diff -Naur linux-2.6.21/arch/i386/kernel/ptrace.c linux-2.6.21-ptmulti-ptvm/arch/i386/kernel/ptrace.c
--- linux-2.6.21/arch/i386/kernel/ptrace.c	2007-04-26 05:08:32.000000000 +0200
+++ linux-2.6.21-ptmulti-ptvm/arch/i386/kernel/ptrace.c	2008-05-18 20:49:37.000000000 +0200
@@ -473,15 +473,26 @@
 		  }
 		  break;
 
+	case PTRACE_SYSVM:
+		if (addr == PTRACE_VM_TEST) {
+			ret = PTRACE_VM_MASK;
+			break;
+		}
+
 	case PTRACE_SYSEMU: /* continue and stop at next syscall, which will not be executed */
 	case PTRACE_SYSCALL:	/* continue and stop at next (return from) syscall */
 	case PTRACE_CONT:	/* restart after signal. */
 		ret = -EIO;
 		if (!valid_signal(data))
 			break;
+		child->ptrace &= ~PT_VM_MASK;
 		if (request == PTRACE_SYSEMU) {
 			set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
 			clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+		} else if (request == PTRACE_SYSVM) {
+			set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+			clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
+			child->ptrace |= (addr & PTRACE_VM_MASK) << 28;
 		} else if (request == PTRACE_SYSCALL) {
 			set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 			clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
@@ -686,6 +697,9 @@
 	if (!(current->ptrace & PT_PTRACED))
 		goto out;
 
+	if (entryexit && (current->ptrace & PT_VM_SKIPEXIT))
+		return 0;
+
 	/* If a process stops on the 1st tracepoint with SYSCALL_TRACE
 	 * and then is resumed with SYSEMU_SINGLESTEP, it will come in
 	 * here. We have to check this and return */
@@ -713,7 +727,7 @@
 		send_sig(current->exit_code, current, 1);
 		current->exit_code = 0;
 	}
-	ret = is_sysemu;
+	ret = (is_sysemu || (!entryexit && (current->ptrace & PT_VM_SKIPCALL)));
 out:
 	if (unlikely(current->audit_context) && !entryexit)
 		audit_syscall_entry(AUDIT_ARCH_I386, regs->orig_eax,
diff -Naur linux-2.6.21/arch/powerpc/kernel/entry_32.S linux-2.6.21-ptmulti-ptvm/arch/powerpc/kernel/entry_32.S
--- linux-2.6.21/arch/powerpc/kernel/entry_32.S	2007-04-26 05:08:32.000000000 +0200
+++ linux-2.6.21-ptmulti-ptvm/arch/powerpc/kernel/entry_32.S	2008-05-18 20:50:09.000000000 +0200
@@ -277,6 +277,7 @@
 	stw	r0,_TRAP(r1)
 	addi	r3,r1,STACK_FRAME_OVERHEAD
 	bl	do_syscall_trace_enter
+	mr      r10,r3
 	lwz	r0,GPR0(r1)	/* Restore original registers */
 	lwz	r3,GPR3(r1)
 	lwz	r4,GPR4(r1)
@@ -285,6 +286,8 @@
 	lwz	r7,GPR7(r1)
 	lwz	r8,GPR8(r1)
 	REST_NVGPRS(r1)
+	cmpwi   r10,0
+	bne-    ret_from_syscall
 	b	syscall_dotrace_cont
 
