From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED,USER_AGENT_MUTT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 353B4C4360F for ; Wed, 3 Apr 2019 15:19:52 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id EE0152075E for ; Wed, 3 Apr 2019 15:19:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="P1b8KNcY" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EE0152075E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=1JqSkdaUyRsjvL8bE7fbG6HwxzUdRwbNuSxzfNiMhAo=; b=P1b8KNcYkRChR3 UP76vderqIFxLuUeQHM/i2UiOD/fSC7ZEb8LP+mxJT1ScOBP/jnHteWTcQIs0pA41ocvwszqCoh2Q 5eknu5joB3JimDVf8sKNAE8jKdP/3y1Om7L+ffbedtuw83A0v44KzCnlKW4ioEPhy68qxez75W8vn 5NIevjv4Wr2UAwSmVdg7M1JmJDF1n/RN2YOrhcn5F+Oi2VAUyCPiz+6FKcxqSyRLIPEPFx5IZ2xzy SBmzFY8jW+zMBG93X7om0yIioGEW7nRHmvgL4Rjn4OuC3s+cyj7mDPgsL0D2qhX4OQYUD9GcCEA2I SCpVKaEp0+mCcEdxHRbA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hBhg4-0007Dw-Eo; Wed, 03 Apr 2019 15:19:48 +0000 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70] helo=foss.arm.com) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hBhg1-0007DM-Bv for linux-arm-kernel@lists.infradead.org; Wed, 03 Apr 2019 15:19:46 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 721BFA78; Wed, 3 Apr 2019 08:19:43 -0700 (PDT) Received: from fuggles.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B88453F68F; Wed, 3 Apr 2019 08:19:37 -0700 (PDT) Date: Wed, 3 Apr 2019 16:19:32 +0100 From: Will Deacon To: Jens Axboe Subject: Re: [PATCH 2/2] arch: add pidfd and io_uring syscalls everywhere Message-ID: <20190403151932.GA16866@fuggles.cambridge.arm.com> References: <20190325143521.34928-1-arnd@arndb.de> <20190325144737.703921-1-arnd@arndb.de> <87tvff24a1.fsf@concordia.ellerman.id.au> <20190403111134.GA7159@fuggles.cambridge.arm.com> <9d673dfd-0051-3676-653e-6376430d73dd@kernel.dk> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <9d673dfd-0051-3676-653e-6376430d73dd@kernel.dk> User-Agent: Mutt/1.11.1+86 (6f28e57d73f2) () X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190403_081945_414255_285D2C0D X-CRM114-Status: GOOD ( 14.60 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Rich Felker , linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org, Benjamin Herrenschmidt , Heiko Carstens , linux-mips@vger.kernel.org, "James E . J . Bottomley" , Max Filippov , Paul Mackerras , sparclinux@vger.kernel.org, linux-s390@vger.kernel.org, Michael Ellerman , Helge Deller , Russell King , Geert Uytterhoeven , Catalin Marinas , James Hogan , Firoz Khan , Matt Turner , Fenghua Yu , Arnd Bergmann , linux-m68k@lists.linux-m68k.org, Ivan Kokshaysky , linux-arm-kernel@lists.infradead.org, Richard Henderson , Michal Simek , Tony Luck , linux-parisc@vger.kernel.org, linux-kernel@vger.kernel.org, Ralf Baechle , Paul Burton , linux-alpha@vger.kernel.org, Martin Schwidefsky , Andrew Morton , linuxppc-dev@lists.ozlabs.org, "David S . Miller" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Jens, On Wed, Apr 03, 2019 at 07:49:26AM -0600, Jens Axboe wrote: > On 4/3/19 5:11 AM, Will Deacon wrote: > > will@autoplooker:~/liburing/test$ ./io_uring_register > > RELIMIT_MEMLOCK: 67108864 (67108864) > > [ 35.477875] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000070 > > [ 35.478969] Mem abort info: > > [ 35.479296] ESR = 0x96000004 > > [ 35.479785] Exception class = DABT (current EL), IL = 32 bits > > [ 35.480528] SET = 0, FnV = 0 > > [ 35.480980] EA = 0, S1PTW = 0 > > [ 35.481345] Data abort info: > > [ 35.481680] ISV = 0, ISS = 0x00000004 > > [ 35.482267] CM = 0, WnR = 0 > > [ 35.482618] user pgtable: 4k pages, 48-bit VAs, pgdp = (____ptrval____) > > [ 35.483486] [0000000000000070] pgd=0000000000000000 > > [ 