From 99ca38c2aa7da5ab39e55f13fd425c6101903ccb Mon Sep 17 00:00:00 2001 From: Joe Perches Date: Thu, 15 Oct 2020 20:12:09 -0700 Subject: checkpatch: warn on self-assignments The uninitialized_var() macro was removed recently via commit 63a0895d960a ("compiler: Remove uninitialized_var() macro") as it's not a particularly useful warning and its use can "paper over real bugs". Add a checkpatch test to warn on self-assignments as a means to avoid compiler warnings and as a back-door mechanism to reproduce the old uninitialized_var macro behavior. [akpm@linux-foundation.org: coding style fixes] Signed-off-by: Joe Perches Signed-off-by: Andrew Morton Cc: Kees Cook Cc: Gustavo A. R. Silva Cc: Denis Efremov Cc: Julia Lawall Link: https://lkml.kernel.org/r/afc2cffdd315d3e4394af149278df9e8af7f49f4.camel@perches.com Signed-off-by: Linus Torvalds --- scripts/checkpatch.pl | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'scripts') diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index 81c20557d974..5fe8762b1fae 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -3899,6 +3899,17 @@ sub process { #ignore lines not being added next if ($line =~ /^[^\+]/); +# check for self assignments used to avoid compiler warnings +# e.g.: int foo = foo, *bar = NULL; +# struct foo bar = *(&(bar)); + if ($line =~ /^\+\s*(?:$Declare)?([A-Za-z_][A-Za-z\d_]*)\s*=/) { + my $var = $1; + if ($line =~ /^\+\s*(?:$Declare)?$var\s*=\s*(?:$var|\*\s*\(?\s*&\s*\(?\s*$var\s*\)?\s*\)?)\s*[;,]/) { + WARN("SELF_ASSIGNMENT", + "Do not use self-assignments to avoid compiler warnings\n" . $herecurr); + } + } + # check for dereferences that span multiple lines if ($prevline =~ /^\+.*$Lval\s*(?:\.|->)\s*$/ && $line =~ /^\+\s*(?!\#\s*(?!define\s+|if))\s*$Lval/) { -- cgit v1.2.3-70-g09d2