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=-17.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL 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 73B6FC76186 for ; Wed, 24 Jul 2019 22:38:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3E88121911 for ; Wed, 24 Jul 2019 22:38:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="XmXePXfJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387712AbfGXWif (ORCPT ); Wed, 24 Jul 2019 18:38:35 -0400 Received: from mail-qt1-f201.google.com ([209.85.160.201]:38328 "EHLO mail-qt1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387405AbfGXWie (ORCPT ); Wed, 24 Jul 2019 18:38:34 -0400 Received: by mail-qt1-f201.google.com with SMTP id r58so42861303qtb.5 for ; Wed, 24 Jul 2019 15:38:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=BHNx3fxgIAaIZGtj0Y4teHviUd3zpJGTp0ZxFmiQ/M0=; b=XmXePXfJ2+b7OUYzjP8p2v6gnrwa5zdmWN8+PDRLb8CqPxvZ22ID60Gv59vneL7oTf KckiJ5iuorOO5+NLBP3dzRW4snrMCDzGoSE15J1dBmz1xhbCSIm5c4OZLnquNY15UrUq lImHlPD5pLZCsxebTLqvl44y8N+f9qOm9FJJBG5KseIbB5i9R/tsWo7fCSyRB4bCsgVv Uybu1AXXlMuebS8GiNjJ/sxQFpn4yHDnikQCckjHWRUkEPRtnwlw61ZwIx8eNwK0fK2p mK8Mq9GF97FXQpHNVs20nzs/xHIVFZA2wCw4V/uZAGOG0nqbz/44qxrmmgyOEMbF+Vwg jCXw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=BHNx3fxgIAaIZGtj0Y4teHviUd3zpJGTp0ZxFmiQ/M0=; b=O4l5DT+i3ou9aO2dpeXh+yE+4VR+tQPMZaDGL7LF5DfAvzMm9gEr3duX2Bb1Oy1EdS hH5rUZtQYJ2NaP3E/qINSfABnH3heHunGnoDzeXbCGULEczvoKIXsaNCw0JJGr2uG9wf 8XEqs2/OxY/h2DjleN5aSuG+/4YhKFYRRRa6EhkSp8y7bV9IHxaeIZ/v6CrOnrGO9o+j krdnFwUQzlEAAk6y7MVYoe1G+nPnIg7g7W3+DAbzJETXZPBkfVZzWcVHd9tuoirqGdvl aDDeA0eiRJih4iJKgJ0FPPjf7TMW+AI0FrLM5AnoQL//ooGdz9Rbq+TyBZsYeaQkGpas mLrA== X-Gm-Message-State: APjAAAWQWYx6umn4Veo7qTmSq1kkjChX14xplK8chwuUZLSUyhqR0aqx i3V8WMA2CoyHmSD4eOKnlYsXiFXylKgI X-Google-Smtp-Source: APXvYqzS8EaBfAyHfmhTPGBmLpocc3q6DpRU2TN+O6nBia67EsTg1jvOZNjuKclRFnUX5YSY/7abG8O0GWqZ X-Received: by 2002:a0c:ba0b:: with SMTP id w11mr61057366qvf.71.1564007913001; Wed, 24 Jul 2019 15:38:33 -0700 (PDT) Date: Wed, 24 Jul 2019 15:37:40 -0700 In-Reply-To: <20190724223746.153620-1-irogers@google.com> Message-Id: <20190724223746.153620-2-irogers@google.com> Mime-Version: 1.0 References: <20190702065955.165738-1-irogers@google.com> <20190724223746.153620-1-irogers@google.com> X-Mailer: git-send-email 2.22.0.709.g102302147b-goog Subject: [PATCH v2 1/7] perf: propagate perf_install_in_context errors up From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Alexander Shishkin , Jiri Olsa , Namhyung Kim , linux-kernel@vger.kernel.org Cc: Kan Liang , Stephane Eranian , Ian Rogers Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The current __perf_install_in_context can fail and the error is ignored. Changing __perf_install_in_context can add new failure modes that need errors propagating up. This change prepares for this. Signed-off-by: Ian Rogers --- kernel/events/core.c | 39 ++++++++++++++++++++++++++------------- 1 file changed, 26 insertions(+), 13 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index eea9d52b010c..84a22a5c88b0 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -2561,11 +2561,12 @@ static bool exclusive_event_installable(struct perf_event *event, * * Very similar to event_function_call, see comment there. */ -static void +static int