Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932971AbaKRXje (ORCPT ); Tue, 18 Nov 2014 18:39:34 -0500 Received: from aserp1040.oracle.com ([141.146.126.69]:23912 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932115AbaKRXjb (ORCPT ); Tue, 18 Nov 2014 18:39:31 -0500 Message-ID: <546BD866.5050101@oracle.com> Date: Tue, 18 Nov 2014 18:38:14 -0500 From: Sasha Levin User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 MIME-Version: 1.0 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 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 X-Source-IP: acsinet21.oracle.com [141.146.126.237] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: 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 from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/