[PATCH] coccinelle: api: add kzfree script

[Denis Efremov]

Check for memset() with 0 followed by kfree().

Signed-off-by: Denis Efremov <efremov@xxxxxxxxx>
---
Patches:
1. kzfree in drivers/w1 https://lkml.org/lkml/2020/6/4/438
2. kzfree in drivers/iommu/ https://lkml.org/lkml/2020/6/4/421
3. kzfree in drivers/scsi/ https://lkml.org/lkml/2020/6/4/442

 scripts/coccinelle/api/kzfree.cocci | 53 +++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)
 create mode 100644 scripts/coccinelle/api/kzfree.cocci

diff --git a/scripts/coccinelle/api/kzfree.cocci b/scripts/coccinelle/api/kzfree.cocci
new file mode 100644
index 000000000000..c6b8f7676af4
--- /dev/null
+++ b/scripts/coccinelle/api/kzfree.cocci
@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: GPL-2.0-only
+///
+/// Use kzfree rather than memset with 0 followed by kfree
+///
+// Confidence: High
+// Copyright: (C) 2020 Denis Efremov ISPRAS
+// Options: --no-includes --include-headers
+//
+// Keywords: kzfree
+//
+
+virtual context
+virtual org
+virtual report
+virtual patch
+
+// Ignore kzfree definition
+// Ignore kasan test
+@r depends on !patch && !(file in "lib/test_kasan.c") && !(file in "mm/slab_common.c")@
+expression E;
+position p;
+@@
+
+(
+* memset(E, 0, ...);
+|
+* memset(E, '\0', ...);
+)
+* kfree(E)@p;
+
+@r1 depends on patch && !(file in "lib/test_kasan.c") && !(file in "mm/slab_common.c")@
+expression E;
+@@
+
+(
+- memset(E, 0, ...);
+|
+- memset(E, '\0', ...);
+)
+- kfree(E);
++ kzfree(E);
+
+@script:python depends on report@
+p << r.p;
+@@
+
+coccilib.report.print_report(p[0], "WARNING opportunity for kzfree")
+
+@script:python depends on org@
+p << r.p;
+@@
+
+coccilib.org.print_todo(p[0], "WARNING opportunity for kzfree")
-- 
2.26.2