Commit 99ca38c2 authored by Joe Perches's avatar Joe Perches Committed by Linus Torvalds
Browse files

checkpatch: warn on self-assignments 



The uninitialized_var() macro was removed recently via commit 63a0895d
("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: default avatarJoe Perches <joe@perches.com>
Signed-off-by: default avatarAndrew 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: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c12093a1

scripts/checkpatch.pl

+11 −0
Original line number Diff line number Diff line
@@ -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/) {