[Linux-kernel-mentees] [PATCH] checkpatch: fix false positive for REPEATED_WORD warning
Aditya
yashsri421 at gmail.com
Wed Oct 21 05:15:51 UTC 2020
On 21/10/20 10:30 am, Aditya Srivastava wrote:
> Presence of hexadecimal address or symbol results in false warning
> message by checkpatch.pl.
>
> For example, running checkpatch on commit b8ad540dd4e4 ("mptcp: fix
> memory leak in mptcp_subflow_create_socket()") results in warning:
>
> WARNING:REPEATED_WORD: Possible repeated word: 'ff'
> 00 00 00 00 00 00 00 00 00 2f 30 0a 81 88 ff ff ........./0.....
>
> Here, it reports 'ff' to be repeated, but it is infact part of some
> address or code, where it has to be repeated. Thus the warning seems
> unnecessary in this case.
>
> To avoid all such reports, add an additional regex check for a repeating
> pattern of 4 or more 2-lettered words separated by space in a line.
>
> Signed-off-by: Aditya Srivastava <yashsri421 at gmail.com>
> ---
> scripts/checkpatch.pl | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 9b9ffd876e8a..181c95691715 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -3052,7 +3052,9 @@ sub process {
>
> # check for repeated words separated by a single space
> if ($rawline =~ /^\+/ || $in_commit_log) {
> - while ($rawline =~ /\b($word_pattern) (?=($word_pattern))/g) {
> + # avoid repeating hex occurrences like 'ff ff fe 09 ...'
> + while ($rawline !~ /((\s)*[0-9a-z]{2}( )+){4,}/ &&
> + $rawline =~ /\b($word_pattern) (?=($word_pattern))/g) {
>
> my $first = $1;
> my $second = $2;
>
Report of the impact of patch/changes(taken over v5.6..v5.8):
List of errors and warnings after applying the patch:
https://github.com/AdityaSrivast/kernel-tasks/blob/master/Task3/summary.txt
Change in errors and warnings compared to previous patch:
https://github.com/AdityaSrivast/kernel-tasks/blob/master/Task3/relative_summary/summary_relative.txt
Impact/Conclusion:
It can be seen that a large amount of warning messages under
REPEATED_WORD were because of such hex occurrences.
The changes made reduces the warning count of REPEATED_WORD by more
than 60%, ie. from 2797 to 1015 (over v5.6..v5.8)
Aditya
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