diff options
authorMrinal Pandey <>2020-09-04 16:35:52 -0700
committerLinus Torvalds <>2020-09-05 12:14:29 -0700
commit13e45417cedbfc44b1926124b1846f5ee8c6ba4a (patch)
parentb0daa2c73f3a8ab9183a9d298495b583b6c1bd19 (diff)
checkpatch: fix the usage of capture group ( ... )
The usage of "capture group (...)" in the immediate condition after `&&` results in `$1` being uninitialized. This issues a warning "Use of uninitialized value $1 in regexp compilation at ./scripts/ line 2638". I noticed this bug while running checkpatch on the set of commits from v5.7 to v5.8-rc1 of the kernel on the commits with a diff content in their commit message. This bug was introduced in the script by commit e518e9a59ec3 ("checkpatch: emit an error when there's a diff in a changelog"). It has been in the script since then. The author intended to store the match made by capture group in variable `$1`. This should have contained the name of the file as `[\w/]+` matched. However, this couldn't be accomplished due to usage of capture group and `$1` in the same regular expression. Fix this by placing the capture group in the condition before `&&`. Thus, `$1` can be initialized to the text that capture group matches thereby setting it to the desired and required value. Fixes: e518e9a59ec3 ("checkpatch: emit an error when there's a diff in a changelog") Signed-off-by: Mrinal Pandey <> Signed-off-by: Andrew Morton <> Tested-by: Lukas Bulwahn <> Reviewed-by: Lukas Bulwahn <> Cc: Joe Perches <> Link: Signed-off-by: Linus Torvalds <>
1 files changed, 2 insertions, 2 deletions
diff --git a/scripts/ b/scripts/
index 60d4a79674b6..504d2e431c60 100755
--- a/scripts/
+++ b/scripts/
@@ -2639,8 +2639,8 @@ sub process {
# Check if the commit log has what seems like a diff which can confuse patch
if ($in_commit_log && !$commit_log_has_diff &&
- (($line =~ m@^\s+diff\b.*a/[\w/]+@ &&
- $line =~ m@^\s+diff\b.*a/([\w/]+)\s+b/$1\b@) ||
+ (($line =~ m@^\s+diff\b.*a/([\w/]+)@ &&
+ $line =~ m@^\s+diff\b.*a/[\w/]+\s+b/$1\b@) ||
$line =~ m@^\s*(?:\-\-\-\s+a/|\+\+\+\s+b/)@ ||
$line =~ m/^\s*\@\@ \-\d+,\d+ \+\d+,\d+ \@\@/)) {