 syscall_exit_work:
diff -Naur linux-2.6.21/arch/powerpc/kernel/entry_64.S linux-2.6.21-ptmulti-ptvm/arch/powerpc/kernel/entry_64.S
--- linux-2.6.21/arch/powerpc/kernel/entry_64.S	2007-04-26 05:08:32.000000000 +0200
+++ linux-2.6.21-ptmulti-ptvm/arch/powerpc/kernel/entry_64.S	2008-05-18 20:50:38.000000000 +0200
@@ -203,6 +203,7 @@
 	bl	.save_nvgprs
 	addi	r3,r1,STACK_FRAME_OVERHEAD
 	bl	.do_syscall_trace_enter
+	mr      r11,r3
 	ld	r0,GPR0(r1)	/* Restore original registers */
 	ld	r3,GPR3(r1)
 	ld	r4,GPR4(r1)
@@ -213,6 +214,8 @@
 	addi	r9,r1,STACK_FRAME_OVERHEAD
 	clrrdi	r10,r1,THREAD_SHIFT
 	ld	r10,TI_FLAGS(r10)
+	cmpwi   r11,0
+	bne-    syscall_exit
 	b	syscall_dotrace_cont
 
 syscall_enosys:
diff -Naur linux-2.6.21/arch/powerpc/kernel/ptrace.c linux-2.6.21-ptmulti-ptvm/arch/powerpc/kernel/ptrace.c
--- linux-2.6.21/arch/powerpc/kernel/ptrace.c	2007-04-26 05:08:32.000000000 +0200
+++ linux-2.6.21-ptmulti-ptvm/arch/powerpc/kernel/ptrace.c	2008-05-18 21:36:02.000000000 +0200
@@ -337,15 +337,28 @@
 		break;
 	}
 
+	case PTRACE_SYSVM: 
+		if (addr == PTRACE_VM_TEST) {
+			ret = PTRACE_VM_MASK;
+			break;
+		}
+
 	case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 	case PTRACE_CONT: { /* restart after signal. */
 		ret = -EIO;
 		if (!valid_signal(data))
 			break;
-		if (request == PTRACE_SYSCALL)
-			set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-		else
+		child->ptrace &= ~PT_VM_MASK;
+		if (request == PTRACE_CONT)
 			clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+		else {
+			set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+			if (request == PTRACE_SYSVM) {
+				/* set PT_VM_SKIPCALL and PT_VM_SKIPEXIT by
+				 * one operation */
+				child->ptrace |= (addr & PTRACE_VM_MASK) << 28;
+			}
+		}
 		child->exit_code = data;
 		/* make sure the single step bit is not set. */
 		clear_single_step(child);
@@ -524,7 +537,7 @@
 	}
 }
 
-void do_syscall_trace_enter(struct pt_regs *regs)
+int do_syscall_trace_enter(struct pt_regs *regs)
 {
 	secure_computing(regs->gpr[0]);
 
@@ -548,6 +561,7 @@
 					    regs->gpr[5] & 0xffffffff,
 					    regs->gpr[6] & 0xffffffff);
 	}
+	return (current->ptrace & PT_VM_SKIPCALL);
 }
 
 void do_syscall_trace_leave(struct pt_regs *regs)
@@ -558,6 +572,7 @@
 
 	if ((test_thread_flag(TIF_SYSCALL_TRACE)
 	     || test_thread_flag(TIF_SINGLESTEP))
-	    && (current->ptrace & PT_PTRACED))
+	    && (current->ptrace & PT_PTRACED) && 
+	    ((current->ptrace & PT_VM_SKIPEXIT)==0))
 		do_syscall_trace();
 }
diff -Naur linux-2.6.21/arch/ppc/kernel/entry.S linux-2.6.21-ptmulti-ptvm/arch/ppc/kernel/entry.S
--- linux-2.6.21/arch/ppc/kernel/entry.S	2007-04-26 05:08:32.000000000 +0200
+++ linux-2.6.21-ptmulti-ptvm/arch/ppc/kernel/entry.S	2008-05-18 20:53:31.000000000 +0200
@@ -277,6 +277,7 @@
 	stw	r0,TRAP(r1)
 	addi	r3,r1,STACK_FRAME_OVERHEAD
 	bl	do_syscall_trace_enter
+	mr      r10,r3
 	lwz	r0,GPR0(r1)	/* Restore original registers */
 	lwz	r3,GPR3(r1)
 	lwz	r4,GPR4(r1)
@@ -285,6 +286,8 @@
 	lwz	r7,GPR7(r1)
 	lwz	r8,GPR8(r1)
 	REST_NVGPRS(r1)
+	cmpwi   r10,0
+	bne-    ret_from_syscall
 	b	syscall_dotrace_cont
 
