From: Kees Cook <kees@kernel.org>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: Bill Wendling <morbo@google.com>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
"Matthew Wilcox (Oracle)" <willy@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
David Gow <david@davidgow.net>, Petr Mladek <pmladek@suse.com>,
Shuvam Pandey <shuvampandey1@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
nikitash.mariiaw@gmail.com, linux-kernel@vger.kernel.org,
linux-hardening@vger.kernel.org
Subject: Re: [PATCH v2 5/9] seq_buf: Add seq_buf_strlen()
Date: Sat, 19 Sep 2026 14:15:58 -0700 [thread overview]
Message-ID: <202609191326.4042FC4@keescook> (raw)
In-Reply-To: <2026091953-cherub-empty-ef35@gregkh>
On Sat, Sep 19, 2026 at 08:38:37AM +0100, Greg KH wrote:
> On Fri, Sep 18, 2026 at 05:27:03PM -0700, Kees Cook wrote:
> > +static inline size_t seq_buf_strlen(struct seq_buf *s)
> > +{
> > + if (WARN_ON(s->size == 0))
> > + return 0;
>
> Why WARN_ON()? Are you wanting to just mint new CVEs with this code
> path, do we not give out enough already? :)
>
> I can see returning 0, if it's empty, but isn't that a valid check for
> people to wish to know at times? Why crash the box? (remember about
> panic-on-warn being enabled in a few billion Linux instances...)
We have to figure out a line somewhere. :P Making a seq_buf with size 0
is a nonsense construction, but seq_buf_init is non-allocating, so
there's no feedback about setting it to size 0. We could move the WARN
to the init? I was just following the existing style here.
I'm happy to remove it.
--
Kees Cook
next prev parent reply other threads:[~2026-09-19 21:15 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-19 0:26 [PATCH v2 0/9] " Kees Cook
2026-09-19 0:26 ` [PATCH v2 1/9] seq_buf: Do not print an empty line from an overflowed seq_buf_do_printk() Kees Cook
2026-09-19 0:27 ` [PATCH v2 2/9] seq_buf: Do not pop from an overflowed seq_buf Kees Cook
2026-09-19 0:27 ` [PATCH v2 3/9] seq_buf: Copy what fits when seq_buf_puts() and seq_buf_putmem() overflow Kees Cook
2026-09-19 0:27 ` [PATCH v2 4/9] seq_buf: Clear what a writer did not claim when a seq_buf overflows Kees Cook
2026-09-19 0:27 ` [PATCH v2 5/9] seq_buf: Add seq_buf_strlen() Kees Cook
2026-09-19 7:38 ` Greg KH
2026-09-19 21:15 ` Kees Cook [this message]
2026-09-20 5:34 ` Greg KH
2026-09-19 0:27 ` [PATCH v2 6/9] seq_buf: Add seq_buf_init_append() Kees Cook
2026-09-19 0:27 ` [PATCH v2 7/9] powerpc/papr_scm: Return the string length from the sysfs show functions Kees Cook
2026-09-19 0:27 ` [PATCH v2 8/9] nvdimm: ndtest: Return the string length from flags_show() Kees Cook
2026-09-19 0:27 ` [PATCH v2 9/9] docs: core-api: Document the seq_buf API Kees Cook
2026-09-19 1:54 ` Randy Dunlap
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