diff -Naur linux-2.6.35.utrace.vm2/include/linux/mm.h linux-2.6.35.utrace.vm3/include/linux/mm.h
--- linux-2.6.35.utrace.vm2/include/linux/mm.h	2010-08-11 22:06:36.000000000 +0200
+++ linux-2.6.35.utrace.vm3/include/linux/mm.h	2010-08-11 22:10:24.000000000 +0200
@@ -838,7 +838,10 @@
 #endif
 
 extern int make_pages_present(unsigned long addr, unsigned long end);
-extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write);
+extern int access_process_vm(struct task_struct *tsk, unsigned long addr,
+		void *buf, int len, int write);
+extern int access_process_vm_user(struct task_struct *tsk, unsigned long addr,
+		char __user *ubuf, int len, int write, int string);
 
 int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
 			unsigned long start, int nr_pages, int write, int force,
diff -Naur linux-2.6.35.utrace.vm2/include/linux/ptrace.h linux-2.6.35.utrace.vm3/include/linux/ptrace.h
--- linux-2.6.35.utrace.vm2/include/linux/ptrace.h	2010-08-11 22:06:36.000000000 +0200
+++ linux-2.6.35.utrace.vm3/include/linux/ptrace.h	2010-08-11 22:10:24.000000000 +0200
@@ -47,6 +47,18 @@
 #define PTRACE_GETREGSET	0x4204
 #define PTRACE_SETREGSET	0x4205
 
+#define PTRACE_MULTI            0x4300
+#define PTRACE_PEEKCHARDATA     0x4301
+#define PTRACE_POKECHARDATA     0x4302
+#define PTRACE_PEEKSTRINGDATA   0x4303
+
+struct ptrace_multi {
+	long request;
+	long addr;
+	void *localaddr;
+	long length;
+};
+
 /* options set using PTRACE_SETOPTIONS */
 #define PTRACE_O_TRACESYSGOOD	0x00000001
 #define PTRACE_O_TRACEFORK	0x00000002
@@ -109,11 +121,12 @@
 #include <linux/compiler.h>		/* For unlikely.  */
 #include <linux/sched.h>		/* For struct task_struct.  */
 
+#include <linux/mm.h>   /* For access_vm*.  */
+#include <linux/uaccess.h>    /* For *_ACCESS */
+
 extern void ptrace_notify_stop(struct task_struct *tracee);
 extern long arch_ptrace(struct task_struct *child, long request, long addr, long data);
 extern int ptrace_traceme(void);
-extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
-extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
 extern int ptrace_attach(struct task_struct *tsk);
 extern bool __ptrace_detach(struct task_struct *tracer, struct task_struct *tracee);
 extern int ptrace_detach(struct task_struct *, unsigned int);
@@ -132,6 +145,30 @@
 /* Returns true on success, false on denial. */
 extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
 
+static inline int ptrace_readdata(struct task_struct *tsk, unsigned long src,
+		char __user *dst, int len)
+{
+	if (!access_ok(VERIFY_WRITE, dst, len))
+		return -EIO;
+	return access_process_vm_user(tsk, src, dst, len, 0, 0);
+}
+
+static inline int ptrace_readstringdata(struct task_struct *tsk, unsigned long src,
+		char __user *dst, int len)
+{
+	if (!access_ok(VERIFY_WRITE, dst, len))
+		return -EIO;
+	return access_process_vm_user(tsk, src, dst, len, 0, 1);
+}
+
+static inline int ptrace_writedata(struct task_struct *tsk, char __user *src,
+		unsigned long dst, int len)
+{
+	if (!access_ok(VERIFY_READ, dst, len))
+		return -EIO;
+	return access_process_vm_user(tsk, dst, src, len, 1, 0);
+}
+
 static inline int ptrace_reparented(struct task_struct *child)
 {
 	return child->real_parent != child->parent;
diff -Naur linux-2.6.35.utrace.vm2/kernel/ptrace.c linux-2.6.35.utrace.vm3/kernel/ptrace.c
--- linux-2.6.35.utrace.vm2/kernel/ptrace.c	2010-08-11 22:06:36.000000000 +0200
+++ linux-2.6.35.utrace.vm3/kernel/ptrace.c	2010-08-11 22:11:39.000000000 +0200
@@ -2,6 +2,7 @@
  * linux/kernel/ptrace.c
  *
  * (C) Copyright 1999 Linus Torvalds
+ * PTRACE_MULTI support 2009 Renzo Davoli
  *
  * Common interfaces for "ptrace()" which we do not want
  * to continually duplicate across every architecture.
@@ -121,56 +122,6 @@
 	return false;
 }
 
