linux-kernel - [PATCHv1 1/3] coccinelle: also catch kzfree() issues

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Date:	Mon, 22 Feb 2016 15:09:28 +0100
From:	Yann Droneaud <ydroneaud@...eya.com>
To:	Julia Lawall <julia.lawall@...6.fr>
Cc:	Yann Droneaud <ydroneaud@...eya.com>,
	Gilles Muller <Gilles.Muller@...6.fr>,
	Nicolas Palix <nicolas.palix@...g.fr>,
	Michal Marek <mmarek@...e.com>, Tejun Heo <tj@...nel.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Johannes Weiner <hannes@...xchg.org>, cocci@...teme.lip6.fr,
	linux-kernel@...r.kernel.org
Subject: [PATCHv1 1/3] coccinelle: also catch kzfree() issues

Since commit 3ef0e5ba4673 ('slab: introduce kzfree()'),
kfree() is no more the only function to be considered.

In particular, kzfree() must not be called on memory
allocated through devm_*() functions.

Cc: Johannes Weiner <hannes@...xchg.org>
Signed-off-by: Yann Droneaud <ydroneaud@...eya.com>
---
Hi Julia,

As you suggested, I've use disjunctions instead of regular
expressions (which I managed to use incorrectly: eg.
without ^...$ they catch other functions than kfree(),
such as kfree_skb()).

I've think we should also catch krealloc(, size), where size
is 0, but it's beyond my understanding of coccinelle if size
is not a plain 0 constant.

Perhaps you could help me for this one.

Regards.

 scripts/coccinelle/free/devm_free.cocci |  2 ++
 scripts/coccinelle/free/kfree.cocci     | 18 +++++++++++++++---
 scripts/coccinelle/free/kfreeaddr.cocci |  6 +++++-
 3 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/scripts/coccinelle/free/devm_free.cocci b/scripts/coccinelle/free/devm_free.cocci
index 3d9349012bb3..83c03adec1c5 100644
--- a/scripts/coccinelle/free/devm_free.cocci
+++ b/scripts/coccinelle/free/devm_free.cocci
@@ -48,6 +48,8 @@ position p;
 (
 * kfree@p(x)
 |
+* kzfree@p(x)
+|
 * free_irq@p(x)
 |
 * iounmap@p(x)
diff --git a/scripts/coccinelle/free/kfree.cocci b/scripts/coccinelle/free/kfree.cocci
index 577b78056990..ac438da4fd7b 100644
--- a/scripts/coccinelle/free/kfree.cocci
+++ b/scripts/coccinelle/free/kfree.cocci
@@ -20,7 +20,11 @@ expression E;
 position p1;
 @@
 
-kfree@p1(E)
+(
+* kfree@p1(E)
+|
+* kzfree@p1(E)
+)
 
 @print expression@
 constant char [] c;
@@ -60,7 +64,11 @@ position ok;
 @@
 
 while (1) { ...
-  kfree@ok(E)
+(
+* kfree@ok(E)
+|
+* kzfree@ok(E)
+)
   ... when != break;
       when != goto l;
       when forall
@@ -74,7 +82,11 @@ statement S;
 position free.p1!=loop.ok,p2!={print.p,sz.p};
 @@
 
-kfree@p1(E,...)
+(
+* kfree@p1(E,...)
+|
+* kzfree@p1(E,...)
+)
 ...
 (
  iter(...,subE,...) S // no use
diff --git a/scripts/coccinelle/free/kfreeaddr.cocci b/scripts/coccinelle/free/kfreeaddr.cocci
index ce8aacc314cb..d46063b1db8b 100644
--- a/scripts/coccinelle/free/kfreeaddr.cocci
+++ b/scripts/coccinelle/free/kfreeaddr.cocci
@@ -16,7 +16,11 @@ identifier f;
 position p;
 @@
 
+(
 * kfree@p(&e->f)
+|
+* kzfree@p(&e->f)
+)
 
 @script:python depends on org@
 p << r.p;
@@ -28,5 +32,5 @@ cocci.print_main("kfree",p)
 p << r.p;
 @@
 
-msg = "ERROR: kfree of structure field"
+msg = "ERROR: invalid free of structure field"
 coccilib.report.print_report(p[0],msg)
-- 
2.5.0