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t=1726093125; bh=+6cSwg/X+10bSLWe5d2NRG2QHpKGwxHJCNr4zPB6bv0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=aB3Ma8tTz5vz736fDP2NRhsK/Krhq65bIP1s3XKcy/ZS2XrRJkCXJSvScSICyZizS muZy8dHDlOoJcut6QFbUEcLvIAhBUGZzOWdfN/Er19/ztR7mZTI3D1DI9Fm2hpuzCV WmMhZhImMWkLdp8cVGqV44FcSVvarYZ05TLA7q1rDTZ+ZCMRTd8mSjgamQSRNl8APm S6DlgGDQ6xF+kerYWM6O1lE4fZ/ru5lUBwr85S3GLJJGL4J4WFusfnhABorwb6tmY1 o1kJKdxZBY/rS7OUOKLWsvQUo58EuJaKPsliABRdDAC2Y168a0oRry2qSD1X3/UlYb AIZ7RyMJo2pgw== Date: Wed, 11 Sep 2024 15:18:44 -0700 From: Kees Cook To: Suren Baghdasaryan Cc: Vlastimil Babka , Kent Overstreet , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, linux-mm@kvack.org, "GONG, Ruiqi" , Jann Horn , Matteo Rizzo , jvoisin , Xiu Jianfeng , linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: Re: [PATCH 3/5] codetag: Introduce codetag_early_walk() Message-ID: <202409111518.FFAD85919@keescook> References: <20240809072532.work.266-kees@kernel.org> <20240809073309.2134488-3-kees@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Stat-Signature: 7r3a8nbmttyesci5f5tpbe4byjb88hhr X-Rspamd-Queue-Id: 43AAD180006 X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1726093126-679218 X-HE-Meta: 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 09+kZxhP 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Aug 29, 2024 at 08:39:29AM -0700, Suren Baghdasaryan wrote: > On Fri, Aug 9, 2024 at 12:33 AM Kees Cook wrote: > > > > In order to process builtin alloc_tags much earlier during boot (before > > register_codetag() is processed), provide codetag_early_walk() that > > perform a lockless walk with a specified callback function. This will be > > used to allocate required caches that cannot be allocated on demand. > > > > Signed-off-by: Kees Cook > > --- > > Cc: Suren Baghdasaryan > > Cc: Kent Overstreet > > Cc: Vlastimil Babka > > Cc: Christoph Lameter > > Cc: Pekka Enberg > > Cc: David Rientjes > > Cc: Joonsoo Kim > > Cc: Andrew Morton > > Cc: Roman Gushchin > > Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> > > Cc: linux-mm@kvack.org > > --- > > include/linux/codetag.h | 2 ++ > > lib/codetag.c | 16 ++++++++++++++++ > > 2 files changed, 18 insertions(+) > > > > diff --git a/include/linux/codetag.h b/include/linux/codetag.h > > index c2a579ccd455..9eb1fcd90570 100644 > > --- a/include/linux/codetag.h > > +++ b/include/linux/codetag.h > > @@ -64,6 +64,8 @@ void codetag_lock_module_list(struct codetag_type *cttype, bool lock); > > bool codetag_trylock_module_list(struct codetag_type *cttype); > > struct codetag_iterator codetag_get_ct_iter(struct codetag_type *cttype); > > struct codetag *codetag_next_ct(struct codetag_iterator *iter); > > +void codetag_early_walk(const struct codetag_type_desc *desc, > > + void (*callback)(struct codetag *ct)); > > > > void codetag_to_text(struct seq_buf *out, struct codetag *ct); > > > > diff --git a/lib/codetag.c b/lib/codetag.c > > index ef7634c7ee18..9d563c8c088a 100644 > > --- a/lib/codetag.c > > +++ b/lib/codetag.c > > @@ -154,6 +154,22 @@ static struct codetag_range get_section_range(struct module *mod, > > }; > > } > > > > +void codetag_early_walk(const struct codetag_type_desc *desc, > > + void (*callback)(struct codetag *ct)) > > +{ > > + struct codetag_range range; > > + struct codetag *ct; > > + > > + range = get_section_range(NULL, desc->section); > > + if (!range.start || !range.stop || > > + range.start == range.stop || > > + range.start > range.stop) > > + return; > > I think this check can be simplified to: > > if (!range.start || range.start >= range.stop) > return; > > nit: Technically (!range.start) should also never trigger. In a valid > image these symbols are either missing (range.start == range.stop == > NULL) or both are defined and (range.start < range.stop). Yeah, all true. I was mainly copying all the checks that existed in the "slow path" version. I will adjust this for the next version. -- Kees Cook