 syscall_exit_work:
diff -Naur linux-2.6.21/arch/um/include/kern_util.h linux-2.6.21-ptmulti-ptvm/arch/um/include/kern_util.h
--- linux-2.6.21/arch/um/include/kern_util.h	2007-04-26 05:08:32.000000000 +0200
+++ linux-2.6.21-ptmulti-ptvm/arch/um/include/kern_util.h	2008-05-18 20:53:51.000000000 +0200
@@ -67,7 +67,7 @@
 extern void paging_init(void);
 extern void init_flush_vm(void);
 extern void *syscall_sp(void *t);
-extern void syscall_trace(union uml_pt_regs *regs, int entryexit);
+extern int syscall_trace(union uml_pt_regs *regs, int entryexit);
 extern int hz(void);
 extern unsigned int do_IRQ(int irq, union uml_pt_regs *regs);
 extern int external_pid(void *t);
diff -Naur linux-2.6.21/arch/um/kernel/ptrace.c linux-2.6.21-ptmulti-ptvm/arch/um/kernel/ptrace.c
--- linux-2.6.21/arch/um/kernel/ptrace.c	2007-04-26 05:08:32.000000000 +0200
+++ linux-2.6.21-ptmulti-ptvm/arch/um/kernel/ptrace.c	2008-05-18 21:36:22.000000000 +0200
@@ -83,6 +83,12 @@
                 ret = poke_user(child, addr, data);
                 break;
 
+	case PTRACE_SYSVM:
+		if (addr == PTRACE_VM_TEST) {
+			ret = PTRACE_VM_MASK;
+			break;
+		}
+
 	case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 	case PTRACE_CONT: { /* restart after signal. */
 		ret = -EIO;
@@ -90,11 +96,17 @@
 			break;
 
                 set_singlestepping(child, 0);
-		if (request == PTRACE_SYSCALL) {
-			set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+		child->ptrace &= ~PT_VM_MASK;
+		if (request == PTRACE_CONT) {
+			clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 		}
 		else {
-			clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+			set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+			if (request == PTRACE_SYSVM) {
+				/* set PT_VM_SKIPCALL and PT_VM_SKIPEXIT by
+				 * one operation */
+				child->ptrace |= (addr & PTRACE_VM_MASK) << 28;
+			}
 		}
 		child->exit_code = data;
 		wake_up_process(child);
@@ -275,7 +287,7 @@
 /* XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
  * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
  */
-void syscall_trace(union uml_pt_regs *regs, int entryexit)
+int syscall_trace(union uml_pt_regs *regs, int entryexit)
 {
 	int is_singlestep = (current->ptrace & PT_DTRACE) && entryexit;
 	int tracesysgood;
@@ -297,10 +309,13 @@
 		send_sigtrap(current, regs, 0);
 
 	if (!test_thread_flag(TIF_SYSCALL_TRACE))
-		return;
+		return 0;
 
 	if (!(current->ptrace & PT_PTRACED))
-		return;
+		return 0;
+
+	if (entryexit && (current->ptrace & PT_VM_SKIPEXIT))
+		return 0;
 
 	/* the 0x80 provides a way for the tracing parent to distinguish
 	   between a syscall stop and SIGTRAP delivery */
@@ -318,4 +333,8 @@
 		send_sig(current->exit_code, current, 1);
 		current->exit_code = 0;
 	}
+	if (!entryexit && (current->ptrace & PT_VM_SKIPCALL))
+		return 1;
+	else
+		return 0;
 }
diff -Naur linux-2.6.21/arch/um/kernel/skas/syscall.c linux-2.6.21-ptmulti-ptvm/arch/um/kernel/skas/syscall.c
--- linux-2.6.21/arch/um/kernel/skas/syscall.c	2007-04-26 05:08:32.000000000 +0200
+++ linux-2.6.21-ptmulti-ptvm/arch/um/kernel/skas/syscall.c	2008-05-18 20:57:03.000000000 +0200
@@ -18,8 +18,9 @@
 	struct pt_regs *regs = container_of(r, struct pt_regs, regs);
 	long result;
 	int syscall;
+	int skip_call;
 
