Re: [PATCH] bootconfig: remove unreachable index checks in xbc_verify_tree()

[Masami Hiramatsu (Google) <mhiramat@kernel.org>]

On Wed, 9 Sep 2026 00:34:35 +0900
Sang-Heon Jeon <ekffu200098@gmail.com> wrote:

> Hi,
> 
> On Tue, Sep 8, 2026 at 10:46 AM Masami Hiramatsu <mhiramat@kernel.org> wrote:
> >
> > On Sat,  5 Sep 2026 23:16:36 +0900
> > Sang-Heon Jeon <ekffu200098@gmail.com> wrote:
> >
> > > xbc_verify_tree() checks that every node's next and child are below
> > > xbc_node_num. Both fields store the index of an existing node, which
> > > is below xbc_node_num.
> >
> > This is a kind of foolpoof/defensive checking. (so I call it verify.)
> >
> > >
> > > So remove the checks.
> > >
> > > No functional change.
> >
> > Hmm, OK, I think we should decouple the logic/implementation
> > verification from runtime verification (e.g. wrong format)
> > and move the former to tools/bootconfig.
> >
> > Thank you,
> 
> Thanks for the review, Masami.
> 
> To make sure I understand, you mean moving the foolproof check after
> xbc_init() in tools/bootconfig?

Instead of just removing this, move this verification into tools/bootconfig.
(we still need verification of user given broken bootconfig.)
Let me handle it.

Thank you,

> 
> > >
> > > Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
> > > ---
> > >  lib/bootconfig.c | 13 +------------
> > >  1 file changed, 1 insertion(+), 12 deletions(-)
> > >
> > > diff --git a/lib/bootconfig.c b/lib/bootconfig.c
> > > index 89c88e359179..d383430637ee 100644
> > > --- a/lib/bootconfig.c
> > > +++ b/lib/bootconfig.c
> > > @@ -1005,7 +1005,7 @@ static int __init xbc_close_brace(char **k, char *n)
> > >
> > >  static int __init xbc_verify_tree(void)
> > >  {
> > > -     int i, depth;
> > > +     int depth;
> > >       size_t len, wlen;
> > >       struct xbc_node *n, *m;
> > >
> > > @@ -1022,17 +1022,6 @@ static int __init xbc_verify_tree(void)
> > >               return -ENOENT;
> > >       }
> > >
> > > -     for (i = 0; i < xbc_node_num; i++) {
> > > -             if (xbc_nodes[i].next >= xbc_node_num) {
> > > -                     return xbc_parse_error("No closing brace",
> > > -                             xbc_node_get_data(xbc_nodes + i));
> > > -             }
> > > -             if (xbc_nodes[i].child >= xbc_node_num) {
> > > -                     return xbc_parse_error("Broken child node",
> > > -                             xbc_node_get_data(xbc_nodes + i));
> > > -             }
> > > -     }
> > > -
> > >       /* Key tree limitation check */
> > >       n = &xbc_nodes[0];
> > >       depth = 1;
> > > --
> > > 2.43.0
> > >
> >
> >
> > --
> > Masami Hiramatsu (Google) <mhiramat@kernel.org>
> 
> Best regards,
> Sang-Heon Jeon


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>