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Commit f1f76f86 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Greg Kroah-Hartman
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devtmpfs: Convert dirlock to a mutex 



devtmpfs has a rw_lock dirlock which serializes delete_path and
create_path.

This code was obviously never tested with the usual set of debugging
facilities enabled. In the dirlock held sections the code calls:

 - vfs functions which take mutexes
 - kmalloc(, GFP_KERNEL)

In both code pathes the might sleep warning triggers and spams dmesg.

Convert the rw_lock to a mutex. There is no reason why this needs to
be a rwlock.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: stable <stable@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent f42ecb28

drivers/base/devtmpfs.c

+5 −7
Original line number Original line Diff line number Diff line
@@ -32,7 +32,7 @@ static int dev_mount = 1; 
static int dev_mount;

static int dev_mount;

#endif

#endif





static rwlock_t dirlock;

static DEFINE_MUTEX(dirlock);





static int __init mount_param(char *str)

static int __init mount_param(char *str)

{

{
@@ -93,7 +93,7 @@ static int create_path(const char *nodepath) 
{

{

	int err;

	int err;





	read_lock(&dirlock);

	mutex_lock(&dirlock);

	err = dev_mkdir(nodepath, 0755);

	err = dev_mkdir(nodepath, 0755);

	if (err == -ENOENT) {

	if (err == -ENOENT) {

		char *path;

		char *path;
@@ -117,7 +117,7 @@ static int create_path(const char *nodepath) 
		}

		}

		kfree(path);

		kfree(path);

	}

	}

	read_unlock(&dirlock);

	mutex_unlock(&dirlock);

	return err;

	return err;

}

}
@@ -229,7 +229,7 @@ static int delete_path(const char *nodepath) 
	if (!path)

	if (!path)

		return -ENOMEM;

		return -ENOMEM;





	write_lock(&dirlock);

	mutex_lock(&dirlock);

	for (;;) {

	for (;;) {

		char *base;

		char *base;
@@ -241,7 +241,7 @@ static int delete_path(const char *nodepath) 
		if (err)

		if (err)

			break;

			break;

	}

	}

	write_unlock(&dirlock);

	mutex_unlock(&dirlock);





	kfree(path);

	kfree(path);

	return err;

	return err;
@@ -352,8 +352,6 @@ int __init devtmpfs_init(void) 
	int err;

	int err;

	struct vfsmount *mnt;

	struct vfsmount *mnt;





	rwlock_init(&dirlock);



	err = register_filesystem(&dev_fs_type);

	err = register_filesystem(&dev_fs_type);

	if (err) {

	if (err) {

		printk(KERN_ERR "devtmpfs: unable to register devtmpfs "

		printk(KERN_ERR "devtmpfs: unable to register devtmpfs "