From: Mrinal Pandey mrinalmni@gmail.com
commit 13e45417cedbfc44b1926124b1846f5ee8c6ba4a upstream.
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/checkpatch.pl 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, `$1` can be initialized to the text that capture group matches thereby setting it to the desired and required value.
Fixes: e518e9a59ec3 ("checkpatch: emit an error when there's a diff in a changelog") Signed-off-by: Mrinal Pandey mrinalmni@gmail.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Tested-by: Lukas Bulwahn lukas.bulwahn@gmail.com Reviewed-by: Lukas Bulwahn lukas.bulwahn@gmail.com Cc: Joe Perches joe@perches.com Link: https://lkml.kernel.org/r/20200714032352.f476hanaj2dlmiot@mrinalpandey Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- scripts/checkpatch.pl | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -2636,8 +2636,8 @@ sub process {
# Check if the commit log has what seems like a diff which can confuse patch if ($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+ @@/)) { ERROR("DIFF_IN_COMMIT_MSG",