[Cocci] [PATCH v5] coccinelle: api: add kvfree script

[Denis Efremov <efremov@linux.com>]

Check that alloc and free types of functions match each other.

Signed-off-by: Denis Efremov <efremov@linux.com>
---
Changes in v2:
 - Lines are limited to 80 characters where possible
 - Confidence changed from High to Medium because of 
   fs/btrfs/send.c:1119 false-positive
 - __vmalloc_area_node() explicitly excluded from analysis
   instead of !(file in "mm/vmalloc.c") condition
Changes in v3:
 - prints style in org && report modes changed for python2
Changes in v4:
 - missing msg argument to print_todo fixed
Changes in v5:
 - fix position p in kfree rule
 - move @kok and @v positions in choice rule after the arguments
 - remove kvmalloc suggestions

 scripts/coccinelle/api/kvfree.cocci | 182 ++++++++++++++++++++++++++++
 1 file changed, 182 insertions(+)
 create mode 100644 scripts/coccinelle/api/kvfree.cocci

diff --git a/scripts/coccinelle/api/kvfree.cocci b/scripts/coccinelle/api/kvfree.cocci
new file mode 100644
index 000000000000..e83b1ebbad7e
--- /dev/null
+++ b/scripts/coccinelle/api/kvfree.cocci
@@ -0,0 +1,182 @@
+// SPDX-License-Identifier: GPL-2.0-only
+///
+/// Check that kvmalloc'ed memory is freed by kfree functions,
+/// vmalloc'ed by vfree functions and kvmalloc'ed by kvfree
+/// functions.
+///
+// Confidence: Medium
+// Copyright: (C) 2020 Denis Efremov ISPRAS
+// Options: --no-includes --include-headers
+//
+
+virtual patch
+virtual report
+virtual org
+virtual context
+
+@initialize:python@
+@@
+# low-level memory api
+filter = frozenset(['__vmalloc_area_node'])
+
+def relevant(p):
+    return not (filter & {el.current_element for el in p})
+
+@choice@
+expression E, E1;
+position kok, vok;
+@@
+
+(
+  if (...) {
+    ...
+    E = \(kmalloc\|kzalloc\|krealloc\|kcalloc\|
+          kmalloc_node\|kzalloc_node\|kmalloc_array\|
+          kmalloc_array_node\|kcalloc_node\)(...)@kok
+    ...
+  } else {
+    ...
+    E = \(vmalloc\|vzalloc\|vmalloc_user\|vmalloc_node\|
+          vzalloc_node\|vmalloc_exec\|vmalloc_32\|
+          vmalloc_32_user\|__vmalloc\|__vmalloc_node_range\|
+          __vmalloc_node\)(...)@vok
+    ...
+  }
+|
+  E = \(kmalloc\|kzalloc\|krealloc\|kcalloc\|kmalloc_node\|kzalloc_node\|
+        kmalloc_array\|kmalloc_array_node\|kcalloc_node\)(...)
+  ... when != E = E1
+      when any
+  if (\(!E\|E == NULL\)) {
+    ...
+    E = \(vmalloc\|vzalloc\|vmalloc_user\|vmalloc_node\|
+          vzalloc_node\|vmalloc_exec\|vmalloc_32\|
+          vmalloc_32_user\|__vmalloc\|__vmalloc_node_range\|
+          __vmalloc_node\)(...)@vok
+    ...
+  }
+)
+
+@vfree depends on !patch@
+expression E;
+position k != choice.kok;
+position p;
+@@
+
+* E = \(kmalloc\|kzalloc\|krealloc\|kcalloc\|kmalloc_node\|
+        kzalloc_node\|kmalloc_array\|kmalloc_array_node\|
+        kcalloc_node\)(...)@k
+  ... when != if (...) { ... E = \(vmalloc\|vzalloc\|vmalloc_user\|vmalloc_node\|vzalloc_node\|vmalloc_exec\|vmalloc_32\|vmalloc_32_user\|__vmalloc\|__vmalloc_node_range\|__vmalloc_node\)(...); ... }
+      when != is_vmalloc_addr(E)
+      when any
+* \(vfree\|vfree_atomic\|kvfree\)(E)@p
+
+@pvfree depends on patch exists@
+expression E;
+position k != choice.kok;
+@@
+
+  E = \(kmalloc\|kzalloc\|krealloc\|kcalloc\|kmalloc_node\|
+        kzalloc_node\|kmalloc_array\|kmalloc_array_node\|
+        kcalloc_node\)(...)@k
+  ... when != if (...) { ... E = \(vmalloc\|vzalloc\|vmalloc_user\|vmalloc_node\|vzalloc_node\|vmalloc_exec\|vmalloc_32\|vmalloc_32_user\|__vmalloc\|__vmalloc_node_range\|__vmalloc_node\)(...); ... }
+      when != is_vmalloc_addr(E)
+      when any
+- \(vfree\|vfree_atomic\|kvfree\)(E)
++ kfree(E)
+
+@kfree depends on !patch@
+expression E;
+position v != choice.vok;
+position p;
+@@
+
+* E = \(vmalloc\|vzalloc\|vmalloc_user\|vmalloc_node\|vzalloc_node\|
+        vmalloc_exec\|vmalloc_32\|vmalloc_32_user\|__vmalloc\|
+        __vmalloc_node_range\|__vmalloc_node\)(...)@v
+  ... when != !is_vmalloc_addr(E)
+      when any
+* \(kfree\|kzfree\|kvfree\)(E)@p
+
+@pkfree depends on patch exists@
+expression E;
+position v != choice.vok;
+@@
+
+  E = \(vmalloc\|vzalloc\|vmalloc_user\|vmalloc_node\|vzalloc_node\|
+        vmalloc_exec\|vmalloc_32\|vmalloc_32_user\|__vmalloc\|
+        __vmalloc_node_range\|__vmalloc_node\)(...)@v
+  ... when != !is_vmalloc_addr(E)
+      when any
+- \(kfree\|kvfree\)(E)
++ vfree(E)
+
+@kvfree depends on !patch@
+expression E;
+position p, k;
+@@
+
+* E = \(kvmalloc\|kvzalloc\|kvcalloc\|kvzalloc_node\|kvmalloc_node\|
+        kvmalloc_array\)(...)@k
+  ... when != is_vmalloc_addr(E)
+      when any
+* \(kfree\|kzfree\|vfree\|vfree_atomic\)(E)@p
+
+@pkvfree depends on patch exists@
+expression E;
+@@
+
+  E = \(kvmalloc\|kvzalloc\|kvcalloc\|kvzalloc_node\|kvmalloc_node\|
+        kvmalloc_array\)(...)
+  ... when != is_vmalloc_addr(E)
+      when any
+- \(kfree\|vfree\)(E)
++ kvfree(E)
+
+@script: python depends on report@
+k << vfree.k;
+p << vfree.p;
+@@
+
+msg = "WARNING: kmalloc is used to allocate this memory at line %s" % (k[0].line)
+coccilib.report.print_report(p[0], msg)
+
+@script: python depends on org@
+k << vfree.k;
+p << vfree.p;
+@@
+
+msg = "WARNING: kmalloc is used to allocate this memory at line %s" % (k[0].line)
+coccilib.org.print_todo(p[0], msg)
+
+@script: python depends on report@
+v << kfree.v;
+p << kfree.p;
+@@
+
+msg = "WARNING: vmalloc is used to allocate this memory at line %s" % (v[0].line)
+coccilib.report.print_report(p[0], msg)
+
+@script: python depends on org@
+v << kfree.v;
+p << kfree.p;
+@@
+
+msg = "WARNING: vmalloc is used to allocate this memory at line %s" % (v[0].line)
+coccilib.org.print_todo(p[0], msg)
+
+@script: python depends on report@
+k << kvfree.k;
+p << kvfree.p;
+@@
+
+msg = "WARNING: kvmalloc is used to allocate this memory at line %s" % (k[0].line)
+coccilib.report.print_report(p[0], msg)
+
+@script: python depends on org@
+k << kvfree.k;
+p << kvfree.p;
+@@
+
+msg = "WARNING: kvmalloc is used to allocate this memory at line %s" % (k[0].line)
+coccilib.org.print_todo(p[0], msg)
-- 
2.26.2

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