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authorJoe Perches <joe@perches.com>2020-10-16 06:12:09 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-10-16 21:11:21 +0300
commit99ca38c2aa7da5ab39e55f13fd425c6101903ccb (patch)
tree2f209a09fbe8a7a1dc9a5dfe461b565476df9fa0
parentc12093a11462b775a83ed600bf0036c8bef3e841 (diff)
downloadlinux-99ca38c2aa7da5ab39e55f13fd425c6101903ccb.tar.xz
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 <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Kees Cook <keescook@chromium.org> Cc: Gustavo A. R. Silva <gustavoars@kernel.org> Cc: Denis Efremov <efremov@linux.com> Cc: Julia Lawall <julia.lawall@inria.fr> Link: https://lkml.kernel.org/r/afc2cffdd315d3e4394af149278df9e8af7f49f4.camel@perches.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rwxr-xr-xscripts/checkpatch.pl11
1 files changed, 11 insertions, 0 deletions
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/) {