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

From: Yann Droneaud
Date: Mon Feb 22 2016 - 09:09:46 EST


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@xxxxxxxxxxx>
Signed-off-by: Yann Droneaud <ydroneaud@xxxxxxxxxx>
---
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