From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Priebe Subject: Re: kernel 4.4.2: kvm_irq_delivery_to_api / rwsem_down_read_failed Date: Mon, 22 Feb 2016 20:35:41 +0100 Message-ID: <56CB630D.8080302@profihost.ag> References: <56C8439F.5070901@profihost.ag> <56CB4705.1090303@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit To: Paolo Bonzini , qemu-devel , kvm@vger.kernel.org Return-path: Received: from mail-ph.de-nserver.de ([85.158.179.214]:36385 "EHLO mail-ph.de-nserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751179AbcBVTe2 (ORCPT ); Mon, 22 Feb 2016 14:34:28 -0500 In-Reply-To: <56CB4705.1090303@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Am 22.02.2016 um 18:36 schrieb Paolo Bonzini: > > > On 20/02/2016 11:44, Stefan Priebe wrote: >> Hi, >> >> while testing Kernel 4.4.2 and starting 20 Qemu 2.4.1 virtual machines. >> I got those traces and a load of 500 on those system. I was only abler >> to recover by sysrq-trigger. > > It seems like something happening at the VM level. A task took the mm > semaphore and hung everyone else. Difficult to debug without a core > (and without knowing who held the semaphore). Sorry. OK thank you anyway. Is there anything i can do if this happens again? Stefan > Paolo > > >> All traces: >> >> INFO: task pvedaemon worke:7470 blocked for more than 120 seconds. >> Not tainted 4.4.2+1-ph #1 >> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. >> pvedaemon worke D ffff88239c367ca0 0 7470 7468 0x00080000 >> ffff88239c367ca0 ffff8840a6232500 ffff8823ed83a500 ffff88239c367c90 >> ffff88239c368000 ffff8845f5f070e8 ffff8845f5f07100 0000000000000000 >> 00007ffc73b48e58 ffff88239c367cc0 ffffffffb66a4d89 ffff88239c367cf0 >> Call Trace: >> [] schedule+0x39/0x80 >> [] rwsem_down_read_failed+0xc7/0x120 >> [] call_rwsem_down_read_failed+0x14/0x30 >> [] ? down_read+0x17/0x20 >> [] __access_remote_vm+0x3e/0x1c0 >> [] ? call_rwsem_down_read_failed+0x14/0x30 >> [] access_remote_vm+0x1f/0x30 >> [] proc_pid_cmdline_read+0x16e/0x4f0 >> [] ? acct_account_cputime+0x1c/0x20 >> [] __vfs_read+0x18/0x40 >> [] vfs_read+0x8e/0x140 >> [] SyS_read+0x4f/0xa0 >> [] entry_SYSCALL_64_fastpath+0x12/0x71 >> INFO: task pvestatd:7633 blocked for more than 120 seconds. >> Not tainted 4.4.2+1-ph #1 >> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. >> pvestatd D ffff88239f16fd40 0 7633 1 0x00080000 >> ffff88239f16fd40 ffff8824e76a8000 ffff8823e5fc2500 ffff8823e5fc2500 >> ffff88239f170000 ffff8845f5f070e8 ffff8845f5f07100 ffff8845f5f07080 >> 000000000341bf10 ffff88239f16fd60 ffffffffb66a4d89 024000d000000058 >> Call Trace: >> [] schedule+0x39/0x80 >> [] rwsem_down_read_failed+0xc7/0x120 >> [] call_rwsem_down_read_failed+0x14/0x30 >> [] ? down_read+0x17/0x20 >> [] proc_pid_cmdline_read+0xac/0x4f0 >> [] ? acct_account_cputime+0x1c/0x20 >> [] ? account_user_time+0x73/0x80 >> [] ? vtime_account_user+0x4e/0x70 >> [] __vfs_read+0x18/0x40 >> [] vfs_read+0x8e/0x140 >> [] SyS_read+0x4f/0xa0 >> [] entry_SYSCALL_64_fastpath+0x12/0x71