From: Kees Cook <kees@kernel.org>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: "Bill Wendling" <morbo@google.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>,
"Jonathan Corbet" <corbet@lwn.net>,
"Sergey Senozhatsky" <senozhatsky@chromium.org>,
"Günther Noack" <gnoack@google.com>,
"Mickaël Salaün" <mic@digikod.net>,
"Masami Hiramatsu" <mhiramat@kernel.org>,
"Mathieu Desnoyers" <mathieu.desnoyers@efficios.com>,
"Jiri Kosina" <jikos@kernel.org>,
"Alexei Starovoitov" <ast@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"Andrii Nakryiko" <andrii@kernel.org>,
"Eduard Zingerman" <eddyz87@gmail.com>,
"Kumar Kartikeya Dwivedi" <memxor@gmail.com>,
"Martin KaFai Lau" <martin.lau@linux.dev>,
"Song Liu" <song@kernel.org>,
"Yonghong Song" <yonghong.song@linux.dev>,
"Jiri Olsa" <jolsa@kernel.org>,
"Emil Tsalapatis" <emil@etsalapatis.com>,
"Ihor Solodrai" <ihor.solodrai@linux.dev>,
"Christophe Leroy (CS GROUP)" <chleroy@kernel.org>,
"Uwe Kleine-König" <u.kleine-koenig@baylibre.com>,
"Madhavan Srinivasan" <maddy@linux.ibm.com>,
"Michael Ellerman" <mpe@ellerman.id.au>,
"Nicholas Piggin" <npiggin@gmail.com>,
"Shivaprasad G Bhat" <sbhat@linux.ibm.com>,
"Thorsten Blum" <blum@kernel.org>,
"Alison Schofield" <alison.schofield@intel.com>,
"Dave Jiang" <dave.jiang@intel.com>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Guangshuo Li" <lgs201920130244@gmail.com>,
"Ira Weiny" <iweiny@kernel.org>,
"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
"Vishal Verma" <vishal.l.verma@intel.com>,
"Randy Dunlap" <rdunlap@infradead.org>,
"Shuah Khan" <skhan@linuxfoundation.org>,
linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
linux-security-module@vger.kernel.org,
linux-trace-kernel@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org, nvdimm@lists.linux.dev,
linux-doc@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: Re: [PATCH v4 05/11] seq_buf: Add seq_buf_strlen()
Date: Mon, 5 Oct 2026 04:22:15 -0700 [thread overview]
Message-ID: <20261005112209.1e47fa-kees@kernel.org> (raw)
In-Reply-To: <asIPlnb0noMd33rr@ashevche-desk.local>
On Sun, Oct 04, 2026 at 11:34:30AM +0300, Andy Shevchenko wrote:
> On Sun, Oct 04, 2026 at 12:26:39AM -0700, Kees Cook wrote:
> > I'd rather not make all 0-len strings return the .data segment's const
> > "" string...
>
> Good point. Perhaps then to add a short note to the kernel doc,
> so we won't see patches based on the suggestion like I gave?
Yeah, reasonable. :) For v5 I've added this to seq_buf_str()'s kernel-doc:
* A zero-sized seq_buf has nowhere to put a NUL, so the empty string
* is returned instead of writing to @s->buffer. Any other seq_buf
* returns @s->buffer, even when it holds an empty string, so callers
* always get their own buffer back.
-Kees
--
Kees Cook
next prev parent reply other threads:[~2026-10-05 11:22 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-03 3:59 [PATCH v4 00/11] seq_buf: Add seq_buf_strlen() Kees Cook
2026-10-03 3:59 ` [PATCH v4 01/11] seq_buf: Do not print an empty line from an overflowed seq_buf_do_printk() Kees Cook
2026-10-03 4:07 ` sashiko-bot
2026-10-03 4:50 ` bot+bpf-ci
2026-10-03 4:50 ` bot+bpf-ci
2026-10-05 10:05 ` Kees Cook
2026-10-03 3:59 ` [PATCH v4 02/11] seq_buf: Do not pop from an overflowed seq_buf Kees Cook
2026-10-03 4:05 ` sashiko-bot
2026-10-03 3:59 ` [PATCH v4 03/11] seq_buf: Copy what fits when seq_buf_puts() and seq_buf_putmem() overflow Kees Cook
2026-10-03 4:07 ` sashiko-bot
2026-10-03 4:50 ` bot+bpf-ci
2026-10-03 4:50 ` bot+bpf-ci
2026-10-05 10:06 ` Kees Cook
2026-10-03 3:59 ` [PATCH v4 04/11] seq_buf: Clear what a writer did not claim when a seq_buf overflows Kees Cook
2026-10-03 4:07 ` sashiko-bot
2026-10-03 4:50 ` bot+bpf-ci
2026-10-03 4:50 ` bot+bpf-ci
2026-10-03 3:59 ` [PATCH v4 05/11] seq_buf: Add seq_buf_strlen() Kees Cook
2026-10-03 4:04 ` sashiko-bot
2026-10-03 15:36 ` Andy Shevchenko
2026-10-04 7:26 ` Kees Cook
2026-10-04 8:34 ` Andy Shevchenko
2026-10-05 11:22 ` Kees Cook [this message]
2026-10-05 11:34 ` Alejandro Colomar
2026-10-05 15:58 ` Kees Cook
2026-10-05 16:43 ` Alejandro Colomar
2026-10-03 3:59 ` [PATCH v4 06/11] seq_buf: Add seq_buf_terminate() Kees Cook
2026-10-03 4:05 ` sashiko-bot
2026-10-03 3:59 ` [PATCH v4 07/11] bpf: Remove dead newline stripping from format_disasm_line() Kees Cook
2026-10-03 4:05 ` sashiko-bot
2026-10-03 3:59 ` [PATCH v4 08/11] seq_buf: Add seq_buf_init_append() Kees Cook
2026-10-03 4:05 ` sashiko-bot
2026-10-03 4:33 ` bot+bpf-ci
2026-10-03 4:33 ` bot+bpf-ci
2026-10-03 10:31 ` Kees Cook
2026-10-03 3:59 ` [PATCH v4 09/11] powerpc/papr_scm: Return the string length from the sysfs show functions Kees Cook
2026-10-03 4:06 ` sashiko-bot
2026-10-03 3:59 ` [PATCH v4 10/11] nvdimm: ndtest: Return the string length from flags_show() Kees Cook
2026-10-03 4:08 ` sashiko-bot
2026-10-03 3:59 ` [PATCH v4 11/11] docs: core-api: Document the seq_buf API Kees Cook
2026-10-03 4:03 ` sashiko-bot
2026-10-03 6:32 ` [PATCH v4 00/11] seq_buf: Add seq_buf_strlen() Alexei Starovoitov
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