On Wed, Jan 23, 2019 at 07:33:05AM +0100, Greg Kroah-Hartman wrote: > On Wed, Jan 23, 2019 at 09:11:41AM +0900, Masami Hiramatsu wrote: > > On Tue, 22 Jan 2019 16:21:44 +0100 > > Greg Kroah-Hartman <[email protected]> wrote: > > > > > When calling debugfs functions, there is no need to ever check the > > > return value. The function can work or not, but the code logic should > > > never do something different based on this. > > > > Ah, OK. It simplifies the code. But I have a question below, > > > > > > > > Cc: Masami Hiramatsu <[email protected]> > > > Cc: Kees Cook <[email protected]> > > > Cc: Josef Bacik <[email protected]> > > > Cc: Thomas Gleixner <[email protected]> > > > Cc: "Naveen N. Rao" <[email protected]> > > > Cc: zhong jiang <[email protected]> > > > Signed-off-by: Greg Kroah-Hartman <[email protected]> > > > --- > > > kernel/fail_function.c | 23 +++++------------------ > > > 1 file changed, 5 insertions(+), 18 deletions(-) > > > > > > diff --git a/kernel/fail_function.c b/kernel/fail_function.c > > > index 17f75b545f66..afc779be5ebb 100644 > > > --- a/kernel/fail_function.c > > > +++ b/kernel/fail_function.c > > > @@ -152,20 +152,13 @@ static int fei_retval_get(void *data, u64 *val) > > > DEFINE_DEBUGFS_ATTRIBUTE(fei_retval_ops, fei_retval_get, fei_retval_set, > > > "%llx\n"); > > > > > > -static int fei_debugfs_add_attr(struct fei_attr *attr) > > > +static void fei_debugfs_add_attr(struct fei_attr *attr) > > > { > > > struct dentry *dir; > > > > > > dir = debugfs_create_dir(attr->kp.symbol_name, fei_debugfs_dir); > > > - if (!dir) > > > - return -ENOMEM; > > > - > > > - if (!debugfs_create_file("retval", 0600, dir, attr, &fei_retval_ops)) { > > > - debugfs_remove_recursive(dir); > > > - return -ENOMEM; > > > - } > > > > > > - return 0; > > > > Don't we need to check dir here? If above debugfs_create_dir() returns NULL, > > it seems we will create "retval" under root directory of debugfs. > > If NULL is returned, your system is out of memory and worse things are > about to happen :)
But you aren't the first to ask about this, I guess I should just return ENOMEM and then the follow-on files will not be created. I'll go make that change to the core of debugfs to help prevent this problem. thanks, greg k-h
