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* [RFC PATCH 1/3] selftests: add rbtree selftests
@ 2019-12-24 12:12 Heiher
  2019-12-24 12:12 ` [RFC PATCH 2/3] lib/rbtree: fix null pointer dereference in erase Heiher
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Heiher @ 2019-12-24 12:12 UTC (permalink / raw)
  To: linux-kernel; +Cc: Heiher, Andrew Morton, Michel Lespinasse, Peter Zijlstra

This adds the selftest for rbtree. It will reproduce the crash at earsing.

Signed-off-by: hev <r@hev.cc>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michel Lespinasse <walken@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
---
 tools/testing/selftests/Makefile              |  1 +
 tools/testing/selftests/lib/rbtree/.gitignore |  1 +
 tools/testing/selftests/lib/rbtree/Makefile   | 29 ++++++++
 .../selftests/lib/rbtree/rbtree_test.c        | 70 +++++++++++++++++++
 4 files changed, 101 insertions(+)
 create mode 100644 tools/testing/selftests/lib/rbtree/.gitignore
 create mode 100644 tools/testing/selftests/lib/rbtree/Makefile
 create mode 100644 tools/testing/selftests/lib/rbtree/rbtree_test.c

diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index b001c602414b..0e84ca3f207f 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -25,6 +25,7 @@ TARGETS += kcmp
 TARGETS += kexec
 TARGETS += kvm
 TARGETS += lib
+TARGETS += lib/rbtree
 TARGETS += livepatch
 TARGETS += membarrier
 TARGETS += memfd
diff --git a/tools/testing/selftests/lib/rbtree/.gitignore b/tools/testing/selftests/lib/rbtree/.gitignore
new file mode 100644
index 000000000000..4c9f82761fad
--- /dev/null
+++ b/tools/testing/selftests/lib/rbtree/.gitignore
@@ -0,0 +1 @@
+rbtree_test
diff --git a/tools/testing/selftests/lib/rbtree/Makefile b/tools/testing/selftests/lib/rbtree/Makefile
new file mode 100644
index 000000000000..68fa9dad24a1
--- /dev/null
+++ b/tools/testing/selftests/lib/rbtree/Makefile
@@ -0,0 +1,29 @@
+# SPDX-License-Identifier: GPL-2.0
+
+CFLAGS += -I../../../../include/
+
+include ../../lib.mk
+
+# lib.mk TEST_CUSTOM_PROGS var is for custom tests that need special
+# build rules. lib.mk will run and install them.
+
+TEST_CUSTOM_PROGS := $(OUTPUT)/rbtree_test
+all: $(TEST_CUSTOM_PROGS)
+
+OBJS = rbtree_test.o
+
+LIBS = ../../../../lib/rbtree.o
+
+OBJS := $(patsubst %,$(OUTPUT)/%,$(OBJS))
+LIBS := $(patsubst %,$(OUTPUT)/%,$(LIBS))
+
+$(TEST_CUSTOM_PROGS): $(LIBS) $(OBJS)
+	$(CC) -o $(TEST_CUSTOM_PROGS) $(OBJS) $(LIBS) $(CFLAGS) $(LDFLAGS)
+
+$(OBJS): $(OUTPUT)/%.o: %.c
+	$(CC) -c $^ -o $@ $(CFLAGS)
+
+$(LIBS): $(OUTPUT)/%.o: %.c
+	$(CC) -c $^ -o $@ $(CFLAGS)
+
+EXTRA_CLEAN := $(TEST_CUSTOM_PROGS) $(OBJS) $(LIBS)
diff --git a/tools/testing/selftests/lib/rbtree/rbtree_test.c b/tools/testing/selftests/lib/rbtree/rbtree_test.c
new file mode 100644
index 000000000000..11420541071a
--- /dev/null
+++ b/tools/testing/selftests/lib/rbtree/rbtree_test.c
@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <stdlib.h>
+#include <linux/rbtree.h>
+#include "../../kselftest_harness.h"
+
+struct node {
+	struct rb_node node;
+	int key;
+};
+
+static int _insert(struct rb_root *tree, int key)
+{
+	struct rb_node **new = &tree->rb_node, *parent = NULL;
+	struct node *node;
+
+	while (*new) {
+		struct node *this = container_of(*new, struct node, node);
+
+		if (key < this->key)
+			new = &((*new)->rb_left);
+		else if (key > this->key)
+			new = &((*new)->rb_right);
+		else
+			return 0;
+	}
+
+	node = malloc(sizeof(struct node));
+	if (!node)
+		return 0;
+
+	node->key = key;
+	rb_link_node(&node->node, parent, new);
+	rb_insert_color(&node->node, tree);
+
+	return 1;
+}
+
+static void _remove(struct rb_root *tree, int key)
+{
+	struct rb_node **node = &tree->rb_node;
+
+	while (*node) {
+		struct node *this = container_of(*node, struct node, node);
+
+		if (key < this->key) {
+			node = &((*node)->rb_left);
+		} else if (key > this->key) {
+			node = &((*node)->rb_right);
+		} else {
+			rb_erase(&this->node, tree);
+			free(this);
+			return;
+		}
+	}
+}
+
+TEST(rbtree)
+{
+	struct rb_root tree = { 0 };
+
+	_insert(&tree, 2);
+	_insert(&tree, 1);
+	_insert(&tree, 4);
+	_insert(&tree, 3);
+
+	_remove(&tree, 2);
+}
+
+TEST_HARNESS_MAIN
-- 
2.24.1


