diff --git a/fs/proc/base.c b/fs/proc/base.c
index e665097c1da5aa87549fc50a249555441832f80d..4f764c2ac1a53db75c7c116cdb3bd4b45074c647 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -953,6 +953,7 @@ static ssize_t environ_read(struct file *file, char __user *buf,
 	unsigned long src = *ppos;
 	int ret = 0;
 	struct mm_struct *mm = file->private_data;
+	unsigned long env_start, env_end;
 
 	if (!mm)
 		return 0;
@@ -964,19 +965,25 @@ static ssize_t environ_read(struct file *file, char __user *buf,
 	ret = 0;
 	if (!atomic_inc_not_zero(&mm->mm_users))
 		goto free;
+
+	down_read(&mm->mmap_sem);
+	env_start = mm->env_start;
+	env_end = mm->env_end;
+	up_read(&mm->mmap_sem);
+
 	while (count > 0) {
 		size_t this_len, max_len;
 		int retval;
 
-		if (src >= (mm->env_end - mm->env_start))
+		if (src >= (env_end - env_start))
 			break;
 
-		this_len = mm->env_end - (mm->env_start + src);
+		this_len = env_end - (env_start + src);
 
 		max_len = min_t(size_t, PAGE_SIZE, count);
 		this_len = min(max_len, this_len);
 
-		retval = access_remote_vm(mm, (mm->env_start + src),
+		retval = access_remote_vm(mm, (env_start + src),
 			page, this_len, 0);
 
 		if (retval <= 0) {
diff --git a/mm/util.c b/mm/util.c
index 6d1f9200f74e794c403ec687bae513e4f6e40700..c108a6542d05d3e1c880c1f6ab540ced62156e54 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -476,17 +476,25 @@ int get_cmdline(struct task_struct *task, char *buffer, int buflen)
 	int res = 0;
 	unsigned int len;
 	struct mm_struct *mm = get_task_mm(task);
+	unsigned long arg_start, arg_end, env_start, env_end;
 	if (!mm)
 		goto out;
 	if (!mm->arg_end)
 		goto out_mm;	/* Shh! No looking before we're done */
 
-	len = mm->arg_end - mm->arg_start;
+	down_read(&mm->mmap_sem);
+	arg_start = mm->arg_start;
+	arg_end = mm->arg_end;
+	env_start = mm->env_start;
+	env_end = mm->env_end;
+	up_read(&mm->mmap_sem);
+
+	len = arg_end - arg_start;
 
 	if (len > buflen)
 		len = buflen;
 
-	res = access_process_vm(task, mm->arg_start, buffer, len, 0);
+	res = access_process_vm(task, arg_start, buffer, len, 0);
 
 	/*
 	 * If the nul at the end of args has been overwritten, then
@@ -497,10 +505,10 @@ int get_cmdline(struct task_struct *task, char *buffer, int buflen)
 		if (len < res) {
 			res = len;
 		} else {
-			len = mm->env_end - mm->env_start;
+			len = env_end - env_start;
 			if (len > buflen - res)
 				len = buflen - res;
-			res += access_process_vm(task, mm->env_start,
+			res += access_process_vm(task, env_start,
 						 buffer+res, len, 0);
 			res = strnlen(buffer, res);
 		}