diff --git a/fs/proc/base.c b/fs/proc/base.c
index 837469a..e95878a 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -255,21 +255,30 @@ static int proc_pid_cmdline(struct task_struct *task, char * buffer)
 	int res = 0;
 	unsigned int len;
 	struct mm_struct *mm = get_task_mm(task);
+
 	if (!mm)
 		goto out;
+
+	/* The process was not constructed yet? */
 	if (!mm->arg_end)
 		goto out_mm;	/* Shh! No looking before we're done */
 
- 	len = mm->arg_end - mm->arg_start;
- 
+	down_read(&mm->arg_sem);
+	len = mm->arg_end - mm->arg_start;
 	if (len > PAGE_SIZE)
 		len = PAGE_SIZE;
- 
+
 	res = access_process_vm(task, mm->arg_start, buffer, len, 0);
 
-	// If the nul at the end of args has been overwritten, then
-	// assume application is using setproctitle(3).
-	if (res > 0 && buffer[res-1] != '\0' && len < PAGE_SIZE) {
+	if (mm->arg_end != mm->env_start)
+		/* PR_SET_PROCTITLE_AREA used */
+		res = strnlen(buffer, res);
+	else if (res > 0 && buffer[res-1] != '\0' && len < PAGE_SIZE) {
+		/*
+		 * If the nul at the end of args has been overwritten,
+		 * then assume application is using sendmail's
+		 * SPT_REUSEARGV style argv override.
+		 */
 		len = strnlen(buffer, res);
 		if (len < res) {
 		    res = len;
@@ -281,6 +290,8 @@ static int proc_pid_cmdline(struct task_struct *task, char * buffer)
 			res = strnlen(buffer, res);
 		}
 	}
+	up_read(&mm->arg_sem);
+
 out_mm:
 	mmput(mm);
 out:
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 84a524a..aff2e8d 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -236,6 +236,7 @@ struct mm_struct {
 	unsigned long stack_vm, reserved_vm, def_flags, nr_ptes;
 	unsigned long start_code, end_code, start_data, end_data;
 	unsigned long start_brk, brk, start_stack;
+	struct rw_semaphore arg_sem;
 	unsigned long arg_start, arg_end, env_start, env_end;
 
 	unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
diff --git a/include/linux/prctl.h b/include/linux/prctl.h
index 9311505..e80a11b 100644
--- a/include/linux/prctl.h
+++ b/include/linux/prctl.h
@@ -90,4 +90,8 @@
 
 #define PR_MCE_KILL	33
 
+
+/* Set process title memory area for setproctitle() */
+#define PR_SET_PROCTITLE_AREA 34
+
 #endif /* _LINUX_PRCTL_H */
diff --git a/kernel/fork.c b/kernel/fork.c
index 266c6af..014999c 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -459,6 +459,7 @@ static struct mm_struct * mm_init(struct mm_struct * mm, struct task_struct *p)
 	mm->cached_hole_size = ~0UL;
 	mm_init_aio(mm);
 	mm_init_owner(mm, p);
+	init_rwsem(&mm->arg_sem);
 
 	if (likely(!mm_alloc_pgd(mm))) {
 		mm->def_flags = 0;
diff --git a/kernel/sys.c b/kernel/sys.c
index 255475d..cd69a06 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1564,6 +1564,29 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
 			error = 0;
 			break;
 
+		case PR_SET_PROCTITLE_AREA: {
+			struct mm_struct *mm = current->mm;
+			unsigned long addr = arg2;
+			unsigned long len = arg3;
+			unsigned long end = arg2 + arg3;
+
+			if (len > PAGE_SIZE)
+				return -EINVAL;
+
+			if (addr >= end)
+				return -EINVAL;
+
+			if (!access_ok(VERIFY_READ, addr, len)) {
+				return -EFAULT;
+			}
+
+			down_write(&mm->arg_sem);
+			mm->arg_start = addr;
+			mm->arg_end = addr + len;
+			up_write(&mm->arg_sem);
+
+			return 0;
+		}
 		default:
 			error = -EINVAL;
 			break;