-	syscall_trace(r, 0);
+	skip_call=syscall_trace(r, 0);
 
 	current->thread.nsyscalls++;
 	nsyscalls++;
@@ -32,12 +33,14 @@
 	 *     gcc version 4.0.1 20050727 (Red Hat 4.0.1-5)
 	 * in case it's a compiler bug.
 	 */
+	if (skip_call==0) {
 	syscall = UPT_SYSCALL_NR(r);
 	if((syscall >= NR_syscalls) || (syscall < 0))
 		result = -ENOSYS;
 	else result = EXECUTE_SYSCALL(syscall, regs);
 
 	REGS_SET_SYSCALL_RETURN(r->skas.regs, result);
+	}
 
 	syscall_trace(r, 1);
 }
diff -Naur linux-2.6.21/arch/um/kernel/tt/syscall_kern.c linux-2.6.21-ptmulti-ptvm/arch/um/kernel/tt/syscall_kern.c
--- linux-2.6.21/arch/um/kernel/tt/syscall_kern.c	2007-04-26 05:08:32.000000000 +0200
+++ linux-2.6.21-ptmulti-ptvm/arch/um/kernel/tt/syscall_kern.c	2008-05-18 20:57:35.000000000 +0200
@@ -21,16 +21,18 @@
 	void *sc;
 	long result;
 	int syscall;
+	int skip_call;
 
 	sc = UPT_SC(&regs->regs);
 	SC_START_SYSCALL(sc);
 
 	syscall = UPT_SYSCALL_NR(&regs->regs);
-	syscall_trace(&regs->regs, 0);
+	skip_call=syscall_trace(&regs->regs, 0);
 
 	current->thread.nsyscalls++;
 	nsyscalls++;
 
+	if (skip_call==0) {
 	if((syscall >= NR_syscalls) || (syscall < 0))
 		result = -ENOSYS;
 	else result = EXECUTE_SYSCALL(syscall, regs);
@@ -41,6 +43,7 @@
 	UPT_SC(&regs->regs) = sc;
 
 	SC_SET_SYSCALL_RETURN(sc, result);
+	}
 
 	syscall_trace(&regs->regs, 1);
 }
diff -Naur linux-2.6.21/include/linux/ptrace.h linux-2.6.21-ptmulti-ptvm/include/linux/ptrace.h
--- linux-2.6.21/include/linux/ptrace.h	2007-04-26 05:08:32.000000000 +0200
+++ linux-2.6.21-ptmulti-ptvm/include/linux/ptrace.h	2008-05-18 20:59:00.000000000 +0200
@@ -20,6 +20,7 @@
 #define PTRACE_DETACH		  17
 
 #define PTRACE_SYSCALL		  24
+#define PTRACE_SYSVM		  33
 
 /* 0x4200-0x4300 are reserved for architecture-independent additions.  */
 #define PTRACE_SETOPTIONS	0x4200
@@ -27,6 +28,18 @@
 #define PTRACE_GETSIGINFO	0x4202
 #define PTRACE_SETSIGINFO	0x4203
 
+#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
@@ -46,6 +59,12 @@
 #define PTRACE_EVENT_VFORK_DONE	5
 #define PTRACE_EVENT_EXIT	6
 
+/* options for PTRACE_SYSVM */
+#define PTRACE_VM_TEST		0x80000000
+#define PTRACE_VM_SKIPCALL	1
+#define PTRACE_VM_SKIPEXIT	2
+#define PTRACE_VM_MASK		0x00000003
+
 #include <asm/ptrace.h>
 
