From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934304AbeAJJ7D (ORCPT + 1 other); Wed, 10 Jan 2018 04:59:03 -0500 Received: from mx2.suse.de ([195.135.220.15]:50295 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934265AbeAJJ6s (ORCPT ); Wed, 10 Jan 2018 04:58:48 -0500 Date: Wed, 10 Jan 2018 10:58:43 +0100 Message-ID: From: Takashi Iwai To: "Eric Biggers" Cc: "syzbot" , , , , Subject: Re: KASAN: null-ptr-deref Write in linear_transfer In-Reply-To: <20180110080800.GE931@zzz.localdomain> References: <001a1147e1988b160a05620552eb@google.com> <20180110080800.GE931@zzz.localdomain> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/25.3 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: On Wed, 10 Jan 2018 09:08:00 +0100, Eric Biggers wrote: > > On Fri, Jan 05, 2018 at 02:58:02AM -0800, syzbot wrote: > > Hello, > > > > syzkaller hit the following crash on > > 30a7acd573899fd8b8ac39236eff6468b195ac7d > > git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/master > > compiler: gcc (GCC) 7.1.1 20170620 > > .config is attached > > Raw console output is attached. > > C reproducer is attached > > syzkaller reproducer is attached. See https://goo.gl/kgGztJ > > for information about syzkaller reproducers > > > > > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > > Reported-by: syzbot+a8f5641f452c7e6abf03@syzkaller.appspotmail.com > > It will help syzbot understand when the bug is fixed. See footer for > > details. > > If you forward the report, please keep this part and the footer. > > > > ================================================================== > > BUG: KASAN: null-ptr-deref in memcpy include/linux/string.h:344 [inline] > > BUG: KASAN: null-ptr-deref in do_convert sound/core/oss/linear.c:52 [inline] > > BUG: KASAN: null-ptr-deref in convert sound/core/oss/linear.c:81 [inline] > > BUG: KASAN: null-ptr-deref in linear_transfer+0x634/0x900 > > sound/core/oss/linear.c:110 > > Write of size 2 at addr (null) by task syzkaller360172/7860 > > > > CPU: 0 PID: 7860 Comm: syzkaller360172 Not tainted 4.15.0-rc6+ #155 > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > > Google 01/01/2011 > > Call Trace: > > __dump_stack lib/dump_stack.c:17 [inline] > > dump_stack+0x194/0x257 lib/dump_stack.c:53 > > kasan_report_error mm/kasan/report.c:349 [inline] > > kasan_report+0x13b/0x340 mm/kasan/report.c:409 > > check_memory_region_inline mm/kasan/kasan.c:260 [inline] > > check_memory_region+0x137/0x190 mm/kasan/kasan.c:267 > > memcpy+0x37/0x50 mm/kasan/kasan.c:303 > > memcpy include/linux/string.h:344 [inline] > > do_convert sound/core/oss/linear.c:52 [inline] > > convert sound/core/oss/linear.c:81 [inline] > > linear_transfer+0x634/0x900 sound/core/oss/linear.c:110 > > snd_pcm_plug_write_transfer+0x22d/0x420 sound/core/oss/pcm_plugin.c:611 > > snd_pcm_oss_write2+0x260/0x420 sound/core/oss/pcm_oss.c:1311 > > snd_pcm_oss_sync1+0x1cc/0x550 sound/core/oss/pcm_oss.c:1530 > > snd_pcm_oss_sync+0x5b6/0x830 sound/core/oss/pcm_oss.c:1604 > > snd_pcm_oss_release+0x20b/0x280 sound/core/oss/pcm_oss.c:2431 > > __fput+0x327/0x7e0 fs/file_table.c:210 > > ____fput+0x15/0x20 fs/file_table.c:244 > > task_work_run+0x199/0x270 kernel/task_work.c:113 > > exit_task_work include/linux/task_work.h:22 [inline] > > do_exit+0x9bb/0x1ad0 kernel/exit.c:865 > > do_group_exit+0x149/0x400 kernel/exit.c:968 > > get_signal+0x73f/0x16c0 kernel/signal.c:2335 > > do_signal+0x90/0x1eb0 arch/x86/kernel/signal.c:809 > > exit_to_usermode_loop+0x214/0x310 arch/x86/entry/common.c:158 > > prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline] > > syscall_return_slowpath arch/x86/entry/common.c:264 [inline] > > do_syscall_32_irqs_on arch/x86/entry/common.c:333 [inline] > > do_fast_syscall_32+0xbfd/0xf9d arch/x86/entry/common.c:389 > > entry_SYSENTER_compat+0x54/0x63 arch/x86/entry/entry_64_compat.S:129 > > Still reproducible even after all the fixes currently in sound/for-linus. Interesting, I can't reproduce it on my VM any longer... Takashi