[irqchip: irq/irqchip-next] debugfs: do not attempt to create a new file before the filesystem is initalized

[irqchip-bot for Greg Kroah-Hartman]

The following commit has been merged into the irq/irqchip-next branch of irqchip:

Commit-ID:     fb0757f54bc9259c4c67907fd97ca3ad109d3f6f
Gitweb:        https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms/fb0757f54bc9259c4c67907fd97ca3ad109d3f6f
Author:        Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
AuthorDate:    Thu, 18 Feb 2021 11:08:18 +01:00
Committer:     Marc Zyngier <maz@xxxxxxxxxx>
CommitterDate: Thu, 18 Feb 2021 11:39:18 

debugfs: do not attempt to create a new file before the filesystem is initalized

Some subsystems want to add debugfs files at early boot, way before
debugfs is initialized.  This seems to work somehow as the vfs layer
will not allow it to happen, but let's be explicit and test to ensure we
are properly up and running before allowing files to be created.

Reported-by: Michael Walle <michael@xxxxxxxx>
Reported-by: Marc Zyngier <maz@xxxxxxxxxx>
Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20210218100818.3622317-2-gregkh@xxxxxxxxxxxxxxxxxxx
---
 fs/debugfs/inode.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index bbeb563..86c7f04 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -318,6 +318,9 @@ static struct dentry *start_creating(const char *name, struct dentry *parent)
 	if (!(debugfs_allow & DEBUGFS_ALLOW_API))
 		return ERR_PTR(-EPERM);
 
+	if (!debugfs_initialized())
+		return ERR_PTR(-ENOENT);
+
 	pr_debug("creating file '%s'\n", name);
 
 	if (IS_ERR(parent))