-int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
-{
-	int copied = 0;
-
-	while (len > 0) {
-		char buf[128];
-		int this_len, retval;
-
-		this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
-		retval = access_process_vm(tsk, src, buf, this_len, 0);
-		if (!retval) {
-			if (copied)
-				break;
-			return -EIO;
-		}
-		if (copy_to_user(dst, buf, retval))
-			return -EFAULT;
-		copied += retval;
-		src += retval;
-		dst += retval;
-		len -= retval;
-	}
-	return copied;
-}
-
-int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
-{
-	int copied = 0;
-
-	while (len > 0) {
-		char buf[128];
-		int this_len, retval;
-
-		this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
-		if (copy_from_user(buf, src, this_len))
-			return -EFAULT;
-		retval = access_process_vm(tsk, dst, buf, this_len, 1);
-		if (!retval) {
-			if (copied)
-				break;
-			return -EIO;
-		}
-		copied += retval;
-		src += retval;
-		dst += retval;
-		len -= retval;
-	}
-	return copied;
-}
-
 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
 
 static const struct user_regset *
@@ -231,6 +182,58 @@
 #define arch_ptrace_attach(child)	do { } while (0)
 #endif
 
+static int multi_ptrace(struct task_struct *child, long request, long addr,
+		long size)
+{
+	int i, ret;
+	long j;
+	ret = 0;
+	if (!access_ok(VERIFY_READ, addr, size*sizeof(struct ptrace_multi))) {
+		ret = -EIO;
+		goto out_multi_ptrace;
+	}
+	for (i = 0; i < size && ret == 0; i++,
+			addr += sizeof(struct ptrace_multi)) {
+		unsigned long len;
+		struct ptrace_multi __user pm ;
+		if (unlikely(__copy_from_user(&pm, (struct ptrace_multi __user *)addr,
+					sizeof(struct ptrace_multi)) != 0))
+			continue;
+		len = pm.length;
+		switch (pm.request) {
+		case PTRACE_PEEKTEXT:
+		case PTRACE_PEEKDATA:
+		case PTRACE_PEEKUSR:
+		case PTRACE_POKETEXT:
+		case PTRACE_POKEDATA:
+		case PTRACE_POKEUSR:
+			if (len <= 0)
+				len = 1;
+			for (j = 0; j < len && ret == 0; j++)
+				ret = arch_ptrace(child, pm.request,
+					(long) (pm.addr) + j * sizeof(long),
+					(long) (pm.localaddr) + j * sizeof(long));
+			break;
+		case PTRACE_PEEKCHARDATA:
+			ret = ptrace_readdata(child, pm.addr, pm.localaddr, len);
+			break;
+		case PTRACE_POKECHARDATA:
+			ret = ptrace_writedata(child, pm.localaddr, pm.addr, len);
+			break;
+		case PTRACE_PEEKSTRINGDATA:
+			ret = ptrace_readstringdata(child, pm.addr, pm.localaddr, len);
+			break;
+		default:
+			ret = arch_ptrace(child, pm.request, (long) (pm.addr),
+					(long) (pm.localaddr));
+			break;
+		}
+	}
+out_multi_ptrace:
+	return ret;
+}
+
+
 SYSCALL_DEFINE4(ptrace, long, request, long, pid, long, addr, long, data)
 {
 	struct task_struct *child;
@@ -264,11 +267,14 @@
 	if (ret < 0)
 		goto out_put_task_struct;
 
