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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id AE48BE77198 for ; Tue, 7 Jan 2025 12:43:03 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tV8ud-0007Bi-00; Tue, 07 Jan 2025 07:42:24 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tV8uY-0007BE-Db for qemu-devel@nongnu.org; Tue, 07 Jan 2025 07:42:19 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tV8uV-0004E7-RV for qemu-devel@nongnu.org; Tue, 07 Jan 2025 07:42:17 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1736253734; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=qfVJMxLX0yK3zBExqW0wBPdz2eGbMTcGtktm1jzQd1o=; b=Ns80one5/gJrV4O46dJNTvo5YRCGpvQqJp/CFXKpdoeNBPjL44ehaSmxxqY7rsHpXs7ecL 8IbFTlnJM4hTw1bIgUrCqawkZY+nMYVOgxUUFzxMAeXhIXy7zHh2wACIXkXFyEzWjNBg/q eraJw9t1TpWvRb7KGtiU0cWGg5mUZwo= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-583-tCWu2IlBPvaiGG-YC0EGQg-1; Tue, 07 Jan 2025 07:42:10 -0500 X-MC-Unique: tCWu2IlBPvaiGG-YC0EGQg-1 X-Mimecast-MFC-AGG-ID: tCWu2IlBPvaiGG-YC0EGQg Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.40]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 6C0F51956046; Tue, 7 Jan 2025 12:42:09 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.64]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 8B9261955EB4; Tue, 7 Jan 2025 12:42:07 +0000 (UTC) Date: Tue, 7 Jan 2025 12:42:03 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Thomas Huth Cc: Stefan Hajnoczi , qemu-devel@nongnu.org, Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , Peter Maydell Subject: Re: [PATCH] tests/functional/test_x86_64_hotplug_cpu: Fix race condition during unplug Message-ID: References: <20250107115245.52755-1-thuth@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/2.2.13 (2024-03-09) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -24 X-Spam_score: -2.5 X-Spam_bar: -- X-Spam_report: (-2.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.437, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Tue, Jan 07, 2025 at 01:03:52PM +0100, Thomas Huth wrote: > On 07/01/2025 12.57, Daniel P. Berrangé wrote: > > On Tue, Jan 07, 2025 at 12:52:45PM +0100, Thomas Huth wrote: > > > When unplugging the CPU, the test tries to check for a successful > > > unplug by changing to the /sys/devices/system/cpu/cpu1 directory > > > to see whether that fails. However, the "cd" could be faster than > > > the unplug operation in the kernel, so there is a race condition > > > and the test sometimes fails here. > > > Fix it by trying to change the directory in a loop until the the > > > CPU has really been unplugged. > > > > > > Reported-by: Stefan Hajnoczi > > > Signed-off-by: Thomas Huth > > > --- > > > tests/functional/test_x86_64_hotplug_cpu.py | 6 ++++-- > > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > > > > diff --git a/tests/functional/test_x86_64_hotplug_cpu.py b/tests/functional/test_x86_64_hotplug_cpu.py > > > index b1d5156c72..7b9200ac2e 100755 > > > --- a/tests/functional/test_x86_64_hotplug_cpu.py > > > +++ b/tests/functional/test_x86_64_hotplug_cpu.py > > > @@ -59,11 +59,13 @@ def test_hotplug(self): > > > 'cd /sys/devices/system/cpu/cpu1', > > > 'cpu1#') > > > + exec_command_and_wait_for_pattern(self, 'cd ..', prompt) > > > > Is this actually needed ? Are we keeping the CPU from being unplugged by > > being in that dir ? If so, why isn't it also needed in the while loop > > below ? > > I added it to make the console output less confusing (otherwise it's still > shown in the prompt after the CPU has been unplugged)... but I can also > remove this line again if you prefer it? No, i'm not that fussed. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|