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Subject[RFC/PATCH RESEND -next 12/21] mm: util: move krealloc/kzfree to slab_common.c
Date
To avoid false positive reports in kernel address sanitizer krealloc/kzfree
functions shouldn't be instrumented. Since we want to instrument other
functions in mm/util.c, krealloc/kzfree moved to slab_common.c which is not
instrumented.

Unfortunately we can't completely disable instrumentation for one function.
We could disable compiler's instrumentation for one function by using
__atribute__((no_sanitize_address)).
But the problem here is that memset call will be replaced by instumented
version kasan_memset since currently it's implemented as define:

Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
---
mm/slab_common.c | 91 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
mm/util.c | 91 --------------------------------------------------------
2 files changed, 91 insertions(+), 91 deletions(-)

diff --git a/mm/slab_common.c b/mm/slab_common.c
index d31c4ba..8df59b09 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -787,3 +787,94 @@ static int __init slab_proc_init(void)
}
module_init(slab_proc_init);
#endif /* CONFIG_SLABINFO */
+
+static __always_inline void *__do_krealloc(const void *p, size_t new_size,
+ gfp_t flags)
+{
+ void *ret;
+ size_t ks = 0;
+
+ if (p)
+ ks = ksize(p);
+
+ if (ks >= new_size)
+ return (void *)p;
+
+ ret = kmalloc_track_caller(new_size, flags);
+ if (ret && p)
+ memcpy(ret, p, ks);
+
+ return ret;
+}
+
+/**
+ * __krealloc - like krealloc() but don't free @p.
+ * @p: object to reallocate memory for.
+ * @new_size: how many bytes of memory are required.
+ * @flags: the type of memory to allocate.
+ *
+ * This function is like krealloc() except it never frees the originally
+ * allocated buffer. Use this if you don't want to free the buffer immediately
+ * like, for example, with RCU.
+ */
+void *__krealloc(const void *p, size_t new_size, gfp_t flags)
+{
+ if (unlikely(!new_size))
+ return ZERO_SIZE_PTR;
+
+ return __do_krealloc(p, new_size, flags);
+
+}
+EXPORT_SYMBOL(__krealloc);
+
+/**
+ * krealloc - reallocate memory. The contents will remain unchanged.
+ * @p: object to reallocate memory for.
+ * @new_size: how many bytes of memory are required.
+ * @flags: the type of memory to allocate.
+ *
+ * The contents of the object pointed to are preserved up to the
+ * lesser of the new and old sizes. If @p is %NULL, krealloc()
+ * behaves exactly like kmalloc(). If @new_size is 0 and @p is not a
+ * %NULL pointer, the object pointed to is freed.
+ */
+void *krealloc(const void *p, size_t new_size, gfp_t flags)
+{
+ void *ret;
+
+ if (unlikely(!new_size)) {
+ kfree(p);
+ return ZERO_SIZE_PTR;
+ }
+
+ ret = __do_krealloc(p, new_size, flags);
+ if (ret && p != ret)
+ kfree(p);
+
+ return ret;
+}
+EXPORT_SYMBOL(krealloc);
+
+/**
+ * kzfree - like kfree but zero memory
+ * @p: object to free memory of
+ *
+ * The memory of the object @p points to is zeroed before freed.
+ * If @p is %NULL, kzfree() does nothing.
+ *
+ * Note: this function zeroes the whole allocated buffer which can be a good
+ * deal bigger than the requested buffer size passed to kmalloc(). So be
+ * careful when using this function in performance sensitive code.
+ */
+void kzfree(const void *p)
+{
+ size_t ks;
+ void *mem = (void *)p;
+
+ if (unlikely(ZERO_OR_NULL_PTR(mem)))
+ return;
+ ks = ksize(mem);
+ memset(mem, 0, ks);
+ kfree(mem);
+}
+EXPORT_SYMBOL(kzfree);
diff --git a/mm/util.c b/mm/util.c
index 8f326ed..2992e16 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -142,97 +142,6 @@ void *memdup_user(const void __user *src, size_t len)
}
EXPORT_SYMBOL(memdup_user);

-static __always_inline void *__do_krealloc(const void *p, size_t new_size,
- gfp_t flags)
-{
- void *ret;
- size_t ks = 0;
-
- if (p)
- ks = ksize(p);
-
- if (ks >= new_size)
- return (void *)p;
-
- ret = kmalloc_track_caller(new_size, flags);
- if (ret && p)
- memcpy(ret, p, ks);
-
- return ret;
-}
-
-/**
- * __krealloc - like krealloc() but don't free @p.
- * @p: object to reallocate memory for.
- * @new_size: how many bytes of memory are required.
- * @flags: the type of memory to allocate.
- *
- * This function is like krealloc() except it never frees the originally
- * allocated buffer. Use this if you don't want to free the buffer immediately
- * like, for example, with RCU.
- */
-void *__krealloc(const void *p, size_t new_size, gfp_t flags)
-{
- if (unlikely(!new_size))
- return ZERO_SIZE_PTR;
-
- return __do_krealloc(p, new_size, flags);
-
-}
-EXPORT_SYMBOL(__krealloc);
-
-/**
- * krealloc - reallocate memory. The contents will remain unchanged.
- * @p: object to reallocate memory for.
- * @new_size: how many bytes of memory are required.
- * @flags: the type of memory to allocate.
- *
- * The contents of the object pointed to are preserved up to the
- * lesser of the new and old sizes. If @p is %NULL, krealloc()
- * behaves exactly like kmalloc(). If @new_size is 0 and @p is not a
- * %NULL pointer, the object pointed to is freed.
- */
-void *krealloc(const void *p, size_t new_size, gfp_t flags)
-{
- void *ret;
-
- if (unlikely(!new_size)) {
- kfree(p);
- return ZERO_SIZE_PTR;
- }
-
- ret = __do_krealloc(p, new_size, flags);
- if (ret && p != ret)
- kfree(p);
-
- return ret;
-}
-EXPORT_SYMBOL(krealloc);
-
-/**
- * kzfree - like kfree but zero memory
- * @p: object to free memory of
- *
- * The memory of the object @p points to is zeroed before freed.
- * If @p is %NULL, kzfree() does nothing.
- *
- * Note: this function zeroes the whole allocated buffer which can be a good
- * deal bigger than the requested buffer size passed to kmalloc(). So be
- * careful when using this function in performance sensitive code.
- */
-void kzfree(const void *p)
-{
- size_t ks;
- void *mem = (void *)p;
-
- if (unlikely(ZERO_OR_NULL_PTR(mem)))
- return;
- ks = ksize(mem);
- memset(mem, 0, ks);
- kfree(mem);
-}
-EXPORT_SYMBOL(kzfree);
-
/*
* strndup_user - duplicate an existing string from user space
* @s: The string to duplicate
--
1.8.5.5


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