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Subject: [PATCH] scripts/checkpatch.pl: Add WARN on sizeof(&
From: Joe Perches <joe@perches.com>
To: Andy Whitcroft <apw@canonical.com>
Cc: Jan Ceuleers <jan.ceuleers@computer.org>,
       David Miller <davem@davemloft.net>, LKML <linux-kernel@vger.kernel.org>
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References: <20091002113038.1dc3d284@hyperion.delvare>
	 <20091002.095402.42770342.davem@davemloft.net>
	 <4AC77003.9090805@computer.org>
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Date: Sat, 03 Oct 2009 18:12:49 -0700
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On Sat, 2009-10-03 at 17:38 +0200, Jan Ceuleers wrote:
> David Miller wrote:
> > Any time you see "&" in a sizeof() expression, it's almost
> > certainly a bug.  Something for the folks with automated
> > tools to look for if they haven't already :-)
> 
> Your remark prompted me to find four more instances of such bugs
> (none of which in the networking bits). I have submitted patches.

Perhaps a checkpatch test.

---

sizeof(&foo) is frequently an error.  Warn on its use.

Signed-off-by: Joe Perches <joe@perches.com>

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 87bbb8b..596dd72 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2534,6 +2534,11 @@ sub process {
 			WARN("plain inline is preferred over $1\n" . $herecurr);
 		}
 
+# check for sizeof(&)
+		if ($line =~ /\bsizeof\s*\(\s*\&/) {
+			WARN("sizeof(& should be avoided\n" . $herecurr);
+		}
+
 # check for new externs in .c files.
 		if ($realfile =~ /\.c$/ && defined $stat &&
 		    $stat =~ /^.\s*(?:extern\s+)?$Type\s+($Ident)(\s*)\(/s)