From: Marco Elver <elver@google.com> To: Jann Horn <jannh@google.com> Cc: Andrew Morton <akpm@linux-foundation.org>, Alexander Potapenko <glider@google.com>, "H . Peter Anvin" <hpa@zytor.com>, "Paul E . McKenney" <paulmck@kernel.org>, Andrey Konovalov <andreyknvl@google.com>, Andrey Ryabinin <aryabinin@virtuozzo.com>, Andy Lutomirski <luto@kernel.org>, Borislav Petkov <bp@alien8.de>, Catalin Marinas <catalin.marinas@arm.com>, Christoph Lameter <cl@linux.com>, Dave Hansen <dave.hansen@linux.intel.com>, David Rientjes <rientjes@google.com>, Dmitry Vyukov <dvyukov@google.com>, Eric Dumazet <edumazet@google.com>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Hillf Danton <hdanton@sina.com>, Ingo Molnar <mingo@redhat.com>, Jonathan Cameron <Jonathan.Cameron@huawei.com>, Jonathan Corbet <corbet@lwn.net>, Joonsoo Kim <iamjoonsoo.kim@lge.com>, Kees Cook <keescook@chromium.org>, Mark Rutland <mark.rutland@arm.com>, Pekka Enberg <penberg@kernel.org>, Peter Zijlstra <peterz@infradead.org>, SeongJae Park <sjpark@amazon.com>, Thomas Gleixner <tglx@linutronix.de>, Vlastimil Babka <vbabka@suse.cz>, Will Deacon <will@kernel.org>, "the arch/x86 maintainers" <x86@kernel.org>, "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>, kernel list <linux-kernel@vger.kernel.org>, kasan-dev <kasan-dev@googlegroups.com>, Linux ARM <linux-arm-kernel@lists.infradead.org>, Linux-MM <linux-mm@kvack.org> Subject: Re: [PATCH v4 03/11] arm64, kfence: enable KFENCE for ARM64 Date: Fri, 2 Oct 2020 16:18:48 +0200 [thread overview] Message-ID: <CANpmjNMcdM2MSL5J6ewChovxZbe-rKncU4LekQiXwKoVY0xDnQ@mail.gmail.com> (raw) In-Reply-To: <CAG48ez1VNQo2HZSDDxUqtM4w63MmQsDc4SH0xLw92E6vXaPWrg@mail.gmail.com> On Fri, 2 Oct 2020 at 08:48, Jann Horn <jannh@google.com> wrote: > > On Tue, Sep 29, 2020 at 3:38 PM Marco Elver <elver@google.com> wrote: > > Add architecture specific implementation details for KFENCE and enable > > KFENCE for the arm64 architecture. In particular, this implements the > > required interface in <asm/kfence.h>. Currently, the arm64 version does > > not yet use a statically allocated memory pool, at the cost of a pointer > > load for each is_kfence_address(). > [...] > > diff --git a/arch/arm64/include/asm/kfence.h b/arch/arm64/include/asm/kfence.h > [...] > > +static inline bool arch_kfence_initialize_pool(void) > > +{ > > + const unsigned int num_pages = ilog2(roundup_pow_of_two(KFENCE_POOL_SIZE / PAGE_SIZE)); > > + struct page *pages = alloc_pages(GFP_KERNEL, num_pages); > > + > > + if (!pages) > > + return false; > > + > > + __kfence_pool = page_address(pages); > > + return true; > > +} > > If you're going to do "virt_to_page(meta->addr)->slab_cache = cache;" > on these pages in kfence_guarded_alloc(), and pass them into kfree(), > you'd better mark these pages as non-compound - something like > alloc_pages_exact() or split_page() may help. Otherwise, I think when > SLUB's kfree() does virt_to_head_page() right at the start, that will > return a pointer to the first page of the entire __kfence_pool, and > then when it loads page->slab_cache, it gets some random cache and > stuff blows up. Kinda surprising that you haven't run into that during > your testing, maybe I'm missing something... I added a WARN_ON() check in kfence_initialize_pool() to check if our pages are compound or not; they are not. In slub.c, __GFP_COMP is passed to alloc_pages(), which causes them to have a compound head I believe. > Also, this kinda feels like it should be the "generic" version of > arch_kfence_initialize_pool() and live in mm/kfence/core.c ? Done for v5. Thanks, -- Marco
WARNING: multiple messages have this Message-ID (diff)