^ permalink raw reply related	[flat|nested] 4+ messages in thread

* [RFC PATCH 2/3] lib/rbtree: fix null pointer dereference in erase
  2019-12-24 12:12 [RFC PATCH 1/3] selftests: add rbtree selftests Heiher
@ 2019-12-24 12:12 ` Heiher
  2019-12-24 12:12 ` [RFC PATCH 3/3] tools/rbtree: " Heiher
  2019-12-24 17:00 ` [RFC PATCH 1/3] selftests: add rbtree selftests Hev
  2 siblings, 0 replies; 4+ messages in thread
From: Heiher @ 2019-12-24 12:12 UTC (permalink / raw)
  To: linux-kernel; +Cc: Heiher, Andrew Morton, Michel Lespinasse, Peter Zijlstra

a null pointer dereference in erasing the root node of below tree.

Tree structure:
		   (1)[2]
		  /   \
	       (2)[1]  (3)[4]
		      /
		   (4)[3]

(n): Insert order
[n]: Key value or key order

Signed-off-by: hev <r@hev.cc>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michel Lespinasse <walken@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
---
 lib/rbtree.c | 94 +++++++++++++++++++++++++++-------------------------
 1 file changed, 48 insertions(+), 46 deletions(-)

diff --git a/lib/rbtree.c b/lib/rbtree.c
index abc86c6a3177..a710c21f7be6 100644
--- a/lib/rbtree.c
+++ b/lib/rbtree.c
@@ -351,56 +351,58 @@ ____rb_erase_color(struct rb_node *parent, struct rb_root *root,
 			break;
 		} else {
 			sibling = parent->rb_left;
-			if (rb_is_red(sibling)) {
-				/* Case 1 - right rotate at parent */
-				tmp1 = sibling->rb_right;
-				WRITE_ONCE(parent->rb_left, tmp1);
-				WRITE_ONCE(sibling->rb_right, parent);
-				rb_set_parent_color(tmp1, parent, RB_BLACK);
-				__rb_rotate_set_parents(parent, sibling, root,
-							RB_RED);
-				augment_rotate(parent, sibling);
-				sibling = tmp1;
-			}
-			tmp1 = sibling->rb_left;
-			if (!tmp1 || rb_is_black(tmp1)) {
-				tmp2 = sibling->rb_right;
-				if (!tmp2 || rb_is_black(tmp2)) {
-					/* Case 2 - sibling color flip */
-					rb_set_parent_color(sibling, parent,
-							    RB_RED);
-					if (rb_is_red(parent))
-						rb_set_black(parent);
-					else {
-						node = parent;
-						parent = rb_parent(node);
-						if (parent)
-							continue;
+			if (sibling) {
+				if (rb_is_red(sibling)) {
+					/* Case 1 - right rotate at parent */
+					tmp1 = sibling->rb_right;
+					WRITE_ONCE(parent->rb_left, tmp1);
+					WRITE_ONCE(sibling->rb_right, parent);
+					rb_set_parent_color(tmp1, parent, RB_BLACK);
+					__rb_rotate_set_parents(parent, sibling, root,
+								RB_RED);
+					augment_rotate(parent, sibling);
+					sibling = tmp1;
+				}
+				tmp1 = sibling->rb_left;
+				if (!tmp1 || rb_is_black(tmp1)) {
