From: "Steven Rostedt (Google)" rostedt@goodmis.org

The function tracefs_create_dir() was missing a lockdown check and was called by the RV code. This gave an inconsistent behavior of this function returning success while other tracefs functions failed. This caused the inode being freed by the wrong kmem_cache.

Link: https://lkml.kernel.org/r/20230905182711.692687042@goodmis.org Link: https://lore.kernel.org/all/202309050916.58201dc6-oliver.sang@intel.com/

Cc: stable@vger.kernel.org Cc: Masami Hiramatsu mhiramat@kernel.org Cc: Mark Rutland mark.rutland@arm.com Cc: Andrew Morton akpm@linux-foundation.org Cc: Ajay Kaher akaher@vmware.com Cc: Ching-lin Yu chinglinyu@google.com Fixes: bf8e602186ec4 ("tracing: Do not create tracefs files if tracefs lockdown is in effect") Reported-by: kernel test robot oliver.sang@intel.com Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org --- fs/tracefs/inode.c | 3 +++ 1 file changed, 3 insertions(+)

diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c index de5b72216b1a..3b8dd938b1c8 100644 --- a/fs/tracefs/inode.c +++ b/fs/tracefs/inode.c @@ -673,6 +673,9 @@ static struct dentry *__create_dir(const char *name, struct dentry *parent, */ struct dentry *tracefs_create_dir(const char *name, struct dentry *parent) { + if (security_locked_down(LOCKDOWN_TRACEFS)) + return NULL; + return __create_dir(name, parent, &simple_dir_inode_operations); }