From ffe2c748e283c5dc1b9b9ac116299dbfc11a609b Mon Sep 17 00:00:00 2001
From: Catalin Marinas <catalin.marinas@arm.com>
Date: Fri, 6 Jun 2014 14:38:17 -0700
Subject: [PATCH] mm: introduce kmemleak_update_trace()
The memory allocation stack trace is not always useful for debugging a
memory leak (e.g. radix_tree_preload). This function, when called,
updates the stack trace for an already allocated object.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
Documentation/kmemleak.txt | 1 +
include/linux/kmemleak.h | 4 ++++
mm/kmemleak.c | 34 ++++++++++++++++++++++++++++++++++
3 files changed, 39 insertions(+)
diff --git a/Documentation/kmemleak.txt b/Documentation/kmemleak.txt
index a7563ec4ea7bf..b772418bf0648 100644
--- a/Documentation/kmemleak.txt
+++ b/Documentation/kmemleak.txt
@@ -142,6 +142,7 @@ kmemleak_alloc_percpu - notify of a percpu memory block allocation
kmemleak_free - notify of a memory block freeing
kmemleak_free_part - notify of a partial memory block freeing
kmemleak_free_percpu - notify of a percpu memory block freeing
+kmemleak_update_trace - update object allocation stack trace
kmemleak_not_leak - mark an object as not a leak
kmemleak_ignore - do not scan or report an object as leak
kmemleak_scan_area - add scan areas inside a memory block
diff --git a/include/linux/kmemleak.h b/include/linux/kmemleak.h
index 5bb424659c044..057e959710143 100644
--- a/include/linux/kmemleak.h
+++ b/include/linux/kmemleak.h
@@ -30,6 +30,7 @@ extern void kmemleak_alloc_percpu(const void __percpu *ptr, size_t size) __ref;
extern void kmemleak_free(const void *ptr) __ref;
extern void kmemleak_free_part(const void *ptr, size_t size) __ref;
extern void kmemleak_free_percpu(const void __percpu *ptr) __ref;
+extern void kmemleak_update_trace(const void *ptr) __ref;
extern void kmemleak_not_leak(const void *ptr) __ref;
extern void kmemleak_ignore(const void *ptr) __ref;
extern void kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp) __ref;
@@ -83,6 +84,9 @@ static inline void kmemleak_free_recursive(const void *ptr, unsigned long flags)
static inline void kmemleak_free_percpu(const void __percpu *ptr)
{
}
+static inline void kmemleak_update_trace(const void *ptr)
+{
+}
static inline void kmemleak_not_leak(const void *ptr)
{
}
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 5d4aec44982e5..3cda50c1e3942 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -989,6 +989,40 @@ void __ref kmemleak_free_percpu(const void __percpu *ptr)
}
EXPORT_SYMBOL_GPL(kmemleak_free_percpu);
+/**
+ * kmemleak_update_trace - update object allocation stack trace
+ * @ptr: pointer to beginning of the object
+ *
+ * Override the object allocation stack trace for cases where the actual
+ * allocation place is not always useful.
+ */
+void __ref kmemleak_update_trace(const void *ptr)
+{
+ struct kmemleak_object *object;
+ unsigned long flags;
+
+ pr_debug("%s(0x%p)\n", __func__, ptr);
+
+ if (!kmemleak_enabled || IS_ERR_OR_NULL(ptr))
+ return;
+
+ object = find_and_get_object((unsigned long)ptr, 1);
+ if (!object) {
+#ifdef DEBUG
+ kmemleak_warn("Updating stack trace for unknown object at %p\n",
+ ptr);
+#endif
+ return;
+ }
+
+ spin_lock_irqsave(&object->lock, flags);
+ object->trace_len = __save_stack_trace(object->trace);
+ spin_unlock_irqrestore(&object->lock, flags);
+
+ put_object(object);
+}
+EXPORT_SYMBOL(kmemleak_update_trace);
+
/**
* kmemleak_not_leak - mark an allocated object as false positive
* @ptr: pointer to beginning of the object
--
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