+					tmp2 = sibling->rb_right;
+					if (!tmp2 || rb_is_black(tmp2)) {
+						/* Case 2 - sibling color flip */
+						rb_set_parent_color(sibling, parent,
+									RB_RED);
+						if (rb_is_red(parent))
+							rb_set_black(parent);
+						else {
+							node = parent;
+							parent = rb_parent(node);
+							if (parent)
+								continue;
+						}
+						break;
 					}
-					break;
+					/* Case 3 - left rotate at sibling */
+					tmp1 = tmp2->rb_left;
+					WRITE_ONCE(sibling->rb_right, tmp1);
+					WRITE_ONCE(tmp2->rb_left, sibling);
+					WRITE_ONCE(parent->rb_left, tmp2);
+					if (tmp1)
+						rb_set_parent_color(tmp1, sibling,
+									RB_BLACK);
+					augment_rotate(sibling, tmp2);
+					tmp1 = sibling;
+					sibling = tmp2;
 				}
-				/* Case 3 - left rotate at sibling */
-				tmp1 = tmp2->rb_left;
-				WRITE_ONCE(sibling->rb_right, tmp1);
-				WRITE_ONCE(tmp2->rb_left, sibling);
+				/* Case 4 - right rotate at parent + color flips */
+				tmp2 = sibling->rb_right;
 				WRITE_ONCE(parent->rb_left, tmp2);
-				if (tmp1)
-					rb_set_parent_color(tmp1, sibling,
-							    RB_BLACK);
-				augment_rotate(sibling, tmp2);
-				tmp1 = sibling;
-				sibling = tmp2;
+				WRITE_ONCE(sibling->rb_right, parent);
+				rb_set_parent_color(tmp1, sibling, RB_BLACK);
+				if (tmp2)
+					rb_set_parent(tmp2, parent);
+				__rb_rotate_set_parents(parent, sibling, root,
+							RB_BLACK);
+				augment_rotate(parent, sibling);
 			}
-			/* Case 4 - right rotate at parent + color flips */
-			tmp2 = sibling->rb_right;
-			WRITE_ONCE(parent->rb_left, tmp2);
-			WRITE_ONCE(sibling->rb_right, parent);
-			rb_set_parent_color(tmp1, sibling, RB_BLACK);
-			if (tmp2)
-				rb_set_parent(tmp2, parent);
-			__rb_rotate_set_parents(parent, sibling, root,
-						RB_BLACK);
-			augment_rotate(parent, sibling);
 			break;
 		}
 	}
-- 
2.24.1


^ permalink raw reply related	[flat|nested] 4+ messages in thread

* [RFC PATCH 3/3] tools/rbtree: fix null pointer dereference in erase
  2019-12-24 12:12 [RFC PATCH 1/3] selftests: add rbtree selftests Heiher
  2019-12-24 12:12 ` [RFC PATCH 2/3] lib/rbtree: fix null pointer dereference in erase Heiher
@ 2019-12-24 12:12 ` Heiher
  2019-12-24 17:00 ` [RFC PATCH 1/3] selftests: add rbtree selftests Hev
  2 siblings, 0 replies; 4+ messages in thread
From: Heiher @ 2019-12-24 12:12 UTC (permalink / raw)
  To: linux-kernel; +Cc: Heiher, Andrew Morton, Michel Lespinasse, Peter Zijlstra

a null pointer dereference in erasing the root node of below tree.

