diff mbox

[RFC/PATCH,RESEND,-next,12/21] mm: util: move krealloc/kzfree to slab_common.c

Message ID 1404905415-9046-13-git-send-email-a.ryabinin@samsung.com (mailing list archive)
State New, archived
Headers show

Commit Message

Andrey Ryabinin July 9, 2014, 11:30 a.m. UTC
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(-)

Comments

Christoph Lameter (Ampere) July 9, 2014, 2:32 p.m. UTC | #1
On Wed, 9 Jul 2014, Andrey Ryabinin wrote:

> 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:

Looks good to me and useful regardless of the sanitizer going in.

Acked-by: Christoph Lameter <cl@linux.com>
Andrey Ryabinin July 10, 2014, 7:43 a.m. UTC | #2
On 07/09/14 18:32, Christoph Lameter wrote:
> On Wed, 9 Jul 2014, Andrey Ryabinin wrote:
> 
>> 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:
> 
> Looks good to me and useful regardless of the sanitizer going in.
> 
> Acked-by: Christoph Lameter <cl@linux.com>
> 

I also noticed in mm/util.c:

	/* Tracepoints definitions. */
	EXPORT_TRACEPOINT_SYMBOL(kmalloc);
	EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
	EXPORT_TRACEPOINT_SYMBOL(kmalloc_node);
	EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node);
	EXPORT_TRACEPOINT_SYMBOL(kfree);
	EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);

Should I send another patch to move this to slab_common.c?
Christoph Lameter (Ampere) July 10, 2014, 2:08 p.m. UTC | #3
On Thu, 10 Jul 2014, Andrey Ryabinin wrote:

> Should I send another patch to move this to slab_common.c?

Send one patch that is separte from this patchset to all slab
maintainers and include my ack.
diff mbox

Patch

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