-	ret = arch_ptrace(child, request, addr, data);
+	if (request == PTRACE_MULTI)
+		ret = multi_ptrace(child, request, addr, data);
+	else
+		ret = arch_ptrace(child, request, addr, data);
 
- out_put_task_struct:
+out_put_task_struct:
 	put_task_struct(child);
- out:
+out:
 	return ret;
 }
 
@@ -294,8 +300,71 @@
 #if defined CONFIG_COMPAT
 #include <linux/compat.h>
 
+struct compat_ptrace_multi {
+	compat_long_t request;
+	compat_ulong_t addr;
+	compat_ulong_t localaddr;
+	compat_ulong_t length;
+};
+
+static int compat_multi_ptrace(struct task_struct *child,
+		compat_long_t request, compat_ulong_t addr, compat_ulong_t size)
+{
+	int i, ret;
+	compat_long_t j;
+	ret = 0;
+	if (!access_ok(VERIFY_READ, addr,
+				size*sizeof(struct compat_ptrace_multi))) {
+		ret = -EIO;
+		goto out_multi_ptrace;
+	}
+	for (i = 0; i < size && ret == 0;
+			i++, addr += sizeof(struct compat_ptrace_multi)) {
+		compat_ulong_t len;
+		struct compat_ptrace_multi __user pm ;
+		if (unlikely(__copy_from_user(&pm,
+						(struct compat_ptrace_multi __user *)
+						(u_long)addr, sizeof(struct compat_ptrace_multi)) != 0))
+			continue;
+		len = pm.length;
+		switch (pm.request) {
+			case PTRACE_PEEKTEXT:
+			case PTRACE_PEEKDATA:
+			case PTRACE_PEEKUSR:
+			case PTRACE_POKETEXT:
+			case PTRACE_POKEDATA:
+			case PTRACE_POKEUSR:
+				if (len <= 0)
+					len = 1;
+				for (j = 0; j < len && ret == 0; j++)
+					ret = compat_arch_ptrace(child, pm.request,
+							(compat_long_t) (pm.addr) + j * sizeof(compat_long_t),
+							(compat_ulong_t) (pm.localaddr) + j * sizeof(compat_long_t));
+				break;
+			case PTRACE_PEEKCHARDATA:
+				ret = ptrace_readdata(child, pm.addr,
+						(char __user *)(long)pm.localaddr, len);
+				break;
+			case PTRACE_POKECHARDATA:
+				ret = ptrace_writedata(child,
+						(char __user *)(long)pm.localaddr, pm.addr, len);
+				break;
+			case PTRACE_PEEKSTRINGDATA:
+				ret = ptrace_readstringdata(child, pm.addr,
+						(char __user *)(long)pm.localaddr, len);
+				break;
+			default:
+				ret = compat_arch_ptrace(child, pm.request,
+						(compat_ulong_t) (pm.addr), (compat_ulong_t) (pm.localaddr));
+				break;
+		}
+	}
+out_multi_ptrace:
+	return ret;
+}
+
 asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid,
-				  compat_long_t addr, compat_long_t data)
+		compat_long_t addr, compat_long_t data)
 {
 	struct task_struct *child;
 	long ret;
@@ -323,8 +392,12 @@
 	}
 
 	ret = ptrace_check_attach(child, request == PTRACE_KILL);
-	if (!ret)
-		ret = compat_arch_ptrace(child, request, addr, data);
+	if (!ret) {
+		if (request == PTRACE_MULTI)
+			ret = compat_multi_ptrace(child, request, addr, data);
+		else
+			ret = compat_arch_ptrace(child, request, addr, data);
+	}
 
  out_put_task_struct:
 	put_task_struct(child);
@@ -824,14 +897,14 @@
 		ret = ptrace_getsiginfo(child, &siginfo);
 		if (!ret)
 			ret = copy_siginfo_to_user32(
-				(struct compat_siginfo __user *) datap,
-				&siginfo);
+					(struct compat_siginfo __user *) datap,
+					&siginfo);
 		break;
 
