From: Andrey Konovalov <andreyknvl@google.com>
To: Kees Cook <keescook@chromium.org>,
Alexander Potapenko <glider@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Elena Reshetova <elena.reshetova@intel.com>,
"the arch/x86 maintainers" <x86@kernel.org>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Popov <alex.popov@linux.com>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Jann Horn <jannh@google.com>,
kernel-hardening@lists.openwall.com,
linux-hardening@vger.kernel.org,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Linux Memory Management List <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Vlastimil Babka <vbabka@suse.cz>,
David Hildenbrand <david@redhat.com>,
Mike Rapoport <rppt@linux.ibm.com>,
Andrew Morton <akpm@linux-foundation.org>,
Jonathan Corbet <corbet@lwn.net>,
Randy Dunlap <rdunlap@infradead.org>
Subject: Re: [PATCH v5 3/7] init_on_alloc: Unpessimize default-on builds
Date: Wed, 10 Mar 2021 13:52:04 +0100 [thread overview]
Message-ID: <CAAeHK+xog8-DP1o=1qqKgSP7Hii2Yjah6oyowNE3zSNVW5pRSw@mail.gmail.com> (raw)
In-Reply-To: <20210309214301.678739-4-keescook@chromium.org>
On Tue, Mar 9, 2021 at 10:43 PM Kees Cook <keescook@chromium.org> wrote:
>
> Right now, the state of CONFIG_INIT_ON_ALLOC_DEFAULT_ON (and
> ...ON_FREE...) did not change the assembly ordering of the static branch
> tests. Use the new jump_label macro to check CONFIG settings to default
> to the "expected" state, unpessimizes the resulting assembly code.
>
> Reviewed-by: Alexander Potapenko <glider@google.com>
> Link: https://lore.kernel.org/lkml/CAG_fn=X0DVwqLaHJTO6Jw7TGcMSm77GKHinrd0m_6y0SzWOrFA@mail.gmail.com/
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
> include/linux/mm.h | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index bf341a9bfe46..2ccd856ac0d1 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -2874,7 +2874,8 @@ static inline void kernel_unpoison_pages(struct page *page, int numpages) { }
> DECLARE_STATIC_KEY_MAYBE(CONFIG_INIT_ON_ALLOC_DEFAULT_ON, init_on_alloc);
> static inline bool want_init_on_alloc(gfp_t flags)
> {
> - if (static_branch_unlikely(&init_on_alloc))
> + if (static_branch_maybe(CONFIG_INIT_ON_ALLOC_DEFAULT_ON,
> + &init_on_alloc))
> return true;
> return flags & __GFP_ZERO;
> }
> @@ -2882,7 +2883,8 @@ static inline bool want_init_on_alloc(gfp_t flags)
> DECLARE_STATIC_KEY_MAYBE(CONFIG_INIT_ON_FREE_DEFAULT_ON, init_on_free);
> static inline bool want_init_on_free(void)
> {
> - return static_branch_unlikely(&init_on_free);
> + return static_branch_maybe(CONFIG_INIT_ON_FREE_DEFAULT_ON,
> + &init_on_free);
> }
>
> extern bool _debug_pagealloc_enabled_early;
Should we also update slab_want_init_on_alloc() and slab_want_init_on_free()?
next prev parent reply other threads:[~2021-03-10 12:53 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-09 21:42 [PATCH v5 0/7] Optionally randomize kernel stack offset each syscall Kees Cook
2021-03-09 21:42 ` [PATCH v5 1/7] mm: Restore init_on_* static branch defaults Kees Cook
2021-03-10 23:56 ` Andrew Morton
2021-03-15 17:28 ` Kees Cook
2021-03-09 21:42 ` [PATCH v5 2/7] jump_label: Provide CONFIG-driven build state defaults Kees Cook
2021-03-09 21:42 ` [PATCH v5 3/7] init_on_alloc: Unpessimize default-on builds Kees Cook
2021-03-10 12:52 ` Andrey Konovalov [this message]
2021-03-10 21:03 ` Kees Cook
2021-03-09 21:42 ` [PATCH v5 4/7] stack: Optionally randomize kernel stack offset each syscall Kees Cook
2021-03-09 21:42 ` [PATCH v5 5/7] x86/entry: Enable random_kstack_offset support Kees Cook
2021-03-09 21:43 ` [PATCH v5 6/7] arm64: entry: " Kees Cook
2021-03-09 21:43 ` [PATCH v5 7/7] lkdtm: Add REPORT_STACK for checking stack offsets Kees Cook
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