[cocci] [PATCH v3 2/2] coccinelle: locks: add missing_spin_lock_init.cocci script

[Yuan Can <yuancan@huawei.com>]

Find spin lock inside struct which is possibly used without init,
provide the name of the struct and of the spin lock, the position
where the struct is malloced and where the spin lock get locked.

Signed-off-by: Yuan Can <yuancan@huawei.com>
---
 .../locks/missing_spin_lock_init.cocci        | 79 +++++++++++++++++++
 1 file changed, 79 insertions(+)
 create mode 100644 scripts/coccinelle/locks/missing_spin_lock_init.cocci

diff --git a/scripts/coccinelle/locks/missing_spin_lock_init.cocci b/scripts/coccinelle/locks/missing_spin_lock_init.cocci
new file mode 100644
index 000000000000..9724d348e28e
--- /dev/null
+++ b/scripts/coccinelle/locks/missing_spin_lock_init.cocci
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/// report missing spin_lock_init()
+///
+/// Report spin lock used without initialize. False positives
+/// can occur when the spin lock allocation and initialization
+/// happens in two different files.
+///
+// Confidence: Low
+// Copyright: (C) 2022 Huawei Technologies Co, Ltd.
+// Comments:
+// Options: --include-headers
+
+virtual org
+virtual report
+
+@r1@
+identifier s, fld;
+struct s *mm;
+@@
+  spin_lock_init(&(mm->fld))
+
+@r2@
+identifier r1.s, r1.fld;
+position p;
+@@
+
+struct s {
+  ...
+  spinlock_t fld@p;
+  ...
+};
+
+@r3@
+identifier s, fld;
+position p != {r2.p};
+@@
+
+struct s {
+  ...
+  spinlock_t fld@p;
+  ...
+};
+
+@r4@
+identifier r3.fld;
+identifier r3.s;
+struct s *mm;
+position p;
+@@
+(
+ \(spin_lock\|spin_lock_bh\|spin_trylock\|spin_lock_irq\)(&mm->fld@p)
+|
+ spin_lock_irqsave(&mm->fld@p,...)
+)
+
+@r5 depends on r4@
+identifier r3.s;
+struct s *mm;
+position p;
+@@
+mm@p = \(kmalloc\|kzalloc\|devm_kmalloc\|devm_kzalloc\)(...)
+
+@script:python depends on org@
+p << r5.p;
+p1 << r4.p;
+s << r3.s;
+fld << r3.fld;
+@@
+msg = "Spin lock %s inside the struct %s malloced at line %s is possibly used at line %s without init." % (fld, s, p[0].line, p1[0].line);
+cocci.print_main(msg, p)
+
+@script:python depends on report@
+p << r5.p;
+p1 << r4.p;
+s << r3.s;
+fld << r3.fld;
+@@
+msg = "Spin lock %s inside the struct %s malloced at line %s is possibly used at line %s without init." % (fld, s, p[0].line, p1[0].line);
+coccilib.report.print_report(p[0], msg)
-- 
2.17.1