Merge tag 'char-misc-4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

Pull char/misc driver updates from Greg KH:
 "Here is the big pull request for char/misc drivers for 4.16-rc1.

  There's a lot of stuff in here. Three new driver subsystems were added
  for various types of hardware busses:

   - siox
   - slimbus
   - soundwire

  as well as a new vboxguest subsystem for the VirtualBox hypervisor
  drivers.

  There's also big updates from the FPGA subsystem, lots of Android
  binder fixes, the usual handful of hyper-v updates, and lots of other
  smaller driver updates.

  All of these have been in linux-next for a long time, with no reported
  issues"

* tag 'char-misc-4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (155 commits)
  char: lp: use true or false for boolean values
  android: binder: use VM_ALLOC to get vm area
  android: binder: Use true and false for boolean values
  lkdtm: fix handle_irq_event symbol for INT_HW_IRQ_EN
  EISA: Delete error message for a failed memory allocation in eisa_probe()
  EISA: Whitespace cleanup
  misc: remove AVR32 dependencies
  virt: vbox: Add error mapping for VERR_INVALID_NAME and VERR_NO_MORE_FILES
  soundwire: Fix a signedness bug
  uio_hv_generic: fix new type mismatch warnings
  uio_hv_generic: fix type mismatch warnings
  auxdisplay: img-ascii-lcd: add missing MODULE_DESCRIPTION/AUTHOR/LICENSE
  uio_hv_generic: add rescind support
  uio_hv_generic: check that host supports monitor page
  uio_hv_generic: create send and receive buffers
  uio: document uio_hv_generic regions
  doc: fix documentation about uio_hv_generic
  vmbus: add monitor_id and subchannel_id to sysfs per channel
  vmbus: fix ABI documentation
  uio_hv_generic: use ISR callback method
  ...

1 files changed, 22 insertions, 5 deletions

diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 6aefe5370e5b..052011bcf100 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -107,6 +107,8 @@ static ssize_t read_mem(struct file *file, char __user *buf,
 	phys_addr_t p = *ppos;
 	ssize_t read, sz;
 	void *ptr;
+	char *bounce;
+	int err;
 
 	if (p != *ppos)
 		return 0;
@@ -129,15 +131,22 @@ static ssize_t read_mem(struct file *file, char __user *buf,
 	}
 #endif
 
+	bounce = kmalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!bounce)
+		return -ENOMEM;
+
 	while (count > 0) {
 		unsigned long remaining;
 		int allowed;
 
 		sz = size_inside_page(p, count);
 
+		err = -EPERM;
 		allowed = page_is_allowed(p >> PAGE_SHIFT);
 		if (!allowed)
-			return -EPERM;
+			goto failed;
+
+		err = -EFAULT;
 		if (allowed == 2) {
 			/* Show zeros for restricted memory. */
 			remaining = clear_user(buf, sz);
@@ -149,24 +158,32 @@ static ssize_t read_mem(struct file *file, char __user *buf,
 			 */
 			ptr = xlate_dev_mem_ptr(p);
 			if (!ptr)
-				return -EFAULT;
-
-			remaining = copy_to_user(buf, ptr, sz);
+				goto failed;
 
+			err = probe_kernel_read(bounce, ptr, sz);
 			unxlate_dev_mem_ptr(p, ptr);
+			if (err)
+				goto failed;
+
+			remaining = copy_to_user(buf, bounce, sz);
 		}
 
 		if (remaining)
-			return -EFAULT;
+			goto failed;
 
 		buf += sz;
 		p += sz;
 		count -= sz;
 		read += sz;
 	}
+	kfree(bounce);
 
 	*ppos += read;
 	return read;
+
+failed:
+	kfree(bounce);
+	return err;
 }
 
 static ssize_t write_mem(struct file *file, const char __user *buf,