'task' not described in 'get_task_exe_file'
> kernel/fork.c:1534: warning: Function parameter or member 'task' not described in 'get_task_mm'
> kernel/fork.c:2109: warning: bad line:
> kernel/fork.c:2130: warning: Function parameter or member 'ret' not described in '__pidfd_prepare'
> kernel/fork.c:2130: warning: Excess function parameter 'pidfd' description in '__pidfd_prepare'
> kernel/fork.c:2179: warning: Function parameter or member 'ret' not described in 'pidfd_prepare'
> kernel/fork.c:2179: warning: Excess function parameter 'pidfd' description in 'pidfd_prepare'
> kernel/fork.c:3195: warning: expecting prototype for clone3(). Prototype was for sys_clone3() instead
> 13 warnings as Errors
> make[3]: *** [scripts/Makefile.build:243: kernel/fork.o] Error 13
> make[3]: *** Deleting file 'kernel/fork.o'
> make[2]: *** [scripts/Makefile.build:480: kernel] Error 2
> make[1]: *** [/root/linux/Makefile:1913: .] Error 2
> make: *** [Makefile:234: __sub-make] Error 2
>
> From the git history, commit 2c12c8103d8f ("scripts/kernel-doc:
> optionally treat warnings as errors") introduces a new command-line
> option to make kernel-doc warnings into errors. It can also read the
> KCFLAGS environment variable to decide whether to turn this option on,
> but the regex used for matching may not be accurate enough. It can match
> both "-Werror" and "-Werror=<diagnostic-type>", so the option is turned
> on by mistake in the latter case.
>
> Fix this by strictly matching the flag "-Werror": there must be a space
> or start of string in the front, and a space or end of string at the
> end. This can handle all the following cases correctly:
>
> KCFLAGS="-Werror" make W=1 [MATCH]
> KCFLAGS="-Werror=return-type" make W=1 [NO MATCH]
> KCFLAGS="-Wcomment -Werror -Wundef" make W=1 [MATCH]
> KCFLAGS="-Wcomment -Werror=return-type -Wundef" make W=1 [NO MATCH]
>
> Fixes: 2c12c8103d8f ("scripts/kernel-doc: optionally treat warnings as errors")
> Signed-off-by: Yujie Liu <yujie.liu@intel.com>
> ---
>  scripts/kernel-doc | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Applied, thanks,

jon