diff -purN linux-2.4.20/arch/i386/kernel/process.c linux/arch/i386/kernel/process.c
--- linux-2.4.20/arch/i386/kernel/process.c	2003-03-13 20:57:06.000000000 +0100
+++ linux/arch/i386/kernel/process.c	2003-03-13 20:57:57.000000000 +0100
@@ -503,7 +503,7 @@ __asm__(".align 4\n"
 /*
  * Create a kernel thread
  */
-int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
+int arch_kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 {
 	struct task_struct *p;
 	struct pt_regs regs;
diff -purN linux-2.4.20/fs/exec.c linux/fs/exec.c
--- linux-2.4.20/fs/exec.c	2003-03-13 20:57:03.000000000 +0100
+++ linux/fs/exec.c	2003-03-13 20:59:12.000000000 +0100
@@ -712,8 +712,10 @@ int flush_old_exec(struct linux_binprm *
 
 	current->sas_ss_sp = current->sas_ss_size = 0;
 
-	if (current->euid == current->uid && current->egid == current->gid)
+	if (current->euid == current->uid && current->egid == current->gid) {
 		current->mm->dumpable = 1;
+		current->task_dumpable = 1;
+	}
 	name = bprm->filename;
 	for (i=0; (ch = *(name++)) != '\0';) {
 		if (ch == '/')
@@ -1254,6 +1256,8 @@ int do_coredump(long signr, int exit_cod
 		up_write(&mm->mmap_sem);
 		goto fail;
 	}
+	if (!is_dumpable(current))
+                goto fail;                	
 	mm->dumpable = 0;
 	init_completion(&mm->core_done);
 	current->signal->group_exit = 1;
diff -purN linux-2.4.20/include/asm-i386/processor.h linux/include/asm-i386/processor.h
--- linux-2.4.20/include/asm-i386/processor.h	2003-03-13 20:57:04.000000000 +0100
+++ linux/include/asm-i386/processor.h	2003-03-13 20:57:59.000000000 +0100
@@ -447,7 +447,7 @@ extern void release_thread(struct task_s
 /*
  * create a kernel thread without removing it from tasklists
  */
-extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
+extern int arch_kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
 
 /* Copy and release all segment info associated with a VM
  * Unusable due to lack of error handling, use {init_new,destroy}_context
diff -purN linux-2.4.20/include/linux/sched.h linux/include/linux/sched.h
--- linux-2.4.20/include/linux/sched.h	2003-03-13 20:57:04.000000000 +0100
+++ linux/include/linux/sched.h	2003-03-13 21:03:58.000000000 +0100
@@ -426,6 +426,7 @@ struct task_struct {
 	/* ??? */
 	unsigned long personality;
 	int did_exec:1;
+	unsigned task_dumpable:1;
 	pid_t pid;
 	pid_t pgrp;
 	pid_t tty_old_pgrp;
@@ -557,6 +558,8 @@ struct task_struct {
 #define PT_TRACE_EXIT   0x00000200
 #define PT_DTRACE	0x00000400      /* delayed trace (used on m68k, i386) */
 
+#define is_dumpable(tsk)	((tsk)->task_dumpable && (tsk)->mm->dumpable)
+
 /*
  * Limit the stack by to some sane default: root can always
  * increase this limit if needed..  8MB seems reasonable.
@@ -901,6 +904,8 @@ extern void kick_if_running(task_t * p);
 #define wait_task_inactive(p) do {} while (0)
 #define kick_if_running(p) do {} while (0)
 #endif
+extern long kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
+
 
 #define __wait_event(wq, condition) 					\
 do {									\
diff -purN linux-2.4.20/kernel/fork.c linux/kernel/fork.c
--- linux-2.4.20/kernel/fork.c	2003-03-13 20:57:03.000000000 +0100
+++ linux/kernel/fork.c	2003-03-13 20:57:59.000000000 +0100
@@ -32,6 +32,7 @@
 #include <asm/pgalloc.h>
 #include <asm/uaccess.h>
 #include <asm/mmu_context.h>
+#include <asm/processor.h>
 
 static kmem_cache_t *task_struct_cachep;
 
@@ -649,6 +650,31 @@ asmlinkage int sys_set_tid_address(int *
 	return current->pid;
 }
 
+long kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
+{
+	struct task_struct *task = current;
+	unsigned old_task_dumpable;
+	long ret;
+
+	/* lock out any potential ptracer */
+	task_lock(task);
+	if (task->ptrace) {
+		task_unlock(task);
+		return -EPERM;
+	}
+
+	old_task_dumpable = task->task_dumpable;
+	task->task_dumpable = 0;
+	task_unlock(task);
+
+	ret = arch_kernel_thread(fn, arg, flags);
+
+	/* never reached in child process, only in parent */
+	current->task_dumpable = old_task_dumpable;
+
+	return ret;
+}
+
 /*
  * This creates a new process as a copy of the old one,
  * but does not actually start it yet.
diff -purN linux-2.4.20/kernel/ptrace.c linux/kernel/ptrace.c
--- linux-2.4.20/kernel/ptrace.c	2003-03-13 20:57:03.000000000 +0100
+++ linux/kernel/ptrace.c	2003-03-13 21:02:41.000000000 +0100
@@ -60,6 +60,10 @@ void __ptrace_unlink(task_t *child)
  */
 int ptrace_check_attach(struct task_struct *child, int kill)
 {
+	mb();
+	if (!is_dumpable(child))
+		return -EPERM;
+
 	if (!(child->ptrace & PT_PTRACED))
 		return -ESRCH;
 
@@ -95,7 +99,7 @@ int ptrace_attach(struct task_struct *ta
  	    (current->gid != task->gid)) && !capable(CAP_SYS_PTRACE))
 		goto bad;
 	rmb();
-	if (!task->mm->dumpable && !capable(CAP_SYS_PTRACE))
+	if (!is_dumpable(task) && !capable(CAP_SYS_PTRACE))
 		goto bad;
 	/* the same process cannot be attached many times */
 	if (task->ptrace & PT_PTRACED)
@@ -149,12 +153,14 @@ int ptrace_detach(struct task_struct *ch
 
 int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
 {
-	struct mm_struct *mm;
+	struct mm_struct *mm = NULL;
 	struct vm_area_struct *vma;
 	struct page *page;
 	void *old_buf = buf;
 
-	mm = get_task_mm(tsk);
+	if (is_dumpable(tsk) && (&init_mm != mm))
+		mm = get_task_mm(tsk);
+	
 	if (!mm)
 		return 0;
 
diff -purN linux-2.4.20/kernel/sys.c linux/kernel/sys.c
--- linux-2.4.20/kernel/sys.c	2003-03-13 20:57:03.000000000 +0100
+++ linux/kernel/sys.c	2003-03-13 20:57:59.000000000 +0100
@@ -1319,7 +1319,7 @@ asmlinkage long sys_prctl(int option, un
 			error = put_user(current->pdeath_signal, (int *)arg2);
 			break;
 		case PR_GET_DUMPABLE:
-			if (current->mm->dumpable)
+			if (is_dumpable(current))
 				error = 1;
 			break;
 		case PR_SET_DUMPABLE:
@@ -1327,7 +1327,8 @@ asmlinkage long sys_prctl(int option, un
 				error = -EINVAL;
 				break;
 			}
-			current->mm->dumpable = arg2;
+			if (is_dumpable(current))
+				current->mm->dumpable = arg2;
 			break;
 
 		case PR_SET_UNALIGN: