From: Marco Elver <elver@google.com> To: Andrey Konovalov <andreyknvl@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 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>, Jann Horn <jannh@google.com>, 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>, 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>, LKML <linux-kernel@vger.kernel.org>, kasan-dev <kasan-dev@googlegroups.com>, Linux ARM <linux-arm-kernel@lists.infradead.org>, Linux Memory Management List <linux-mm@kvack.org> Subject: Re: [PATCH v3 01/10] mm: add Kernel Electric-Fence infrastructure Date: Tue, 29 Sep 2020 15:11:35 +0200 [thread overview] Message-ID: <20200929131135.GA2822082@elver.google.com> (raw) In-Reply-To: <CAAeHK+zYP6xhAEcv75zdSt03V2wAOTed6vNBYReV_U7EsRmUBw@mail.gmail.com> On Tue, Sep 29, 2020 at 02:42PM +0200, Andrey Konovalov wrote: [...] > > + */ > > + index = (addr - (unsigned long)__kfence_pool) / (PAGE_SIZE * 2) - 1; > > Why do we subtract 1 here? We do have the metadata entry reserved for something? Above the declaration of __kfence_pool it says: * We allocate an even number of pages, as it simplifies calculations to map * address to metadata indices; effectively, the very first page serves as an * extended guard page, but otherwise has no special purpose. Hopefully that clarifies the `- 1` here. [...] > > + /* Allocation and free stack information. */ > > + int num_alloc_stack; > > + int num_free_stack; > > + unsigned long alloc_stack[KFENCE_STACK_DEPTH]; > > + unsigned long free_stack[KFENCE_STACK_DEPTH]; > > It was a concious decision to not use stackdepot, right? Perhaps it > makes sense to document the reason somewhere. Yes; we want to avoid the dynamic allocations that stackdepot does. [...] Thanks, -- Marco
WARNING: multiple messages have this Message-ID (diff)
From: Marco Elver <elver@google.com> To: Andrey Konovalov <andreyknvl@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 Memory Management List <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>, 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>, Jann Horn <jannh@google.com>, Borislav Petkov <bp@alien8.de>, Andy Lutomirski <luto@kernel.org>, 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>, LKML <linux-kernel@vger.kernel.org>, Pekka Enberg <penberg@kernel.org>, Joonsoo Kim <iamjoonsoo.kim@lge.com> Subject: Re: [PATCH v3 01/10] mm: add Kernel Electric-Fence infrastructure Date: Tue, 29 Sep 2020 15:11:35 +0200 [thread overview] Message-ID: <20200929131135.GA2822082@elver.google.com> (raw) In-Reply-To: <CAAeHK+zYP6xhAEcv75zdSt03V2wAOTed6vNBYReV_U7EsRmUBw@mail.gmail.com> On Tue, Sep 29, 2020 at 02:42PM +0200, Andrey Konovalov wrote: [...] > > + */ > > + index = (addr - (unsigned long)__kfence_pool) / (PAGE_SIZE * 2) - 1; > > Why do we subtract 1 here? We do have the metadata entry reserved for something? Above the declaration of __kfence_pool it says: * We allocate an even number of pages, as it simplifies calculations to map * address to metadata indices; effectively, the very