diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index a0a7ae705de8..d82b3b7658bd 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -3535,7 +3535,7 @@ static int cdrom_print_info(const char *header, int val, char *info,
 }
 
 static int cdrom_sysctl_info(struct ctl_table *ctl, int write,
-                           void __user *buffer, size_t *lenp, loff_t *ppos)
+                           void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int pos;
 	char *info = cdrom_sysctl_settings.info;
diff --git a/drivers/char/random.c b/drivers/char/random.c
index a7cf6aa65908..2a41b21623ae 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -2087,7 +2087,7 @@ static int proc_do_uuid(struct ctl_table *table, int write,
  * Return entropy available scaled to integral bits
  */
 static int proc_do_entropy(struct ctl_table *table, int write,
-			   void __user *buffer, size_t *lenp, loff_t *ppos)
+			   void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct ctl_table fake_table;
 	int entropy_count;
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 5b405f32971d..42c5128c7d1c 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -565,6 +565,10 @@ static ssize_t proc_sys_call_handler(struct file *filp, void __user *ubuf,
 	if (!table->proc_handler)
 		goto out;
 
+	/* don't even try if the size is too large */
+	if (count > KMALLOC_MAX_SIZE)
+		return -ENOMEM;
+
 	if (write) {
 		kbuf = memdup_user_nul(ubuf, count);
 		if (IS_ERR(kbuf)) {
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index dfbbf7a7208b..e339dac91ee6 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -342,9 +342,8 @@ static inline void arch_ftrace_set_direct_caller(struct pt_regs *regs,
 
 extern int stack_tracer_enabled;
 
-int stack_trace_sysctl(struct ctl_table *table, int write,
-		       void __user *buffer, size_t *lenp,
-		       loff_t *ppos);
+int stack_trace_sysctl(struct ctl_table *table, int write, void *buffer,
+		       size_t *lenp, loff_t *ppos);
 
 /* DO NOT MODIFY THIS VARIABLE DIRECTLY! */
 DECLARE_PER_CPU(int, disable_stack_tracer);
diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index e1476775769c..81ee17594c32 100644
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -392,13 +392,12 @@ void *neigh_seq_next(struct seq_file *, void *, loff_t *);
 void neigh_seq_stop(struct seq_file *, void *);
 
 int neigh_proc_dointvec(struct ctl_table *ctl, int write,
-			void __user *buffer, size_t *lenp, loff_t *ppos);
+			void *buffer, size_t *lenp, loff_t *ppos);
 int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,
-				void __user *buffer,
+				void *buffer,
 				size_t *lenp, loff_t *ppos);
 int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
-				   void __user *buffer,
-				   size_t *lenp, loff_t *ppos);
+				   void *buffer, size_t *lenp, loff_t *ppos);
 
 int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
 			  proc_handler *proc_handler);
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index c557f42a9397..98bba4764c52 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -515,9 +515,8 @@ static const struct file_operations stack_trace_filter_fops = {
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
 int
-stack_trace_sysctl(struct ctl_table *table, int write,
-		   void __user *buffer, size_t *lenp,
-		   loff_t *ppos)
+stack_trace_sysctl(struct ctl_table *table, int write, void *buffer,
+		   size_t *lenp, loff_t *ppos)
 {
 	int was_enabled;
 	int ret;
diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index b109cc8a6dd8..f93f8ace6c56 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -128,7 +128,7 @@ static int flow_limit_cpu_sysctl(struct ctl_table *table, int write,
 		return -ENOMEM;
 
 	if (write) {
-		ret = cpumask_parse_user(buffer, *lenp, mask);
+		ret = cpumask_parse(buffer, mask);
 		if (ret)
 			goto done;