 	case PTRACE_SETSIGINFO:
 		memset(&siginfo, 0, sizeof siginfo);
 		if (copy_siginfo_from_user32(
-			    &siginfo, (struct compat_siginfo __user *) datap))
+					&siginfo, (struct compat_siginfo __user *) datap))
 			ret = -EFAULT;
 		else
 			ret = ptrace_setsiginfo(child, &siginfo);
diff -Naur linux-2.6.35.utrace.vm2/mm/memory.c linux-2.6.35.utrace.vm3/mm/memory.c
--- linux-2.6.35.utrace.vm2/mm/memory.c	2010-08-11 22:06:36.000000000 +0200
+++ linux-2.6.35.utrace.vm3/mm/memory.c	2010-08-11 22:10:24.000000000 +0200
@@ -3460,6 +3460,75 @@
 }
 
 /*
+ * Access another process' address space to/from user space
+ * Do not walk the page table directly, use get_user_pages
+ */
+int access_process_vm_user(struct task_struct *tsk, unsigned long addr,
+		char __user *ubuf, int len, int write, int string)
+{
+	struct mm_struct *mm;
+	struct vm_area_struct *vma;
+	struct page *page;
+	char *buf;
+	unsigned long old_addr = addr;
+
+	mm = get_task_mm(tsk);
+	if (!mm)
+		return 0;
+
+	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!buf)
+		return 0;
+
+	down_read(&mm->mmap_sem);
+	/* ignore errors, just check how much was sucessfully transfered */
+	while (len) {
+		int bytes, ret, offset;
+		void *maddr;
+
+		ret = get_user_pages(tsk, mm, addr, 1,
+				write, 1, &page, &vma);
+		if (ret <= 0)
+			break;
+
+		bytes = len;
+		offset = addr & (PAGE_SIZE-1);
+		if (bytes > PAGE_SIZE-offset)
+			bytes = PAGE_SIZE-offset;
+
+		maddr = kmap(page);
+		if (write) {
+			__copy_from_user(buf, ubuf, bytes);
+			copy_to_user_page(vma, page, addr,
+					maddr + offset, buf, bytes);
+			if (!PageCompound(page))
+				set_page_dirty_lock(page);
+		} else {
+			copy_from_user_page(vma, page, addr,
+					buf, maddr + offset, bytes);
+			if (string) {
+				for (offset = 0; offset < bytes; offset++)
+					if (buf[offset] == 0)
+						break;
+				if (offset < bytes)
+					bytes = len = offset + 1;
+			}
+			ret = __copy_to_user(ubuf, buf, bytes);
+		}
+		kunmap(page);
+		page_cache_release(page);
+		len -= bytes;
+		ubuf += bytes;
+		addr += bytes;
+	}
+	up_read(&mm->mmap_sem);
+	mmput(mm);
+
+	kfree(buf);
+	return addr - old_addr;
+}
+
+/*
  * Print the name of a VMA.
  */
 void print_vma_addr(char *prefix, unsigned long ip)
diff -Naur linux-2.6.35.utrace.vm2/mm/nommu.c linux-2.6.35.utrace.vm3/mm/nommu.c
--- linux-2.6.35.utrace.vm2/mm/nommu.c	2010-08-11 22:06:36.000000000 +0200
+++ linux-2.6.35.utrace.vm3/mm/nommu.c	2010-08-11 22:10:24.000000000 +0200
@@ -2003,3 +2003,15 @@
 	up_write(&nommu_region_sem);
 	return 0;
 }
+
+/*
+ * Access another process' address space to/from user space
+ * Do not walk the page table directly, use get_user_pages
+ * Unimplemented yet. 
+ */
+int access_process_vm_user(struct task_struct *tsk, unsigned long addr,
+		    char __user *ubuf, int len, int write, int string)
+{
+	return -EIO;
+}
+