From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f41.google.com (mail-oi0-f41.google.com [209.85.218.41]) by kanga.kvack.org (Postfix) with ESMTP id 6F0F36B0038 for ; Tue, 18 Nov 2014 18:39:09 -0500 (EST) Received: by mail-oi0-f41.google.com with SMTP id a3so6684968oib.14 for ; Tue, 18 Nov 2014 15:39:09 -0800 (PST) Received: from aserp1040.oracle.com (aserp1040.oracle.com. [141.146.126.69]) by mx.google.com with ESMTPS id 9si767089oic.48.2014.11.18.15.39.08 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Tue, 18 Nov 2014 15:39:08 -0800 (PST) Message-ID: <546BD866.5050101@oracle.com> Date: Tue, 18 Nov 2014 18:38:14 -0500 From: Sasha Levin MIME-Version: 1.0 Subject: Re: [PATCH v6 00/11] Kernel address sanitizer - runtime memory debugger. References: <1404905415-9046-1-git-send-email-a.ryabinin@samsung.com> <1415199241-5121-1-git-send-email-a.ryabinin@samsung.com> In-Reply-To: <1415199241-5121-1-git-send-email-a.ryabinin@samsung.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrey Ryabinin , akpm@linux-foundation.org Cc: Dmitry Vyukov , Konstantin Serebryany , Dmitry Chernenkov , Andrey Konovalov , Yuri Gribov , Konstantin Khlebnikov , Michal Marek , Thomas Gleixner , Ingo Molnar , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Dave Hansen , Andi Kleen , Vegard Nossum , "H. Peter Anvin" , x86@kernel.org, linux-mm@kvack.org, Randy Dunlap , Peter Zijlstra , Alexander Viro , Dave Jones , Jonathan Corbet , Joe Perches , linux-kernel@vger.kernel.org Hi Andrey, After the recent exchange of mails about kasan it came to me that I haven't seen a kasan warning for a while now. To give kasan a quick test I added a rather simple error which should generate a kasan warning about accessing userspace memory (yes, I know kasan has a test module but my setup doesn't like modules): diff --git a/net/socket.c b/net/socket.c index fe20c31..794e9f4 100644 --- a/net/socket.c +++ b/net/socket.c @@ -1902,7 +1902,7 @@ SYSCALL_DEFINE5(setsockopt, int, fd, int, level, int, optname, { int err, fput_needed; struct socket *sock; - + *((char *)10) = 5; if (optlen < 0) return -EINVAL; A gfp was triggered, but no kasan warning was shown. I remembered that one of the biggest changes in kasan was the introduction of inline instrumentation, so I went ahead to disable it and see if it helps. But the only result of that was having the boot process hang pretty early: [...] [ 0.000000] IOAPIC[0]: apic_id 21, version 17, address 0xfec00000, GSI 0-23 [ 0.000000] Processors: 20 [ 0.000000] smpboot: Allowing 24 CPUs, 4 hotplug CPUs [ 0.000000] e820: [mem 0xd0000000-0xffffffff] available for PCI devices [ 0.000000] Booting paravirtualized kernel on KVM [ 0.000000] setup_percpu: NR_CPUS:8192 nr_cpumask_bits:24 nr_cpu_ids:24 nr_node_ids:1 [ 0.000000] PERCPU: Embedded 491 pages/cpu @ffff8808dce00000 s1971864 r8192 d31080 u2097152 *HANG* I'm using the latest gcc: $ gcc --version gcc (GCC) 5.0.0 20141117 (experimental) I'll continue looking into it tomorrow, just hoping it rings a bell... Thanks, Sasha -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org