* Re: [PATCH 34/45] C++: Fix up use of LIST_POISON*
@ 2018-04-01 21:28 Alexey Dobriyan
0 siblings, 0 replies; 2+ messages in thread
From: Alexey Dobriyan @ 2018-04-01 21:28 UTC (permalink / raw)
To: dhowells; +Cc: linux-kernel
> - entry->next = LIST_POISON1;
> - entry->prev = LIST_POISON2;
> + entry->next = static_cast<struct list_head *>(LIST_POISON1);
> + entry->prev = static_cast<struct list_head *>(LIST_POISON2);
There is a better way ;-)
--- a/include/linux/poison.h
+++ b/include/linux/poison.h
@@ -2,6 +2,22 @@
#ifndef _LINUX_POISON_H
#define _LINUX_POISON_H
+class POISON {
+ unsigned long p;
+
+public:
+ explicit POISON(unsigned long val)
+ : p{val}
+ {
+ }
+
+ template<typename T>
+ operator T*() const
+ {
+ return p;
+ }
+};
+
/********** include/linux/list.h **********/
/*
@@ -20,15 +36,15 @@
* under normal circumstances, used to verify that nobody uses
* non-initialized list entries.
*/
-#define LIST_POISON1 ((void *) 0x100 + POISON_POINTER_DELTA)
-#define LIST_POISON2 ((void *) 0x200 + POISON_POINTER_DELTA)
+#define LIST_POISON1 POISON{0x100UL + POISON_POINTER_DELTA}
+#define LIST_POISON2 POISON{0x200UL + POISON_POINTER_DELTA}
/********** include/linux/timer.h **********/
/*
* Magic number "tsta" to indicate a static timer initializer
* for the object debugging code.
*/
-#define TIMER_ENTRY_STATIC ((void *) 0x300 + POISON_POINTER_DELTA)
+#define TIMER_ENTRY_STATIC POISON{0x300UL + POISON_POINTER_DELTA}
/********** mm/debug-pagealloc.c **********/
#ifdef CONFIG_PAGE_POISONING_ZERO
@@ -39,7 +55,7 @@
/********** mm/page_alloc.c ************/
-#define TAIL_MAPPING ((void *) 0x400 + POISON_POINTER_DELTA)
+#define TAIL_MAPPING POISON{0x400UL + POISON_POINTER_DELTA}
/********** mm/slab.c **********/
/*
@@ -81,7 +97,7 @@
/********** kernel/mutexes **********/
#define MUTEX_DEBUG_INIT 0x11
#define MUTEX_DEBUG_FREE 0x22
-#define MUTEX_POISON_WW_CTX ((void *) 0x500 + POISON_POINTER_DELTA)
+#define MUTEX_POISON_WW_CTX POISON{0x500UL + POISON_POINTER_DELTA}
/********** lib/flex_array.c **********/
#define FLEX_ARRAY_FREE 0x6c /* for use-after-free poisoning */
^ permalink raw reply [flat|nested] 2+ messages in thread
* [PATCH 34/45] C++: Fix up use of LIST_POISON*
2018-04-01 20:40 [PATCH 00/45] C++: Convert the kernel to C++ David Howells
@ 2018-04-01 20:43 ` David Howells
0 siblings, 0 replies; 2+ messages in thread
From: David Howells @ 2018-04-01 20:43 UTC (permalink / raw)
To: linux-kernel
Implicitly casting void* to a non-void pointer is frowned upon in C++,
though -fpermissive causes it to be accepted. Fix up LIST_POISON1/2
somewhat to handle this a bit better.
Signed-off-by: David Howells <dhowells@redhat.com>
---
include/linux/list.h | 8 ++++----
include/linux/list_bl.h | 4 ++--
include/linux/list_nulls.h | 2 +-
include/linux/poison.h | 6 ++++--
include/linux/rculist.h | 4 ++--
include/linux/rculist_bl.h | 2 +-
6 files changed, 14 insertions(+), 12 deletions(-)
diff --git a/include/linux/list.h b/include/linux/list.h
index 4b129df4d46b..6aa933e4b109 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -123,8 +123,8 @@ static inline void __list_del_entry(struct list_head *entry)
static inline void list_del(struct list_head *entry)
{
__list_del_entry(entry);
- entry->next = LIST_POISON1;
- entry->prev = LIST_POISON2;
+ entry->next = static_cast<struct list_head *>(LIST_POISON1);
+ entry->prev = static_cast<struct list_head *>(LIST_POISON2);
}
/**
@@ -654,8 +654,8 @@ static inline void __hlist_del(struct hlist_node *n)
static inline void hlist_del(struct hlist_node *n)
{
__hlist_del(n);
- n->next = LIST_POISON1;
- n->pprev = LIST_POISON2;
+ n->next = HLIST_POISON1;
+ n->pprev = HLIST_POISON2;
}
static inline void hlist_del_init(struct hlist_node *n)
diff --git a/include/linux/list_bl.h b/include/linux/list_bl.h
index 3fc2cc57ba1b..474c87c2e72e 100644
--- a/include/linux/list_bl.h
+++ b/include/linux/list_bl.h
@@ -105,8 +105,8 @@ static inline void __hlist_bl_del(struct hlist_bl_node *n)
static inline void hlist_bl_del(struct hlist_bl_node *n)
{
__hlist_bl_del(n);
- n->next = LIST_POISON1;
- n->pprev = LIST_POISON2;
+ n->next = ((struct hlist_bl_node *) (0x100 + POISON_POINTER_DELTA));
+ n->pprev = ((struct hlist_bl_node **) (0x200 + POISON_POINTER_DELTA));
}
static inline void hlist_bl_del_init(struct hlist_bl_node *n)
diff --git a/include/linux/list_nulls.h b/include/linux/list_nulls.h
index 3ef96743db8d..6c471fd62c9c 100644
--- a/include/linux/list_nulls.h
+++ b/include/linux/list_nulls.h
@@ -91,7 +91,7 @@ static inline void __hlist_nulls_del(struct hlist_nulls_node *n)
static inline void hlist_nulls_del(struct hlist_nulls_node *n)
{
__hlist_nulls_del(n);
- n->pprev = LIST_POISON2;
+ n->pprev = (struct hlist_nulls_node **)LIST_POISON2;
}
/**
diff --git a/include/linux/poison.h b/include/linux/poison.h
index 15927ebc22f2..21544c2bf1a7 100644
--- a/include/linux/poison.h
+++ b/include/linux/poison.h
@@ -20,8 +20,10 @@
* under normal circumstances, used to verify that nobody uses
* non-initialized list entries.
*/
-#define LIST_POISON1 ((void *) 0x100 + POISON_POINTER_DELTA)
-#define LIST_POISON2 ((void *) 0x200 + POISON_POINTER_DELTA)
+#define LIST_POISON1 ((struct list_head *) (0x100 + POISON_POINTER_DELTA))
+#define LIST_POISON2 ((struct list_head *) (0x200 + POISON_POINTER_DELTA))
+#define HLIST_POISON1 ((struct hlist_node *) (0x100 + POISON_POINTER_DELTA))
+#define HLIST_POISON2 ((struct hlist_node **) (0x200 + POISON_POINTER_DELTA))
/********** include/linux/timer.h **********/
/*
diff --git a/include/linux/rculist.h b/include/linux/rculist.h
index 127f534fec94..d7b6a0a697c8 100644
--- a/include/linux/rculist.h
+++ b/include/linux/rculist.h
@@ -425,7 +425,7 @@ static inline void list_splice_tail_init_rcu(struct list_head *list,
static inline void hlist_del_rcu(struct hlist_node *n)
{
__hlist_del(n);
- n->pprev = LIST_POISON2;
+ n->pprev = HLIST_POISON2;
}
/**
@@ -445,7 +445,7 @@ static inline void hlist_replace_rcu(struct hlist_node *old,
rcu_assign_pointer(*(struct hlist_node __rcu **)new->pprev, new);
if (next)
new->next->pprev = &new->next;
- old->pprev = LIST_POISON2;
+ old->pprev = HLIST_POISON2;
}
/*
diff --git a/include/linux/rculist_bl.h b/include/linux/rculist_bl.h
index 66e73ec1aa99..e5a2c59deb6d 100644
--- a/include/linux/rculist_bl.h
+++ b/include/linux/rculist_bl.h
@@ -74,7 +74,7 @@ static inline void hlist_bl_del_init_rcu(struct hlist_bl_node *n)
static inline void hlist_bl_del_rcu(struct hlist_bl_node *n)
{
__hlist_bl_del(n);
- n->pprev = LIST_POISON2;
+ n->pprev = ((struct hlist_bl_node **) (0x200 + POISON_POINTER_DELTA));
}
/**
^ permalink raw reply related [flat|nested] 2+ messages in thread
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