[PATCH 25/25] Unionfs: use poison.h for safe poison pointers

Erez Zadok
2007-09-26T03:37:04Z

This also fixes a compile warning on 64-bit systems.

Signed-off-by: Josef 'Jeff' Sipek <jsipek@cs.sunysb.edu>
Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>
---
fs/unionfs/debug.c | 16 ++++++----------
fs/unionfs/union.h | 1 +
2 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/fs/unionfs/debug.c b/fs/unionfs/debug.c
index 09b52ce..b103eb9 100644
--- a/fs/unionfs/debug.c
+++ b/fs/unionfs/debug.c
@@ -25,14 +25,6 @@
} \
} while (0)

-#if BITS_PER_LONG == 32
-#define POISONED_PTR ((void*) 0x5a5a5a5a)
-#elif BITS_PER_LONG == 64
-#define POISONED_PTR ((void*) 0x5a5a5a5a5a5a5a5a)
-#else
-#error Unknown BITS_PER_LONG value
-#endif /* BITS_PER_LONG != known */
-
/*
* __unionfs_check_{inode,dentry,file} perform exhaustive sanity checking on
* the fan-out of various Unionfs objects. We check that no lower objects
@@ -50,6 +42,7 @@ void __unionfs_check_inode(const struct inode *inode,
struct inode *lower_inode;
struct super_block *sb;
int printed_caller = 0;
+ void *poison_ptr;

/* for inodes now */
BUG_ON(!inode);
@@ -88,12 +81,13 @@ void __unionfs_check_inode(const struct inode *inode,
}
lower_inode = unionfs_lower_inode_idx(inode, bindex);
if (lower_inode) {
+ memset(&poison_ptr, POISON_INUSE, sizeof(void *));
if (unlikely(bindex < istart || bindex > iend)) {
PRINT_CALLER(fname, fxn, line);
printk(" Ci5: inode/linode=%p:%p bindex=%d "
"istart/end=%d:%d\n", inode,
lower_inode, bindex, istart, iend);
- } else if (unlikely(lower_inode == POISONED_PTR)) {
+ } else if (unlikely(lower_inode == poison_ptr)) {
/* freed inode! */
PRINT_CALLER(fname, fxn, line);
printk(" Ci6: inode/linode=%p:%p bindex=%d "
@@ -131,6 +125,7 @@ void __unionfs_check_dentry(const struct dentry *dentry,
struct super_block *sb;
struct vfsmount *lower_mnt;
int printed_caller = 0;
+ void *poison_ptr;

BUG_ON(!dentry);
sb = dentry->d_sb;
@@ -257,12 +252,13 @@ void __unionfs_check_dentry(const struct dentry *dentry,
for (bindex = sbstart(sb); bindex < sbmax(sb); bindex++) {
lower_inode = unionfs_lower_inode_idx(inode, bindex);
if (lower_inode) {
+ memset(&poison_ptr, POISON_INUSE, sizeof(void *));
if (unlikely(bindex < istart || bindex > iend)) {
PRINT_CALLER(fname, fxn, line);
printk(" CI5: dentry/linode=%p:%p bindex=%d "
"istart/end=%d:%d\n", dentry,
lower_inode, bindex, istart, iend);
- } else if (unlikely(lower_inode == POISONED_PTR)) {
+ } else if (unlikely(lower_inode == poison_ptr)) {
/* freed inode! */
PRINT_CALLER(fname, fxn, line);
printk(" CI6: dentry/linode=%p:%p bindex=%d "
diff --git a/fs/unionfs/union.h b/fs/unionfs/union.h
index 8df44a9..510267f 100644
--- a/fs/unionfs/union.h
+++ b/fs/unionfs/union.h
@@ -43,6 +43,7 @@
#include <linux/fs_stack.h>
#include <linux/magic.h>
#include <linux/log2.h>
+#include <linux/poison.h>

#include <asm/mman.h>
#include <asm/system.h>
--
1.5.2.2