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=-6.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 F1903C10DCE for ; Sat, 14 Mar 2020 00:10:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BFA9D2074B for ; Sat, 14 Mar 2020 00:10:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="UkdDesbX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727628AbgCNAKm (ORCPT ); Fri, 13 Mar 2020 20:10:42 -0400 Received: from mail-qt1-f196.google.com ([209.85.160.196]:46776 "EHLO mail-qt1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726534AbgCNAKm (ORCPT ); Fri, 13 Mar 2020 20:10:42 -0400 Received: by mail-qt1-f196.google.com with SMTP id t13so9205085qtn.13; Fri, 13 Mar 2020 17:10:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=fFSXCfPxZ44Gnna3dml1rVBvXL2ix7ceGBfMvBZcWhM=; b=UkdDesbXxDUbg/DWkkM7sHPh9FhVdTbptkUsIMGIMH8oIJNK4CeqEW4mizy05MukkY Wts6bS3oPfdRBlMrUsN0XD4L2kySfaN64YKwJ0rmfz0Tts1ja6sF4BaI5RLHjeRHsxY5 5dzmJ+ieanG7C0Yf/ZkYE+m6/fxyTbNNEIkqUSsTFOMdlL8DrQBXKITZo4BzAA1L/Npo Z4oyOe7k7HnUy4qrGzofXI167Rv8R68BKgMqg/bzyvFDJavhol2wui3184MjBgzvVHrh wQQqz5n7vN/wa8A29HqU75LAXCtJjWupVgN01of7YFROdlA6sx0B/ZGNOnrJqfFYjIlA /cgA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=fFSXCfPxZ44Gnna3dml1rVBvXL2ix7ceGBfMvBZcWhM=; b=iqy5WEYIGwThoWj/8l4++ruAWy5BnBF3Y0CPMsu/HrTCUSDXXuHeqJPj6gtEK2zhTM n23DbHxbm04T2Q4DlRPqxDJ/+jd4ahIqRS7Qz2ic5AJ9m6FYyhru/l3jkma8OuWVxTuK i3sVBPrfy4deDXNRFunNNRiKwluGRCc07kHEQdepTz+Zbmu6FCVBgR5V/8ITyuSEFj/G wdf3jtCTBR4JLoWw5LheEjyEGPNZf12yFvUBHQmzHmAjv7BIbNH9Z908SS0H1y2GgW3C T5w8US2UZJBWhmExcofBAd0RGCx5lecjIiUitTo/9N4ijAhJe8O5iFSwKe0hYekvcpqu mIGA== X-Gm-Message-State: ANhLgQ1l7nsWXetQhPjbJCnEcypE5fMHX+B5HitUUpdyebgxPpdNfBJm vXE/B1pA06s7O/oME2OeGanVH9owmXnMyf3ZS+Y= X-Google-Smtp-Source: ADFU+vsgImTQTIJZ5OGL/TViJc/xh0JVJ3pvrUibZAduISBqK1IMILlfRzrNz6b8LLekW4ilQ2KdjtG5wDQH8gCM6Ho= X-Received: by 2002:ac8:4e14:: with SMTP id c20mr14992805qtw.141.1584144640839; Fri, 13 Mar 2020 17:10:40 -0700 (PDT) MIME-Version: 1.0 References: <20200313233535.3557677-1-andriin@fb.com> <20200314000510.cmsepdhnywtglrcm@kafai-mbp> In-Reply-To: <20200314000510.cmsepdhnywtglrcm@kafai-mbp> From: Andrii Nakryiko Date: Fri, 13 Mar 2020 17:10:29 -0700 Message-ID: Subject: Re: [Potential Spoof] [PATCH bpf-next] selftests/bpf: fix nanosleep for real this time To: Martin KaFai Lau Cc: Andrii Nakryiko , bpf , Networking , Alexei Starovoitov , Daniel Borkmann , Kernel Team Content-Type: text/plain; charset="UTF-8" Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Fri, Mar 13, 2020 at 5:05 PM Martin KaFai Lau wrote: > > On Fri, Mar 13, 2020 at 04:35:35PM -0700, Andrii Nakryiko wrote: > > Amazingly, some libc implementations don't call __NR_nanosleep syscall from > > their nanosleep() APIs. Hammer it down with explicit syscall() call and never > > get back to it again. Also simplify code for timespec initialization. > > > > I verified that nanosleep is called w/ printk and in exactly same Linux image > > that is used in Travis CI. So it should both sleep and call correct syscall. > > > > Fixes: 4e1fd25d19e8 ("selftests/bpf: Fix usleep() implementation") > > Signed-off-by: Andrii Nakryiko > > --- > > tools/testing/selftests/bpf/test_progs.c | 16 ++++++---------- > > 1 file changed, 6 insertions(+), 10 deletions(-) > > > > diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c > > index f85a06512541..6956d722a463 100644 > > --- a/tools/testing/selftests/bpf/test_progs.c > > +++ b/tools/testing/selftests/bpf/test_progs.c > > @@ -35,16 +35,12 @@ struct prog_test_def { > > */ > > int usleep(useconds_t usec) > > { > > - struct timespec ts; > > - > > - if (usec > 999999) { > > - ts.tv_sec = usec / 1000000; > > - ts.tv_nsec = usec % 1000000; > > - } else { > > - ts.tv_sec = 0; > > - ts.tv_nsec = usec; > > - } > > - return nanosleep(&ts, NULL); > > + struct timespec ts = { > > + .tv_sec = usec / 1000000, > > + .tv_nsec = usec % 1000000, > usec is in micro and tv_nsec is in nano? > Yes, this is implementation of usleep() (microsecond sleep), so usec is microseconds. We call nanosleep internally, though, which accepts seconds and nanoseconds units. Did I mess up math here? But either way, sending v2, there is another place we explicitly are calling nanosleep as well, fixing that one as well. > > + }; > > + > > + return syscall(__NR_nanosleep, &ts, NULL); > > } > >