Char/Misc fixes for 4.15-rc6

Here are six small fixes of some of the char/misc drivers that have been
 sent in to resolve reported issues.
 
 Nothing major, a binder use-after-free fix, some thunderbolt bugfixes, a
 hyper-v bugfix, and an nvmem driver fix.  All of these have been in
 linux-next with no reported issues for a while.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'char-misc-4.15-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

Pull char/misc fixes from Greg KH:
 "Here are six small fixes of some of the char/misc drivers that have
  been sent in to resolve reported issues.

  Nothing major, a binder use-after-free fix, some thunderbolt bugfixes,
  a hyper-v bugfix, and an nvmem driver fix. All of these have been in
  linux-next with no reported issues for a while"

* tag 'char-misc-4.15-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  nvmem: meson-mx-efuse: fix reading from an offset other than 0
  binder: fix proc->files use-after-free
  vmbus: unregister device_obj->channels_kset
  thunderbolt: Mask ring interrupt properly when polling starts
  MAINTAINERS: Add thunderbolt.rst to the Thunderbolt driver entry
  thunderbolt: Make pathname to force_power shorter

Documentation/admin-guide/thunderbolt.rst

@@ -230,7 +230,7 @@ If supported by your machine this will be exposed by the WMI bus with
 a sysfs attribute called "force_power".
 
 For example the intel-wmi-thunderbolt driver exposes this attribute in:
-  /sys/devices/platform/PNP0C14:00/wmi_bus/wmi_bus-PNP0C14:00/86CCFD48-205E-4A77-9C48-2021CBEDE341/force_power
+  /sys/bus/wmi/devices/86CCFD48-205E-4A77-9C48-2021CBEDE341/force_power
 
   To force the power to on, write 1 to this attribute file.
   To disable force power, write 0 to this attribute file.

MAINTAINERS

@@ -13491,6 +13491,7 @@ M:	Mika Westerberg <mika.westerberg@linux.intel.com>
 M:	Yehezkel Bernat <yehezkel.bernat@intel.com>
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/westeri/thunderbolt.git
 S:	Maintained
+F:	Documentation/admin-guide/thunderbolt.rst
 F:	drivers/thunderbolt/
 F:	include/linux/thunderbolt.h
 

drivers/android/binder.c

@@ -482,7 +482,8 @@ enum binder_deferred_state {
  * @tsk                   task_struct for group_leader of process
  *                        (invariant after initialized)
  * @files                 files_struct for process
- *                        (invariant after initialized)
+ *                        (protected by @files_lock)
+ * @files_lock            mutex to protect @files
  * @deferred_work_node:   element for binder_deferred_list
  *                        (protected by binder_deferred_lock)
  * @deferred_work:        bitmap of deferred work to perform
@@ -530,6 +531,7 @@ struct binder_proc {
 	int pid;
 	struct task_struct *tsk;
 	struct files_struct *files;
+	struct mutex files_lock;
 	struct hlist_node deferred_work_node;
 	int deferred_work;
 	bool is_dead;
@@ -877,20 +879,26 @@ static void binder_inc_node_tmpref_ilocked(struct binder_node *node);
 
 static int task_get_unused_fd_flags(struct binder_proc *proc, int flags)
 {
-	struct files_struct *files = proc->files;
 	unsigned long rlim_cur;
 	unsigned long irqs;
+	int ret;
 
-	if (files == NULL)
-		return -ESRCH;
-
-	if (!lock_task_sighand(proc->tsk, &irqs))
-		return -EMFILE;
-
+	mutex_lock(&proc->files_lock);
+	if (proc->files == NULL) {
+		ret = -ESRCH;
+		goto err;
+	}
+	if (!lock_task_sighand(proc->tsk, &irqs)) {
+		ret = -EMFILE;
+		goto err;
+	}
 	rlim_cur = task_rlimit(proc->tsk, RLIMIT_NOFILE);
 	unlock_task_sighand(proc->tsk, &irqs);
 
-	return __alloc_fd(files, 0, rlim_cur, flags);
+	ret = __alloc_fd(proc->files, 0, rlim_cur, flags);
+err:
+	mutex_unlock(&proc->files_lock);
+	return ret;
 }
 
