From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-f41.google.com ([209.85.215.41]:36644 "EHLO mail-lf0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751366AbcBUTCh (ORCPT ); Sun, 21 Feb 2016 14:02:37 -0500 Received: by mail-lf0-f41.google.com with SMTP id 78so81507183lfy.3 for ; Sun, 21 Feb 2016 11:02:37 -0800 (PST) Subject: Re: [PATCH] MIPS: vdso: flush the vdso data page to update it on all processes To: Hauke Mehrtens , linux-mips@linux-mips.org, ralf@linux-mips.org References: <1456059443-13889-1-git-send-email-hauke@hauke-m.de> Cc: alex.smith@imgtec.com, "# v4 . 4+" From: Sergei Shtylyov Message-ID: <56C9B943.1080006@cogentembedded.com> Date: Sun, 21 Feb 2016 16:18:59 +0300 MIME-Version: 1.0 In-Reply-To: <1456059443-13889-1-git-send-email-hauke@hauke-m.de> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: stable-owner@vger.kernel.org List-ID: Hello. On 2/21/2016 3:57 PM, Hauke Mehrtens wrote: > Without flushing the vdso data page the vdso call is working on dated > or unsynced data. This resulted in problems where the clock_gettime > vdso call returned a time 6 seconds later after a 3 sounds sleep, > while the syscall reported a time 3 sounds later like expected. This s/sounds/seconds/ perhaps? > happened very often and I got these ping results for example: > > root@OpenWrt:/# ping 192.168.1.255 > PING 192.168.1.255 (192.168.1.255): 56 data bytes > 64 bytes from 192.168.1.3: seq=0 ttl=64 time=0.688 ms > 64 bytes from 192.168.1.3: seq=1 ttl=64 time=4294172.045 ms > 64 bytes from 192.168.1.3: seq=2 ttl=64 time=4293968.105 ms > 64 bytes from 192.168.1.3: seq=3 ttl=64 time=4294055.920 ms > 64 bytes from 192.168.1.3: seq=4 ttl=64 time=4294671.913 ms > > The flush is now done like it is done on the arm architecture code. > > This was tested on a Lantiq/Intel VRX288 (MIPS BE 34Kc V5.6 CPU with > two VPEs) > > Signed-off-by: Hauke Mehrtens > Cc: # v4.4+ [...] MBR, Sergei