Tree structure:
                   (1)[2]
                  /   \
               (2)[1]  (3)[4]
                      /
                   (4)[3]

(n): Insert order
[n]: Key value or key order

Signed-off-by: hev <r@hev.cc>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michel Lespinasse <walken@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
---
 tools/lib/rbtree.c | 94 +++++++++++++++++++++++-----------------------
 1 file changed, 48 insertions(+), 46 deletions(-)

diff --git a/tools/lib/rbtree.c b/tools/lib/rbtree.c
index 2548ff8c4d9c..8eb88439af57 100644
--- a/tools/lib/rbtree.c
+++ b/tools/lib/rbtree.c
@@ -351,56 +351,58 @@ ____rb_erase_color(struct rb_node *parent, struct rb_root *root,
 			break;
 		} else {
 			sibling = parent->rb_left;
-			if (rb_is_red(sibling)) {
-				/* Case 1 - right rotate at parent */
-				tmp1 = sibling->rb_right;
-				WRITE_ONCE(parent->rb_left, tmp1);
-				WRITE_ONCE(sibling->rb_right, parent);
-				rb_set_parent_color(tmp1, parent, RB_BLACK);
-				__rb_rotate_set_parents(parent, sibling, root,
-							RB_RED);
-				augment_rotate(parent, sibling);
-				sibling = tmp1;
-			}
-			tmp1 = sibling->rb_left;
-			if (!tmp1 || rb_is_black(tmp1)) {
-				tmp2 = sibling->rb_right;
-				if (!tmp2 || rb_is_black(tmp2)) {
-					/* Case 2 - sibling color flip */
-					rb_set_parent_color(sibling, parent,
-							    RB_RED);
-					if (rb_is_red(parent))
-						rb_set_black(parent);
-					else {
-						node = parent;
-						parent = rb_parent(node);
-						if (parent)
-							continue;
+			if (sibling) {
+				if (rb_is_red(sibling)) {
+					/* Case 1 - right rotate at parent */
+					tmp1 = sibling->rb_right;
+					WRITE_ONCE(parent->rb_left, tmp1);
+					WRITE_ONCE(sibling->rb_right, parent);
+					rb_set_parent_color(tmp1, parent, RB_BLACK);
+					__rb_rotate_set_parents(parent, sibling, root,
+								RB_RED);
+					augment_rotate(parent, sibling);
+					sibling = tmp1;
+				}
+				tmp1 = sibling->rb_left;
+				if (!tmp1 || rb_is_black(tmp1)) {
+					tmp2 = sibling->rb_right;
+					if (!tmp2 || rb_is_black(tmp2)) {
+						/* Case 2 - sibling color flip */
+						rb_set_parent_color(sibling, parent,
+									RB_RED);
+						if (rb_is_red(parent))
+							rb_set_black(parent);
+						else {
+							node = parent;
+							parent = rb_parent(node);
+							if (parent)
+								continue;
+						}
+						break;
 					}
-					break;
+					/* Case 3 - left rotate at sibling */
+					tmp1 = tmp2->rb_left;
+					WRITE_ONCE(sibling->rb_right, tmp1);
+					WRITE_ONCE(tmp2->rb_left, sibling);
+					WRITE_ONCE(parent->rb_left, tmp2);
+					if (tmp1)
+						rb_set_parent_color(tmp1, sibling,
+									RB_BLACK);
+					augment_rotate(sibling, tmp2);
+					tmp1 = sibling;
+					sibling = tmp2;
 				}
-				/* Case 3 - left rotate at sibling */
-				tmp1 = tmp2->rb_left;
-				WRITE_ONCE(sibling->rb_right, tmp1);
-				WRITE_ONCE(tmp2->rb_left, sibling);
+				/* Case 4 - right rotate at parent + color flips */
+				tmp2 = sibling->rb_right;
 				WRITE_ONCE(parent->rb_left, tmp2);
-				if (tmp1)
-					rb_set_parent_color(tmp1, sibling,
-							    RB_BLACK);
-				augment_rotate(sibling, tmp2);
-				tmp1 = sibling;
-				sibling = tmp2;
+				WRITE_ONCE(sibling->rb_right, parent);
+				rb_set_parent_color(tmp1, sibling, RB_BLACK);
+				if (tmp2)
+					rb_set_parent(tmp2, parent);
+				__rb_rotate_set_parents(parent, sibling, root,
+							RB_BLACK);
+				augment_rotate(parent, sibling);
 			}
-			/* Case 4 - right rotate at parent + color flips */
-			tmp2 = sibling->rb_right;
-			WRITE_ONCE(parent->rb_left, tmp2);
-			WRITE_ONCE(sibling->rb_right, parent);
-			rb_set_parent_color(tmp1, sibling, RB_BLACK);
-			if (tmp2)
-				rb_set_parent(tmp2, parent);
-			__rb_rotate_set_parents(parent, sibling, root,
-						RB_BLACK);
-			augment_rotate(parent, sibling);
 			break;
 		}
 	}
-- 
2.24.1


