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 BF25FC83F34 for ; Thu, 17 Jul 2025 15:40:01 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ucQhI-00063r-J6; Thu, 17 Jul 2025 11:39:00 -0400 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 1ucOif-0004CQ-9z for qemu-devel@nongnu.org; Thu, 17 Jul 2025 09:32:31 -0400 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 1ucOia-0005S6-RQ for qemu-devel@nongnu.org; Thu, 17 Jul 2025 09:32:15 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1752759131; 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:in-reply-to:in-reply-to: references:references; bh=eNBVz6pyTzXbqUirtLvfILjSOroKFt9aKYasabteA/k=; b=EkUDrXenhBP/pt6+Zwng3A5inGndPpHrsKblLuWx0L7vf011vuyL6+Z5yuKByqUDA142zp YeWuZPB9WOun7y/6UlZa5ui4/IS3hFSbsf8dkhhqjhCOB9QyMA4yLLHPdr52EO1i3SAYAT mgpi0qhhZ1ZEqy6DqIFr2niPEj+gKV8= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-195-qUCEYu6sMISrP6Sh0mWk6w-1; Thu, 17 Jul 2025 09:32:05 -0400 X-MC-Unique: qUCEYu6sMISrP6Sh0mWk6w-1 X-Mimecast-MFC-AGG-ID: qUCEYu6sMISrP6Sh0mWk6w_1752759124 Received: from mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.15]) (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-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 83FF018001D4; Thu, 17 Jul 2025 13:32:04 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.171]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 7BCB61956089; Thu, 17 Jul 2025 13:32:02 +0000 (UTC) Date: Thu, 17 Jul 2025 14:31:58 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Fabiano Rosas Cc: qemu-devel@nongnu.org, Peter Xu , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , Peter Maydell Subject: Re: [PATCH 1/2] migration: Fix postcopy latency distribution formatting computation Message-ID: References: <20250715124552.28038-1-farosas@suse.de> <20250715124552.28038-2-farosas@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20250715124552.28038-2-farosas@suse.de> User-Agent: Mutt/2.2.14 (2025-02-20) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 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: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, 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_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-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, Jul 15, 2025 at 09:45:51AM -0300, Fabiano Rosas wrote: > Coverity has caught a bug in the formatting of time intervals for > postcopy latency distribution display in 'info migrate'. > > While bounds checking the labels array, sizeof is incorrectly being > used. ARRAY_SIZE is the correct form of obtaining the size of an > array. > > Fixes: 3345fb3b6d ("migration/postcopy: Add latency distribution report for blocktime") > Resolves: Coverity CID 1612248 > Suggested-by: Peter Maydell > Signed-off-by: Fabiano Rosas > --- > migration/migration-hmp-cmds.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/migration/migration-hmp-cmds.c b/migration/migration-hmp-cmds.c > index cef5608210..bb954881d7 100644 > --- a/migration/migration-hmp-cmds.c > +++ b/migration/migration-hmp-cmds.c > @@ -57,11 +57,9 @@ static const gchar *format_time_str(uint64_t us) > const char *units[] = {"us", "ms", "sec"}; > int index = 0; > > - while (us > 1000) { > + while (us > 1000 && index + 1 < ARRAY_SIZE(units)) { > us /= 1000; > - if (++index >= (sizeof(units) - 1)) { > - break; > - } > + index++; > } > > return g_strdup_printf("%"PRIu64" %s", us, units[index]); It occurrs to me that this is the same basic algorithmic problem as converting storage sizes from bytes to KB/MB/GB/etc. We have size_to_str() which does this conversion without needing any loop at all. Then there is freq_to_str() which has similar purpose but still uses a loop, instead of the shortcut size_to_str has. IMHO we should have a 'scaled_int_to_str' method that is common to any place we need such scaled integer string conversions, and then wrappers like "size_to_str", "freq_to_str" and "duration_to_str" that pass in the required list of unit strings, and the divisor and requested decimal precision, etc. 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 :|