 #ifdef __KERNEL__
@@ -69,6 +88,10 @@
 #define PT_TRACE_EXIT	0x00000200
 #define PT_ATTACHED	0x00000400	/* parent != real_parent */
 
+#define PT_VM_SKIPCALL	0x10000000
+#define PT_VM_SKIPEXIT	0x20000000
+#define PT_VM_MASK	0x30000000
+
 #define PT_TRACE_MASK	0x000003f4
 
 /* single stepping state bits (used on ARM and PA-RISC) */
@@ -85,6 +108,7 @@
 extern struct task_struct *ptrace_get_task_struct(pid_t pid);
 extern int ptrace_traceme(void);
 extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
+extern int ptrace_readstringdata(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 int ptrace_detach(struct task_struct *, unsigned int);
diff -Naur linux-2.6.21/kernel/ptrace.c linux-2.6.21-ptmulti-ptvm/kernel/ptrace.c
--- linux-2.6.21/kernel/ptrace.c	2007-04-26 05:08:32.000000000 +0200
+++ linux-2.6.21-ptmulti-ptvm/kernel/ptrace.c	2008-05-18 20:46:53.000000000 +0200
@@ -2,6 +2,7 @@
  * linux/kernel/ptrace.c
  *
  * (C) Copyright 1999 Linus Torvalds
+ * PTRACE_MULTI support 2006 Renzo Davoli 
  *
  * Common interfaces for "ptrace()" which we do not want
  * to continually duplicate across every architecture.
@@ -241,54 +242,90 @@
 	return 0;
 }
 
-int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
+/*
+ * Access another process' address space to/from user space
+ * Do not walk the page table directly, use get_user_pages
+ */
+static int access_process_vm_user(struct task_struct *tsk, unsigned long addr, char __user *ubuf, int len, int write, int string)
 {
-	int copied = 0;
+	struct mm_struct *mm;
+	struct vm_area_struct *vma;
+	struct page *page;
+	char *buf;
+	unsigned long old_addr = addr;
 
-	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;
+	mm = get_task_mm(tsk);
+	if (!mm)
+		return 0;
+
+	buf=kmalloc(PAGE_SIZE, GFP_KERNEL);
+	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;
+			}
+			__copy_to_user(ubuf,buf,bytes);
 		}
-		if (copy_to_user(dst, buf, retval))
-			return -EFAULT;
-		copied += retval;
-		src += retval;
-		dst += retval;
-		len -= retval;			
+		kunmap(page);
+		page_cache_release(page);
+		len -= bytes;
+		ubuf += bytes;
+		addr += bytes;
 	}
-	return copied;
+	up_read(&mm->mmap_sem);
+	mmput(mm);
+
+	kfree(buf);
+	return addr - old_addr;
 }
 
-int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
+int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
 {
-	int copied = 0;
+	if (!access_ok(VERIFY_WRITE, dst ,len))
+		return -EIO;
+	return access_process_vm_user(tsk, src, dst, len, 0, 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;
+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);
+}
+
+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 int ptrace_setoptions(struct task_struct *child, long data)
@@ -447,6 +484,53 @@
 	return child;
 }
 
+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 ;
+		__copy_from_user(&pm, (struct ptrace_multi __user *)addr, sizeof(struct ptrace_multi));
+		len = pm.length;
+		switch (pm.request) {
+			case PTRACE_PEEKTEXT:
+			case PTRACE_PEEKDATA:
+			case PTRACE_PEEKUSR:
+				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_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));
+				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;
+}
+
 #ifndef __ARCH_SYS_PTRACE
 asmlinkage long sys_ptrace(long request, long pid, long addr, long data)
 {
@@ -477,6 +561,9 @@
 	if (ret < 0)
 		goto out_put_task_struct;
 
+	if (request == PTRACE_MULTI) 
+		ret = multi_ptrace(child, request, addr, data);
+	else
 	ret = arch_ptrace(child, request, addr, data);
 	if (ret < 0)
 		goto out_put_task_struct;