From: Marco Elver <elver@google.com> To: Jann Horn <jannh@google.com> Cc: Mark Rutland <mark.rutland@arm.com>, Hillf Danton <hdanton@sina.com>, "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>, Peter Zijlstra <peterz@infradead.org>, Catalin Marinas <catalin.marinas@arm.com>, Dave Hansen <dave.hansen@linux.intel.com>, Linux-MM <linux-mm@kvack.org>, Eric Dumazet <edumazet@google.com>, Alexander Potapenko <glider@google.com>, "H . Peter Anvin" <hpa@zytor.com>, Christoph Lameter <cl@linux.com>, Will Deacon <will@kernel.org>, SeongJae Park <sjpark@amazon.com>, Jonathan Corbet <corbet@lwn.net>, the arch/x86 maintainers <x86@kernel.org>, kasan-dev <kasan-dev@googlegroups.com>, Ingo Molnar <mingo@redhat.com>, Vlastimil Babka <vbabka@suse.cz>, David Rientjes <rientjes@google.com>, Andrey Ryabinin <aryabinin@virtuozzo.com>, Kees Cook <keescook@chromium.org>, "Paul E . McKenney" <paulmck@kernel.org>, Andrey Konovalov <andreyknvl@google.com>, Borislav Petkov <bp@alien8.de>, Andy Lutomirski <luto@kernel.org>, Jonathan Cameron <Jonathan.Cameron@huawei.com>, Thomas Gleixner <tglx@linutronix.de>, Andrew Morton <akpm@linux-foundation.org>, Dmitry Vyukov <dvyukov@google.com>, Linux ARM <linux-arm-kernel@lists.infradead.org>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, kernel list <linux-kernel@vger.kernel.org>, Pekka Enberg <penberg@kernel.org>, Joonsoo Kim <iamjoonsoo.kim@lge.com> Subject: Re: [PATCH v4 03/11] arm64, kfence: enable KFENCE for ARM64 Date: Fri, 2 Oct 2020 16:18:48 +0200 [thread overview] Message-ID: <CANpmjNMcdM2MSL5J6ewChovxZbe-rKncU4LekQiXwKoVY0xDnQ@mail.gmail.com> (raw) In-Reply-To: <CAG48ez1VNQo2HZSDDxUqtM4w63MmQsDc4SH0xLw92E6vXaPWrg@mail.gmail.com> On Fri, 2 Oct 2020 at 08:48, Jann Horn <jannh@google.com> wrote: > > On Tue, Sep 29, 2020 at 3:38 PM Marco Elver <elver@google.com> wrote: > > Add architecture specific implementation details for KFENCE and enable > > KFENCE for the arm64 architecture. In particular, this implements the > > required interface in <asm/kfence.h>. Currently, the arm64 version does > > not yet use a statically allocated memory pool, at the cost of a pointer > > load for each is_kfence_address(). > [...] > > diff --git a/arch/arm64/include/asm/kfence.h b/arch/arm64/include/asm/kfence.h > [...] > > +static inline bool arch_kfence_initialize_pool(void) > > +{ > > + const unsigned int num_pages = ilog2(roundup_pow_of_two(KFENCE_POOL_SIZE / PAGE_SIZE)); > > + struct page *pages = alloc_pages(GFP_KERNEL, num_pages); > > + > > + if (!pages) > > + return false; > > + > > + __kfence_pool = page_address(pages); > > + return true; > > +} > > If you're going to do "virt_to_page(meta->addr)->slab_cache = cache;" > on these pages in kfence_guarded_alloc(), and pass them into kfree(), > you'd better mark these pages as non-compound - something like > alloc_pages_exact() or split_page() may help. Otherwise, I think when > SLUB's kfree() does virt_to_head_page() right at the start, that will > return a pointer to the first page of the entire __kfence_pool, and > then when it loads page->slab_cache, it gets some random cache and > stuff blows up. Kinda surprising that you haven't run into that during > your testing, maybe I'm missing something... I added a WARN_ON() check in kfence_initialize_pool() to check if our pages are compound or not; they are not. In slub.c, __GFP_COMP is passed to alloc_pages(), which causes them to have a compound head I believe. > Also, this kinda feels like it should be the "generic" version of > arch_kfence_initialize_pool() and live in mm/kfence/core.c ? Done for v5. Thanks, -- Marco _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-10-02 14:19 UTC|newest] Thread overview: 103+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-09-29 13:38 [PATCH v4 00/11] KFENCE: A low-overhead sampling-based memory safety error detector Marco Elver 2020-09-29 13:38 ` Marco Elver 2020-09-29 