From nobody Mon Apr 6 09:41:25 2026 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6DE36C38145 for ; Thu, 8 Sep 2022 19:57:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229455AbiIHT5f (ORCPT ); Thu, 8 Sep 2022 15:57:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43184 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229651AbiIHT5W (ORCPT ); Thu, 8 Sep 2022 15:57:22 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 28843FDBA3 for ; Thu, 8 Sep 2022 12:57:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1662667040; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=JcghkbSjULMePVbzbb4JaxRiOu/Uf2FtD3sfj5LZVkY=; b=cHa49sv3fkI7hTHTiyFhaGQbK2Tm1UFHNh0rAyhbRrAj5uahOVl/DBFDVtB3PazSCRY/NE gccRFMFYeUEj14JSZdxa8rRegGxf0xPV42I/R6pbY4EW6JRPhgf9B4i0vMq2sxpttBSsQb u8nvzo3O+UwMBFFqsLuy2sccwFkIKIg= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-411-7U62WPpDN0OgBWAW-PRmqQ-1; Thu, 08 Sep 2022 15:57:16 -0400 X-MC-Unique: 7U62WPpDN0OgBWAW-PRmqQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 773313C0CD59; Thu, 8 Sep 2022 19:57:16 +0000 (UTC) Received: from fuller.cnet (ovpn-112-2.gru2.redhat.com [10.97.112.2]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 44D85112131E; Thu, 8 Sep 2022 19:57:16 +0000 (UTC) Received: by fuller.cnet (Postfix, from userid 1000) id 27B84418859B; Thu, 8 Sep 2022 16:54:07 -0300 (-03) Message-ID: <20220908195111.915923599@redhat.com> User-Agent: quilt/0.66 Date: Thu, 08 Sep 2022 16:29:05 -0300 From: Marcelo Tosatti To: linux-kernel@vger.kernel.org Cc: Frederic Weisbecker , Juri Lelli , Daniel Bristot de Oliveira , Prasad Pandit , Valentin Schneider , Yair Podemsky , Thomas Gleixner , Marcelo Tosatti Subject: [RFC PATCH 6/7] perf_event_open: check for block interference CPUs References: <20220908192859.546633738@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" When creating perf events, return an error rather than interfering with CPUs tagged as block interference. Note: this patch is incomplete, installation of perf context=20 on block interference CPUs via task context is not performed. Signed-off-by: Marcelo Tosatti Index: linux-2.6/kernel/events/core.c =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- linux-2.6.orig/kernel/events/core.c +++ linux-2.6/kernel/events/core.c @@ -54,6 +54,7 @@ #include #include #include +#include =20 #include "internal.h" =20 @@ -12391,6 +12392,26 @@ not_move_group: =20 WARN_ON_ONCE(ctx->parent_ctx); =20 + block_interf_read_lock(); + if (!task) { + if (move_group) { + for_each_sibling_event(sibling, group_leader) { + if (block_interf_cpu(sibling->cpu)) { + err =3D -EPERM; + goto err_block_interf; + } + } + if (block_interf_cpu(group_leader->cpu)) { + err =3D -EPERM; + goto err_block_interf; + } + } + if (block_interf_cpu(event->cpu)) { + err =3D -EPERM; + goto err_block_interf; + } + } + /* * This is the point on no return; we cannot fail hereafter. This is * where we start modifying current state. @@ -12464,6 +12485,8 @@ not_move_group: put_task_struct(task); } =20 + block_interf_read_unlock(); + mutex_lock(¤t->perf_event_mutex); list_add_tail(&event->owner_entry, ¤t->perf_event_list); mutex_unlock(¤t->perf_event_mutex); @@ -12478,6 +12501,8 @@ not_move_group: fd_install(event_fd, event_file); return event_fd; =20 +err_block_interf: + block_interf_read_unlock(); err_locked: if (move_group) perf_event_ctx_unlock(group_leader, gctx);