devtmpfs: Convert dirlock to a mutex (f1f76f86) · Commits · 戴 / test

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:

Thomas Gleixner <tglx@linutronix.de> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: stable <stable@kernel.org> Signed-off-by:

Greg Kroah-Hartman <gregkh@suse.de>

drivers/base/devtmpfs.c

+5 −7

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

		static rwlock_t dirlock;
		static DEFINE_MUTEX(dirlock);

		static int __init mount_param(char *str)
		{
		@@ -93,7 +93,7 @@ static int create_path(const char *nodepath)
		{
		int err;

		read_lock(&dirlock);
		mutex_lock(&dirlock);
		err = dev_mkdir(nodepath, 0755);
		if (err == -ENOENT) {
		char *path;
		@@ -117,7 +117,7 @@ static int create_path(const char *nodepath)
		}
		kfree(path);
		}
		read_unlock(&dirlock);
		mutex_unlock(&dirlock);
		return err;
		}

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

		write_lock(&dirlock);
		mutex_lock(&dirlock);
		for (;;) {
		char *base;

		@@ -241,7 +241,7 @@ static int delete_path(const char *nodepath)
		if (err)
		break;
		}
		write_unlock(&dirlock);
		mutex_unlock(&dirlock);

		kfree(path);
		return err;
		@@ -352,8 +352,6 @@ int __init devtmpfs_init(void)
		int err;
		struct vfsmount *mnt;

		rwlock_init(&dirlock);

		err = register_filesystem(&dev_fs_type);
		if (err) {
		printk(KERN_ERR "devtmpfs: unable to register devtmpfs "

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