From: Steven Rostedt (Google) Date: Tue, 6 Feb 2024 12:09:33 +0000 (-0500) Subject: eventfs: Do not allow NULL parent to eventfs_start_creating() X-Git-Tag: v6.6.18~55 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=29bb70cad6685839f4e5d0b97c4d7ffc8639cb9d;p=thirdparty%2Fkernel%2Fstable.git eventfs: Do not allow NULL parent to eventfs_start_creating() commit fc4561226feaad5fcdcb55646c348d77b8ee69c5 upstream. The eventfs directory is dynamically created via the meta data supplied by the existing trace events. All files and directories in eventfs has a parent. Do not allow NULL to be passed into eventfs_start_creating() as the parent because that should never happen. Warn if it does. Link: https://lkml.kernel.org/r/20231121231112.693841807@goodmis.org Cc: Masami Hiramatsu Cc: Mark Rutland Cc: Andrew Morton Reviewed-by: Josef Bacik Signed-off-by: Steven Rostedt (Google) Signed-off-by: Greg Kroah-Hartman --- diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c index 34ffb2f8114e0..b9ed8db4f6b93 100644 --- a/fs/tracefs/inode.c +++ b/fs/tracefs/inode.c @@ -509,20 +509,15 @@ struct dentry *eventfs_start_creating(const char *name, struct dentry *parent) struct dentry *dentry; int error; + /* Must always have a parent. */ + if (WARN_ON_ONCE(!parent)) + return ERR_PTR(-EINVAL); + error = simple_pin_fs(&trace_fs_type, &tracefs_mount, &tracefs_mount_count); if (error) return ERR_PTR(error); - /* - * If the parent is not specified, we create it in the root. - * We need the root dentry to do this, which is in the super - * block. A pointer to that is in the struct vfsmount that we - * have around. - */ - if (!parent) - parent = tracefs_mount->mnt_root; - if (unlikely(IS_DEADDIR(parent->d_inode))) dentry = ERR_PTR(-ENOENT); else