^ permalink raw reply related	[flat|nested] 4+ messages in thread

* Re: [RFC PATCH 1/3] selftests: add rbtree selftests
  2019-12-24 12:12 [RFC PATCH 1/3] selftests: add rbtree selftests Heiher
  2019-12-24 12:12 ` [RFC PATCH 2/3] lib/rbtree: fix null pointer dereference in erase Heiher
  2019-12-24 12:12 ` [RFC PATCH 3/3] tools/rbtree: " Heiher
@ 2019-12-24 17:00 ` Hev
  2 siblings, 0 replies; 4+ messages in thread
From: Hev @ 2019-12-24 17:00 UTC (permalink / raw)
  To: linux-kernel; +Cc: Andrew Morton, Michel Lespinasse, Peter Zijlstra

Hi,

On Tue, Dec 24, 2019 at 8:12 PM Heiher <r@hev.cc> wrote:
>
> This adds the selftest for rbtree. It will reproduce the crash at earsing.
>
> Signed-off-by: hev <r@hev.cc>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Michel Lespinasse <walken@google.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> ---
>  tools/testing/selftests/Makefile              |  1 +
>  tools/testing/selftests/lib/rbtree/.gitignore |  1 +
>  tools/testing/selftests/lib/rbtree/Makefile   | 29 ++++++++
>  .../selftests/lib/rbtree/rbtree_test.c        | 70 +++++++++++++++++++
>  4 files changed, 101 insertions(+)
>  create mode 100644 tools/testing/selftests/lib/rbtree/.gitignore
>  create mode 100644 tools/testing/selftests/lib/rbtree/Makefile
>  create mode 100644 tools/testing/selftests/lib/rbtree/rbtree_test.c
>
> diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
> index b001c602414b..0e84ca3f207f 100644
> --- a/tools/testing/selftests/Makefile
> +++ b/tools/testing/selftests/Makefile
> @@ -25,6 +25,7 @@ TARGETS += kcmp
>  TARGETS += kexec
>  TARGETS += kvm
>  TARGETS += lib
> +TARGETS += lib/rbtree
>  TARGETS += livepatch
>  TARGETS += membarrier
>  TARGETS += memfd
> diff --git a/tools/testing/selftests/lib/rbtree/.gitignore b/tools/testing/selftests/lib/rbtree/.gitignore
> new file mode 100644
> index 000000000000..4c9f82761fad
> --- /dev/null
> +++ b/tools/testing/selftests/lib/rbtree/.gitignore
> @@ -0,0 +1 @@
> +rbtree_test
> diff --git a/tools/testing/selftests/lib/rbtree/Makefile b/tools/testing/selftests/lib/rbtree/Makefile
> new file mode 100644
> index 000000000000..68fa9dad24a1
> --- /dev/null
> +++ b/tools/testing/selftests/lib/rbtree/Makefile
> @@ -0,0 +1,29 @@
> +# SPDX-License-Identifier: GPL-2.0
> +
> +CFLAGS += -I../../../../include/
> +
> +include ../../lib.mk
> +
> +# lib.mk TEST_CUSTOM_PROGS var is for custom tests that need special
> +# build rules. lib.mk will run and install them.
> +
> +TEST_CUSTOM_PROGS := $(OUTPUT)/rbtree_test
> +all: $(TEST_CUSTOM_PROGS)
> +
> +OBJS = rbtree_test.o
> +
> +LIBS = ../../../../lib/rbtree.o
> +
> +OBJS := $(patsubst %,$(OUTPUT)/%,$(OBJS))
> +LIBS := $(patsubst %,$(OUTPUT)/%,$(LIBS))
> +
> +$(TEST_CUSTOM_PROGS): $(LIBS) $(OBJS)
> +       $(CC) -o $(TEST_CUSTOM_PROGS) $(OBJS) $(LIBS) $(CFLAGS) $(LDFLAGS)
> +
> +$(OBJS): $(OUTPUT)/%.o: %.c
> +       $(CC) -c $^ -o $@ $(CFLAGS)
> +
> +$(LIBS): $(OUTPUT)/%.o: %.c
> +       $(CC) -c $^ -o $@ $(CFLAGS)
> +
> +EXTRA_CLEAN := $(TEST_CUSTOM_PROGS) $(OBJS) $(LIBS)
> diff --git a/tools/testing/selftests/lib/rbtree/rbtree_test.c b/tools/testing/selftests/lib/rbtree/rbtree_test.c
> new file mode 100644
> index 000000000000..11420541071a
> --- /dev/null
> +++ b/tools/testing/selftests/lib/rbtree/rbtree_test.c
> @@ -0,0 +1,70 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <stdlib.h>
> +#include <linux/rbtree.h>
> +#include "../../kselftest_harness.h"
> +
> +struct node {
> +       struct rb_node node;
> +       int key;
> +};
> +
> +static int _insert(struct rb_root *tree, int key)
> +{
> +       struct rb_node **new = &tree->rb_node, *parent = NULL;
> +       struct node *node;
> +
> +       while (*new) {
> +               struct node *this = container_of(*new, struct node, node);
> +
> +               if (key < this->key)
> +                       new = &((*new)->rb_left);
> +               else if (key > this->key)
> +                       new = &((*new)->rb_right);
> +               else
> +                       return 0;
> +       }
> +
> +       node = malloc(sizeof(struct node));
> +       if (!node)
> +               return 0;
> +
> +       node->key = key;
> +       rb_link_node(&node->node, parent, new);
> +       rb_insert_color(&node->node, tree);
> +
> +       return 1;
> +}
> +
> +static void _remove(struct rb_root *tree, int key)
> +{
> +       struct rb_node **node = &tree->rb_node;
> +
> +       while (*node) {
> +               struct node *this = container_of(*node, struct node, node);
> +
> +               if (key < this->key) {
> +                       node = &((*node)->rb_left);
> +               } else if (key > this->key) {
> +                       node = &((*node)->rb_right);
> +               } else {
> +                       rb_erase(&this->node, tree);
> +                       free(this);
> +                       return;
> +               }
> +       }
> +}
> +
> +TEST(rbtree)
> +{
> +       struct rb_root tree = { 0 };
> +
> +       _insert(&tree, 2);
> +       _insert(&tree, 1);
> +       _insert(&tree, 4);
> +       _insert(&tree, 3);
> +
> +       _remove(&tree, 2);
> +}
> +
> +TEST_HARNESS_MAIN
> --
> 2.24.1
>

Sorry, recall these patches.
It was my mistake. I forget to update the parent pointer at inserting. :(

-- 
Best regards!
Hev
https://hev.cc

^ permalink raw reply	[flat|nested] 4+ messages in thread

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2019-12-24 12:12 [RFC PATCH 1/3] selftests: add rbtree selftests Heiher
2019-12-24 12:12 ` [RFC PATCH 2/3] lib/rbtree: fix null pointer dereference in erase Heiher
2019-12-24 12:12 ` [RFC PATCH 3/3] tools/rbtree: " Heiher
2019-12-24 17:00 ` [RFC PATCH 1/3] selftests: add rbtree selftests Hev

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