 /*
@@ -899,8 +907,10 @@ static int task_get_unused_fd_flags(struct binder_proc *proc, int flags)
 static void task_fd_install(
 	struct binder_proc *proc, unsigned int fd, struct file *file)
 {
+	mutex_lock(&proc->files_lock);
 	if (proc->files)
 		__fd_install(proc->files, fd, file);
+	mutex_unlock(&proc->files_lock);
 }
 
 /*
@@ -910,9 +920,11 @@ static long task_close_fd(struct binder_proc *proc, unsigned int fd)
 {
 	int retval;
 
-	if (proc->files == NULL)
-		return -ESRCH;
-
+	mutex_lock(&proc->files_lock);
+	if (proc->files == NULL) {
+		retval = -ESRCH;
+		goto err;
+	}
 	retval = __close_fd(proc->files, fd);
 	/* can't restart close syscall because file table entry was cleared */
 	if (unlikely(retval == -ERESTARTSYS ||
@@ -920,7 +932,8 @@ static long task_close_fd(struct binder_proc *proc, unsigned int fd)
 		     retval == -ERESTARTNOHAND ||
 		     retval == -ERESTART_RESTARTBLOCK))
 		retval = -EINTR;
-
+err:
+	mutex_unlock(&proc->files_lock);
 	return retval;
 }
 
@@ -4627,7 +4640,9 @@ static int binder_mmap(struct file *filp, struct vm_area_struct *vma)
 	ret = binder_alloc_mmap_handler(&proc->alloc, vma);
 	if (ret)
 		return ret;
+	mutex_lock(&proc->files_lock);
 	proc->files = get_files_struct(current);
+	mutex_unlock(&proc->files_lock);
 	return 0;
 
 err_bad_arg:
@@ -4651,6 +4666,7 @@ static int binder_open(struct inode *nodp, struct file *filp)
 	spin_lock_init(&proc->outer_lock);
 	get_task_struct(current->group_leader);
 	proc->tsk = current->group_leader;
+	mutex_init(&proc->files_lock);
 	INIT_LIST_HEAD(&proc->todo);
 	proc->default_priority = task_nice(current);
 	binder_dev = container_of(filp->private_data, struct binder_device,
@@ -4903,9 +4919,11 @@ static void binder_deferred_func(struct work_struct *work)
 
 		files = NULL;
 		if (defer & BINDER_DEFERRED_PUT_FILES) {
+			mutex_lock(&proc->files_lock);
 			files = proc->files;
 			if (files)
 				proc->files = NULL;
+			mutex_unlock(&proc->files_lock);
 		}
 
 		if (defer & BINDER_DEFERRED_FLUSH)

drivers/hv/vmbus_drv.c

@@ -1378,6 +1378,8 @@ void vmbus_device_unregister(struct hv_device *device_obj)
 	pr_debug("child device %s unregistered\n",
 		dev_name(&device_obj->device));
 
+	kset_unregister(device_obj->channels_kset);
+
 	/*
 	 * Kick off the process of unregistering the device.
 	 * This will call vmbus_remove() and eventually vmbus_device_release()

drivers/nvmem/meson-mx-efuse.c

@@ -156,8 +156,8 @@ static int meson_mx_efuse_read(void *context, unsigned int offset,
 				 MESON_MX_EFUSE_CNTL1_AUTO_RD_ENABLE,
 				 MESON_MX_EFUSE_CNTL1_AUTO_RD_ENABLE);
 
-	for (i = offset; i < offset + bytes; i += efuse->config.word_size) {
-		addr = i / efuse->config.word_size;
+	for (i = 0; i < bytes; i += efuse->config.word_size) {
+		addr = (offset + i) / efuse->config.word_size;
 
 		err = meson_mx_efuse_read_addr(efuse, addr, &tmp);
 		if (err)

drivers/thunderbolt/nhi.c

@@ -339,7 +339,7 @@ static void __ring_interrupt(struct tb_ring *ring)
 		return;
 
 	if (ring->start_poll) {
-		__ring_interrupt_mask(ring, false);
+		__ring_interrupt_mask(ring, true);
 		ring->start_poll(ring->poll_data);
 	} else {
 		schedule_work(&ring->work);