first page serves as an * extended guard page, but otherwise has no special purpose. Hopefully that clarifies the `- 1` here. [...] > > + /* Allocation and free stack information. */ > > + int num_alloc_stack; > > + int num_free_stack; > > + unsigned long alloc_stack[KFENCE_STACK_DEPTH]; > > + unsigned long free_stack[KFENCE_STACK_DEPTH]; > > It was a concious decision to not use stackdepot, right? Perhaps it > makes sense to document the reason somewhere. Yes; we want to avoid the dynamic allocations that stackdepot does. [...] 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:[~2020-09-29 13:11 UTC|newest] Thread overview: 135+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-09-21 13:26 [PATCH v3 00/10] KFENCE: A low-overhead sampling-based memory safety error detector Marco Elver 2020-09-21 13:26 ` Marco Elver 2020-09-21 13:26 ` Marco Elver 2020-09-21 13:26 ` [PATCH v3 01/10] mm: add Kernel Electric-Fence infrastructure Marco Elver 2020-09-21 13:26 ` Marco Elver 2020-09-21 13:26 ` Marco Elver 2020-09-25 11:23 ` SeongJae Park 2020-09-25 11:23 ` SeongJae Park 2020-09-25 11:31 ` Marco Elver 2020-09-25 11:31 ` Marco Elver 2020-09-25 11:31 ` Marco Elver 2020-09-29 12:42 ` Andrey Konovalov 2020-09-29 12:42 ` Andrey Konovalov 2020-09-29 12:42 ` Andrey Konovalov 2020-09-29 13:11 ` Marco Elver [this message] 2020-09-29 13:11 ` Marco Elver 2020-09-29 13:48 ` Andrey Konovalov 2020-09-29 13:48 ` Andrey Konovalov 2020-09-29 13:48 ` Andrey Konovalov 2020-09-29 13:49 ` Marco Elver 2020-09-29 13:49 ` Marco Elver 2020-09-29 13:49 ` Marco Elver 2020-09-29 14:01 ` Andrey Konovalov 2020-09-29 14:01 ` Andrey Konovalov 2020-09-29 14:01 ` Andrey Konovalov 2020-09-29 14:24 ` Mark Rutland 2020-09-29 14:24 ` Mark Rutland 2020-09-29 14:51 ` Marco Elver 2020-09-29 14:51 ` Marco Elver 2020-09-29 14:51 ` Marco Elver 2020-09-29 15:05 ` Mark Rutland 2020-09-29 15:05 ` Mark Rutland 2020-10-05 16:00 ` Alexander Potapenko 2020-10-05 16:00 ` Alexander Potapenko 2020-10-05 16:00 ` Alexander Potapenko 2020-10-05 16:49 ` Jann Horn 2020-10-05 16:49 ` Jann Horn 2020-10-05 16:49 ` Jann Horn 2020-09-29 15:51 ` Alexander Potapenko 2020-09-29 15:51 ` Alexander Potapenko 2020-09-29 15:51 ` Alexander Potapenko 2020-10-01 18:11 ` Mark Rutland 2020-10-01 18:11 ` Mark Rutland 2020-09-21 13:26 ` [PATCH v3 02/10] x86, kfence: enable KFENCE for x86 Marco Elver 2020-09-21 13:26 ` Marco Elver 2020-09-21 13:26 ` Marco Elver 2020-09-21 13:26 ` [PATCH v3 03/10] arm64, kfence: enable KFENCE for ARM64 Marco Elver 2020-09-21 13:26 ` Marco Elver 2020-09-21 13:26 ` Marco Elver 2020-09-21 14:31 ` Will Deacon 2020-09-21 14:31 ` Will Deacon 2020-09-21 14:58 ` Alexander Potapenko 2020-09-21 14:58 ` Alexander Potapenko 2020-09-21 14:58 ` Alexander Potapenko 2020-09-21 15:37 ` Alexander Potapenko 2020-09-21 15:37 ` Alexander Potapenko 2020-09-21 15:37 ` Alexander Potapenko 2020-09-21 17:43 ` Will Deacon 2020-09-21 17:43 ` Will Deacon 2020-09-22 9:56 ` Marco Elver 2020-09-22 9:56 ` Marco Elver 2020-09-22 9:56 ` Marco Elver 2020-09-29 13:53 ` Mark Rutland 2020-09-29 13:53 ` Mark Rutland 2020-09-29 16:52 ` Alexander Potapenko 2020-09-29 16:52 ` Alexander Potapenko 2020-09-29 16:52 ` Alexander Potapenko 2020-09-25 15:25 ` Alexander Potapenko 2020-09-25 15:25 ` Alexander Potapenko 2020-09-25 15:25 ` Alexander Potapenko 2020-09-29 14:02 ` Mark Rutland 2020-09-29 14:02 ` Mark Rutland 2020-10-01 11:24 ` Alexander Potapenko 2020-10-01 11:24 ` Alexander Potapenko 2020-10-01 11:24 ` Alexander Potapenko 2020-10-01 17:57 ` Mark Rutland 2020-10-01 17:57 ` Mark Rutland 2020-10-08 9:40 ` Marco Elver 2020-10-08 9:40 ` Marco Elver 2020-10-08 9:40 ` Marco Elver 2020-10-08 10:45 ` Mark Rutland 2020-10-08 10:45 ` Mark Rutland 2020-10-14 19:12 ` Marco Elver 2020-10-14 19:12 ` Marco Elver 2020-10-14 19:12 ` Marco Elver 2020-10-15 13:39 ` Mark Rutland 2020-10-15 13:39 ` Mark Rutland 2020-10-15 14:15 ` Marco Elver 2020-10-15 14:15 ` Marco Elver 2020-10-15 14:15 ` Marco Elver 2020-09-28 11:53 ` Marco Elver 2020-09-28 11:53 ` Marco Elver 2020-09-28 11:53 ` Marco Elver 2020-09-29 14:27 ` Mark Rutland 2020-09-29 14:27 ` Mark Rutland 2020-09-29 17:04 ` Alexander Potapenko 2020-09-29 17:04 ` Alexander Potapenko 2020-09-29 17:04 ` Alexander Potapenko 2020-09-21 13:26 ` [PATCH v3 04/10] mm, kfence: insert KFENCE hooks for SLAB Marco Elver 2020-09-21 13:26 ` Marco Elver 2020-09-21 13:26 ` Marco Elver 2020-09-21 13:26 ` [PATCH v3 05/10] mm, kfence: insert KFENCE hooks for SLUB Marco Elver 2020-09-21 13:26 ` Marco Elver 2020-09-21 13:26 ` Marco Elver 2020-09-21 13:26 ` [PATCH v3 06/10] kfence, kasan: make KFENCE compatible with KASAN Marco Elver 2020-09-21 13:26 ` Marco Elver 2020-09-21 13:26 ` Marco Elver 2020-09-29 12:20 ` Andrey Konovalov 2020-09-29 12:20 ` Andrey Konovalov 2020-09-29 12:20 ` Andrey Konovalov 2020-09-29 13:13 ` Alexander Potapenko 2020-09-29 13:13 ` Alexander Potapenko 2020-09-29 13:13 ` Alexander Potapenko 2020-09-21 13:26 ` [PATCH v3 07/10] kfence, kmemleak: make KFENCE compatible with KMEMLEAK Marco Elver 2020-09-21 13:26 ` Marco Elver 2020-09-21 13:26 ` Marco Elver 2020-09-21 13:26 ` [PATCH v3 08/10] kfence, lockdep: make KFENCE compatible with lockdep Marco Elver 2020-09-21 13:26 ` Marco Elver 2020-09-21 13:26 ` Marco Elver 2020-09-21 13:26 ` [PATCH v3 09/10] kfence, Documentation: add KFENCE documentation Marco Elver 2020-09-21 13:26 ` Marco Elver 2020-09-21 13:26 ` Marco Elver 2020-09-21 13:26 ` [PATCH v3 10/10] kfence: add test suite Marco Elver 2020-09-21 13:26 ` Marco Elver 2020-09-21 13:26 ` Marco Elver 2020-09-21 17:13 ` Paul E. McKenney 2020-09-21 17:13 ` Paul E. McKenney 2020-09-21 17:37 ` Marco Elver 2020-09-21 17:37 ` Marco Elver 2020-09-21 17:37 ` Marco Elver 2020-09-21 17:48 ` Paul E. McKenney 2020-09-21 17:48 ` Paul E. McKenney 2020-09-21 13:38 ` [PATCH v3 00/10] KFENCE: A low-overhead sampling-based memory safety error detector Dmitry Vyukov 2020-09-21 13:38 ` Dmitry Vyukov 2020-09-21 13:38 ` Dmitry Vyukov
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