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checkpatch: warn on self-assignments 

The uninitialized_var() macro was removed recently via commit 63a0895d96
("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>
This commit is contained in:
Joe Perches 2020-10-15 20:12:09 -07:00 committed by Linus Torvalds
parent c12093a114
commit 99ca38c2aa
1 changed files with 11 additions and 0 deletions
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11
scripts/checkpatch.pl
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@ -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/) {