35.484041] Internal error: Oops: 96000004 [#1] PREEMPT SMP > > [ 35.484788] Modules linked in: > > [ 35.485311] CPU: 113 PID: 3973 Comm: io_uring_regist Not tainted 5.1.0-rc3-00012-g40b114779944 #1 > > [ 35.486712] Hardware name: linux,dummy-virt (DT) > > [ 35.487450] pstate: 20400005 (nzCv daif +PAN -UAO) > > [ 35.488228] pc : link_pwq+0x10/0x60 > > [ 35.488794] lr : apply_wqattrs_commit+0xe0/0x118 > > [ 35.489550] sp : ffff000017e2bbc0 > > Huh, this looks odd, it's crashing inside the wq setup. Enabling KASAN seems to indicate a double-free, which may well be related. Will [ 149.890370] ================================================================== [ 149.891266] BUG: KASAN: double-free or invalid-free in io_sqe_files_unregister+0xa8/0x140 [ 149.892218] [ 149.892411] CPU: 113 PID: 3974 Comm: io_uring_regist Tainted: G B 5.1.0-rc3-00012-g40b114779944 #3 [ 149.893623] Hardware name: linux,dummy-virt (DT) [ 149.894169] Call trace: [ 149.894539] dump_backtrace+0x0/0x228 [ 149.895172] show_stack+0x14/0x20 [ 149.895747] dump_stack+0xe8/0x124 [ 149.896335] print_address_description+0x60/0x258 [ 149.897148] kasan_report_invalid_free+0x78/0xb8 [ 149.897936] __kasan_slab_free+0x1fc/0x228 [ 149.898641] kasan_slab_free+0x10/0x18 [ 149.899283] kfree+0x70/0x1f8 [ 149.899798] io_sqe_files_unregister+0xa8/0x140 [ 149.900574] io_ring_ctx_wait_and_kill+0x190/0x3c0 [ 149.901402] io_uring_release+0x2c/0x48 [ 149.902068] __fput+0x18c/0x510 [ 149.902612] ____fput+0xc/0x18 [ 149.903146] task_work_run+0xf0/0x148 [ 149.903778] do_notify_resume+0x554/0x748 [ 149.904467] work_pending+0x8/0x10 [ 149.905060] [ 149.905331] Allocated by task 3974: [ 149.905934] __kasan_kmalloc.isra.0.part.1+0x48/0xf8 [ 149.906786] __kasan_kmalloc.isra.0+0xb8/0xd8 [ 149.907531] kasan_kmalloc+0xc/0x18 [ 149.908134] __kmalloc+0x168/0x248 [ 149.908724] __arm64_sys_io_uring_register+0x2b8/0x15a8 [ 149.909622] el0_svc_common+0x100/0x258 [ 149.910281] el0_svc_handler+0x48/0xc0 [ 149.910928] el0_svc+0x8/0xc [ 149.911425] [ 149.911696] Freed by task 3974: [ 149.912242] __kasan_slab_free+0x114/0x228 [ 149.912955] kasan_slab_free+0x10/0x18 [ 149.913602] kfree+0x70/0x1f8 [ 149.914118] __arm64_sys_io_uring_register+0xc2c/0x15a8 [ 149.915009] el0_svc_common+0x100/0x258 [ 149.915670] el0_svc_handler+0x48/0xc0 [ 149.916317] el0_svc+0x8/0xc [ 149.916817] [ 149.917101] The buggy address belongs to the object at ffff8004ce07ed00 [ 149.917101] which belongs to the cache kmalloc-128 of size 128 [ 149.919197] The buggy address is located 0 bytes inside of [ 149.919197] 128-byte region [ffff8004ce07ed00, ffff8004ce07ed80) [ 149.921142] The buggy address belongs to the page: [ 149.921953] page:ffff7e0013381f00 count:1 mapcount:0 mapping:ffff800503417c00 index:0x0 compound_mapcount: 0 [ 149.923595] flags: 0x1ffff00000010200(slab|head) [ 149.924388] raw: 1ffff00000010200 dead000000000100 dead000000000200 ffff800503417c00 [ 149.925706] raw: 0000000000000000 0000000080400040 00000001ffffffff 0000000000000000 [ 149.927011] page dumped because: kasan: bad access detected [ 149.927956] [ 149.928224] Memory state around the buggy address: [ 149.929054] ffff8004ce07ec00: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc [ 149.930274] ffff8004ce07ec80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 149.931494] >ffff8004ce07ed00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 149.932712] ^ [ 149.933281] ffff8004ce07ed80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 149.934508] ffff8004ce07ee00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 149.935725] ================================================================== _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel