From 7bc68c67d21e9cfcf78989c808632d236e6c02d9 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Thu, 18 Feb 2021 11:08:18 +0100 Subject: [PATCH] debugfs: do not attempt to create a new file before the filesystem is initalized commit 56348560d495d2501e87db559a61de717cd3ab02 upstream. 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. Cc: "Rafael J. Wysocki" Cc: stable Reported-by: Michael Walle Reported-by: Marc Zyngier Link: https://lore.kernel.org/r/20210218100818.3622317-2-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman --- fs/debugfs/inode.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c index bbeb563c..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)) -- 2.7.4