13:38 ` Marco Elver 2020-09-29 13:38 ` [PATCH v4 01/11] mm: add Kernel Electric-Fence infrastructure Marco Elver 2020-09-29 13:38 ` Marco Elver 2020-09-29 13:38 ` Marco Elver 2020-10-02 6:33 ` Jann Horn 2020-10-02 6:33 ` Jann Horn 2020-10-02 6:33 ` Jann Horn 2020-10-02 7:53 ` Jann Horn 2020-10-02 7:53 ` Jann Horn 2020-10-02 7:53 ` Jann Horn 2020-10-02 14:22 ` Dmitry Vyukov 2020-10-02 14:22 ` Dmitry Vyukov 2020-10-02 14:22 ` Dmitry Vyukov 2020-10-02 15:06 ` Mark Rutland 2020-10-02 15:06 ` Mark Rutland 2020-10-02 18:27 ` Jann Horn 2020-10-02 18:27 ` Jann Horn 2020-10-02 18:27 ` Jann Horn 2020-10-05 18:59 ` Marco Elver 2020-10-05 18:59 ` Marco Elver 2020-10-05 18:59 ` Marco Elver 2020-10-02 17:19 ` Marco Elver 2020-10-02 17:19 ` Marco Elver 2020-10-02 19:31 ` Jann Horn 2020-10-02 19:31 ` Jann Horn 2020-10-02 19:31 ` Jann Horn 2020-10-02 21:12 ` Marco Elver 2020-10-02 21:12 ` Marco Elver 2020-10-02 21:28 ` Marco Elver 2020-10-02 21:28 ` Marco Elver 2020-10-02 21:28 ` Marco Elver 2020-10-02 22:27 ` Jann Horn 2020-10-02 22:27 ` Jann Horn 2020-10-02 22:27 ` Jann Horn 2020-10-12 14:20 ` Marco Elver 2020-10-12 14:20 ` Marco Elver 2020-10-12 14:20 ` Marco Elver 2020-09-29 13:38 ` [PATCH v4 02/11] x86, kfence: enable KFENCE for x86 Marco Elver 2020-09-29 13:38 ` Marco Elver 2020-09-29 13:38 ` Marco Elver 2020-10-02 5:45 ` Jann Horn 2020-10-02 5:45 ` Jann Horn 2020-10-02 5:45 ` Jann Horn 2020-10-07 13:08 ` Marco Elver 2020-10-07 13:08 ` Marco Elver 2020-10-07 13:08 ` Marco Elver 2020-10-07 14:14 ` Jann Horn 2020-10-07 14:14 ` Jann Horn 2020-10-07 14:14 ` Jann Horn 2020-10-07 14:41 ` Marco Elver 2020-10-07 14:41 ` Marco Elver 2020-10-07 14:41 ` Marco Elver 2020-10-09 17:40 ` Marco Elver 2020-10-09 17:40 ` Marco Elver 2020-10-02 6:08 ` Jann Horn 2020-10-02 6:08 ` Jann Horn 2020-10-02 6:08 ` Jann Horn 2020-09-29 13:38 ` [PATCH v4 03/11] arm64, kfence: enable KFENCE for ARM64 Marco Elver 2020-09-29 13:38 ` Marco Elver 2020-09-29 13:38 ` Marco Elver 2020-10-02 6:47 ` Jann Horn 2020-10-02 6:47 ` Jann Horn 2020-10-02 6:47 ` Jann Horn 2020-10-02 14:18 ` Marco Elver [this message] 2020-10-02 14:18 ` Marco Elver 2020-10-02 14:18 ` Marco Elver 2020-10-02 16:10 ` Jann Horn 2020-10-02 16:10 ` Jann Horn 2020-10-02 16:10 ` Jann Horn 2020-09-29 13:38 ` [PATCH v4 04/11] mm, kfence: insert KFENCE hooks for SLAB Marco Elver 2020-09-29 13:38 ` Marco Elver 2020-09-29 13:38 ` Marco Elver 2020-09-29 13:38 ` [PATCH v4 05/11] mm, kfence: insert KFENCE hooks for SLUB Marco Elver 2020-09-29 13:38 ` Marco Elver 2020-09-29 13:38 ` Marco Elver 2020-10-02 7:07 ` Jann Horn 2020-10-02 7:07 ` Jann Horn 2020-10-02 7:07 ` Jann Horn 2020-10-05 9:29 ` Alexander Potapenko 2020-10-05 9:29 ` Alexander Potapenko 2020-10-05 9:29 ` Alexander Potapenko 2020-09-29 13:38 ` [PATCH v4 06/11] kfence, kasan: make KFENCE compatible with KASAN Marco Elver 2020-09-29 13:38 ` Marco Elver 2020-09-29 13:38 ` Marco Elver 2020-09-29 13:38 ` [PATCH v4 07/11] kfence, kmemleak: make KFENCE compatible with KMEMLEAK Marco Elver 2020-09-29 13:38 ` Marco Elver 2020-09-29 13:38 ` Marco Elver 2020-09-29 13:38 ` [PATCH v4 08/11] kfence, lockdep: make KFENCE compatible with lockdep Marco Elver 2020-09-29 13:38 ` Marco Elver 2020-09-29 13:38 ` Marco Elver 2020-09-29 13:38 ` [PATCH v4 09/11] kfence, Documentation: add KFENCE documentation Marco Elver 2020-09-29 13:38 ` Marco Elver 2020-09-29 13:38 ` Marco Elver 2020-09-29 13:38 ` [PATCH v4 10/11] kfence: add test suite Marco Elver 2020-09-29 13:38 ` Marco Elver 2020-09-29 13:38 ` Marco Elver 2020-09-29 13:38 ` [PATCH v4 11/11] MAINTAINERS: Add entry for KFENCE Marco Elver 2020-09-29 13:38 ` Marco Elver 2020-09-29 13:38 ` Marco Elver 2020-09-29 14:21 ` SeongJae Park 2020-09-29 14:21 ` SeongJae Park
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