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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 9C5C6ECDE20 for ; Wed, 11 Sep 2019 07:19:03 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 6C7262089F for ; Wed, 11 Sep 2019 07:19:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6C7262089F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernelpath.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:47291 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i7wu6-0003ku-Fk for qemu-devel@archiver.kernel.org; Wed, 11 Sep 2019 03:19:02 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:45192) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i7wrT-0001gZ-Mp for qemu-devel@nongnu.org; Wed, 11 Sep 2019 03:16:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1i7wrS-0001AR-D5 for qemu-devel@nongnu.org; Wed, 11 Sep 2019 03:16:19 -0400 Received: from indium.canonical.com ([91.189.90.7]:46138) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1i7wrS-00018x-84 for qemu-devel@nongnu.org; Wed, 11 Sep 2019 03:16:18 -0400 Received: from loganberry.canonical.com ([91.189.90.37]) by indium.canonical.com with esmtp (Exim 4.86_2 #2 (Debian)) id 1i7wrP-0001Uj-Oz for ; Wed, 11 Sep 2019 07:16:15 +0000 Received: from loganberry.canonical.com (localhost [127.0.0.1]) by loganberry.canonical.com (Postfix) with ESMTP id BA98C2E80C9 for ; Wed, 11 Sep 2019 07:16:15 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Date: Wed, 11 Sep 2019 07:05:41 -0000 From: Rafael David Tinoco To: qemu-devel@nongnu.org X-Launchpad-Notification-Type: bug X-Launchpad-Bug: product=qemu; status=In Progress; importance=Undecided; assignee=rafaeldtinoco@kernelpath.com; X-Launchpad-Bug: distribution=ubuntu; sourcepackage=qemu; component=main; status=In Progress; importance=Medium; assignee=rafaeldtinoco@kernelpath.com; X-Launchpad-Bug-Tags: qemu-img X-Launchpad-Bug-Information-Type: Public X-Launchpad-Bug-Private: no X-Launchpad-Bug-Security-Vulnerability: no X-Launchpad-Bug-Commenters: dannf jnsnow lizhengui rafaeldtinoco X-Launchpad-Bug-Reporter: dann frazier (dannf) X-Launchpad-Bug-Modifier: Rafael David Tinoco (rafaeldtinoco) References: <154327283728.15443.11625169757714443608.malonedeb@soybean.canonical.com> Message-Id: X-Launchpad-Message-Rationale: Subscriber (QEMU) @qemu-devel-ml X-Launchpad-Message-For: qemu-devel-ml Precedence: bulk X-Generated-By: Launchpad (canonical.com); Revision="19044"; Instance="production-secrets-lazr.conf" X-Launchpad-Hash: cd93aa51b4b635f8069961ed2ce2552153499142 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 91.189.90.7 Subject: [Qemu-devel] [Bug 1805256] Re: qemu_futex_wait() lockups in ARM64: 2 possible issues X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Bug 1805256 <1805256@bugs.launchpad.net> Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Message-ID: <20190911070541.6tcAZSFPvX65xG3PVMKNiEoddDsHwCBryx90bqLKwlI@z> Quick update... > value INT_MAX (4294967295) seems WRONG for qemu_futex_wait(): > = > - EV_BUSY, being -1, and passed as an argument qemu_futex_wait(void *, > unsigned), is a two's complement, making argument into a INT_MAX when > that's not what is expected (unless I missed something). > = > *** If that is the case, unsure if you, Paolo, prefer declaring > *(QemuEvent)->value as an integer or changing EV_BUSY to "2" would okay > here *** > = > BUG: description: > https://bugs.launchpad.net/qemu/+bug/1805256/comments/15 I realized this might be intentional, but, still, I tried: https://pastebin.ubuntu.com/p/6rkkY6fJdm/ looking for anything that could have misbehaved in arm64 (specially concerned on casting and type conversions between the functions). > QUESTION: > = > - Should qemu_event_set() check return code from > qemu_futex_wake()->qemu_futex()->syscall() in order to know if ANY > waiter was ever woken up ? Maybe even loop until at least 1 is awaken ? And I also tried: - qemu_futex(f, FUTEX_WAKE, n, NULL, NULL, 0); + while(qemu_futex(pval, FUTEX_WAKE, val, NULL, NULL, 0) =3D=3D 0) + continue; and it made little difference (took way more time for me to reproduce the issue though): """ (gdb) run Starting program: /usr/bin/qemu-img convert -f qcow2 -O qcow2 ./disk01.ext4.qcow2 ./output.qcow2 [New Thread 0xffffbec5ad90 (LWP 72839)] [New Thread 0xffffbe459d90 (LWP 72840)] [New Thread 0xffffbdb57d90 (LWP 72841)] [New Thread 0xffffacac9d90 (LWP 72859)] [New Thread 0xffffa7ffed90 (LWP 72860)] [New Thread 0xffffa77fdd90 (LWP 72861)] [New Thread 0xffffa6ffcd90 (LWP 72862)] [New Thread 0xffffa67fbd90 (LWP 72863)] [New Thread 0xffffa5ffad90 (LWP 72864)] [Thread 0xffffa5ffad90 (LWP 72864) exited] [Thread 0xffffa6ffcd90 (LWP 72862) exited] [Thread 0xffffa77fdd90 (LWP 72861) exited] [Thread 0xffffbdb57d90 (LWP 72841) exited] [Thread 0xffffa67fbd90 (LWP 72863) exited] [Thread 0xffffacac9d90 (LWP 72859) exited] [Thread 0xffffa7ffed90 (LWP 72860) exited] """ All the tasks left are blocked in a system call, so no task left to call qemu_futex_wake() to unblock thread #2 (in futex()), which would unblock thread #1 (doing poll() in a pipe with thread #2). Those 7 threads exit before disk conversion is complete (sometimes in the beginning, sometimes at the end). I'll try to check why those tasks exited. Any thoughts ? Tks -- = You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1805256 Title: qemu-img hangs on rcu_call_ready_event logic in Aarch64 when converting images Status in QEMU: In Progress Status in qemu package in Ubuntu: In Progress Bug description: On the HiSilicon D06 system - a 96 core NUMA arm64 box - qemu-img frequently hangs (~50% of the time) with this command: qemu-img convert -f qcow2 -O qcow2 /tmp/cloudimg /tmp/cloudimg2 Where "cloudimg" is a standard qcow2 Ubuntu cloud image. This qcow2->qcow2 conversion happens to be something uvtool does every time it fetches images. Once hung, attaching gdb gives the following backtrace: (gdb) bt #0 0x0000ffffae4f8154 in __GI_ppoll (fds=3D0xaaaae8a67dc0, nfds=3D187650= 274213760, = timeout=3D, timeout@entry=3D0x0, sigmask=3D0xffffc123b= 950) at ../sysdeps/unix/sysv/linux/ppoll.c:39 #1 0x0000aaaabbefaf00 in ppoll (__ss=3D0x0, __timeout=3D0x0, __nfds=3D, = __fds=3D) at /usr/include/aarch64-linux-gnu/bits/poll2= .h:77 #2 qemu_poll_ns (fds=3D, nfds=3D, = timeout=3Dtimeout@entry=3D-1) at util/qemu-timer.c:322 #3 0x0000aaaabbefbf80 in os_host_main_loop_wait (timeout=3D-1) at util/main-loop.c:233 #4 main_loop_wait (nonblocking=3D) at util/main-loop.c:497 #5 0x0000aaaabbe2aa30 in convert_do_copy (s=3D0xffffc123bb58) at qemu-im= g.c:1980 #6 img_convert (argc=3D, argv=3D) at qemu-= img.c:2456 #7 0x0000aaaabbe2333c in main (argc=3D7, argv=3D) at qemu= -img.c:4975 Reproduced w/ latest QEMU git (@ 53744e0a182) To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1805256/+subscriptions