[PATCH] D76917: [analyzer][MallocChecker] Fix that kfree only takes a single argument

[Kristóf Umann via Phabricator via cfe-commits]

Szelethus created this revision.
Szelethus added reviewers: balazske, NoQ, martong, baloghadamsoftware.
Szelethus added a project: clang.
Herald added subscribers: cfe-commits, ASDenysPetrov, steakhal, Charusso, gamesh411, dkrupp, donat.nagy, mikhail.ramalho, a.sidorin, rnkovacs, szepet, xazax.hun, whisperity.

Exactly what it says on the tin!

https://www.kernel.org/doc/htmldocs/kernel-api/API-kfree.html


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D76917

Files:
  clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp
  clang/test/Analysis/kmalloc-linux.c


Index: clang/test/Analysis/kmalloc-linux.c
===================================================================
--- clang/test/Analysis/kmalloc-linux.c
+++ clang/test/Analysis/kmalloc-linux.c
@@ -1,4 +1,7 @@
-// RUN: %clang_analyze_cc1 -triple x86_64-unknown-linux %s
+// RUN: %clang_analyze_cc1 -triple x86_64-unknown-linux %s -verify \
+// RUN:   -Wno-incompatible-library-redeclaration \
+// RUN:   -analyzer-checker=core \
+// RUN:   -analyzer-checker=unix.Malloc
 
 #define __GFP_ZERO 0x8000
 #define NULL ((void *)0)
@@ -6,6 +9,7 @@
 typedef __typeof(sizeof(int)) size_t;
 
 void *kmalloc(size_t, int);
+void kfree(void *);
 
 struct test {
 };
@@ -61,6 +65,8 @@
 
 struct malloc_type;
 
+// 3 parameter malloc:
+// https://www.freebsd.org/cgi/man.cgi?query=malloc&sektion=9
 void *malloc(unsigned long size, struct malloc_type *mtp, int flags);
 
 void test_3arg_malloc(struct malloc_type *mtp) {
@@ -97,7 +103,7 @@
   struct test **list, *t;
   int i;
 
-  list = alloc(sizeof(*list) * 10, mtp, flags);
+  list = malloc(sizeof(*list) * 10, mtp, flags);
   if (list == NULL)
     return;
 
@@ -107,3 +113,11 @@
   }
   kfree(list);
 }
+
+void test_3arg_malloc_leak(struct malloc_type *mtp, int flags) {
+  struct test **list;
+
+  list = malloc(sizeof(*list) * 10, mtp, flags);
+  if (list == NULL)
+    return;
+} // expected-warning{{Potential leak of memory pointed to by 'list'}}
Index: clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp
+++ clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp
@@ -285,7 +285,7 @@
       CD_strdup{{"strdup"}, 1}, CD_win_strdup{{"_strdup"}, 1},
       CD_kmalloc{{"kmalloc"}, 2}, CD_if_nameindex{{"if_nameindex"}, 1},
       CD_if_freenameindex{{"if_freenameindex"}, 1}, CD_wcsdup{{"wcsdup"}, 1},
-      CD_win_wcsdup{{"_wcsdup"}, 1}, CD_kfree{{"kfree"}, 2},
+      CD_win_wcsdup{{"_wcsdup"}, 1}, CD_kfree{{"kfree"}, 1},
       CD_g_malloc{{"g_malloc"}, 1}, CD_g_malloc0{{"g_malloc0"}, 1},
       CD_g_realloc{{"g_realloc"}, 2}, CD_g_try_malloc{{"g_try_malloc"}, 1},
       CD_g_try_malloc0{{"g_try_malloc0"}, 1},


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