perf_install_in_context(struct perf_event_context *ctx, struct perf_event *event, int cpu) { + int err; struct task_struct *task = READ_ONCE(ctx->task); lockdep_assert_held(&ctx->mutex); @@ -2582,15 +2583,15 @@ perf_install_in_context(struct perf_event_context *ctx, smp_store_release(&event->ctx, ctx); if (!task) { - cpu_function_call(cpu, __perf_install_in_context, event); - return; + err = cpu_function_call(cpu, __perf_install_in_context, event); + return err; } /* * Should not happen, we validate the ctx is still alive before calling. */ if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) - return; + return 0; /* * Installing events is tricky because we cannot rely on ctx->is_active @@ -2624,9 +2625,11 @@ perf_install_in_context(struct perf_event_context *ctx, */ smp_mb(); again: - if (!task_function_call(task, __perf_install_in_context, event)) - return; + err = task_function_call(task, __perf_install_in_context, event); + if (!err) + return 0; + WARN_ON_ONCE(err != -ESRCH); raw_spin_lock_irq(&ctx->lock); task = ctx->task; if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) { @@ -2636,7 +2639,7 @@ perf_install_in_context(struct perf_event_context *ctx, * against perf_event_exit_task_context(). */ raw_spin_unlock_irq(&ctx->lock); - return; + return 0; } /* * If the task is not running, ctx->lock will avoid it becoming so, @@ -2648,6 +2651,7 @@ perf_install_in_context(struct perf_event_context *ctx, } add_event_to_ctx(event, ctx); raw_spin_unlock_irq(&ctx->lock); + return 0; } /* @@ -11130,7 +11134,9 @@ SYSCALL_DEFINE5(perf_event_open, */ for_each_sibling_event(sibling, group_leader) { perf_event__state_init(sibling); - perf_install_in_context(ctx, sibling, sibling->cpu); + err = perf_install_in_context(ctx, sibling, + sibling->cpu); + WARN_ON_ONCE(err); get_ctx(ctx); } @@ -11140,7 +11146,9 @@ SYSCALL_DEFINE5(perf_event_open, * startup state, ready to be add into new context. */ perf_event__state_init(group_leader); - perf_install_in_context(ctx, group_leader, group_leader->cpu); + err = perf_install_in_context(ctx, group_leader, + group_leader->cpu); + WARN_ON_ONCE(err); get_ctx(ctx); } @@ -11155,7 +11163,8 @@ SYSCALL_DEFINE5(perf_event_open, event->owner = current; - perf_install_in_context(ctx, event, event->cpu); + err = perf_install_in_context(ctx, event, event->cpu); + WARN_ON_ONCE(err); perf_unpin_context(ctx); if (move_group) @@ -11274,7 +11283,8 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, goto err_unlock; } - perf_install_in_context(ctx, event, cpu); + err = perf_install_in_context(ctx, event, cpu); + WARN_ON_ONCE(err); perf_unpin_context(ctx); mutex_unlock(&ctx->mutex); @@ -11297,6 +11307,7 @@ void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu) struct perf_event_context *dst_ctx; struct perf_event *event, *tmp; LIST_HEAD(events); + int err; src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx; dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx; @@ -11335,7 +11346,8 @@ void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu) if (event->state >= PERF_EVENT_STATE_OFF) event->state = PERF_EVENT_STATE_INACTIVE; account_event_cpu(event, dst_cpu); - perf_install_in_context(dst_ctx, event, dst_cpu); + err = perf_install_in_context(dst_ctx, event, dst_cpu); + WARN_ON_ONCE(err); get_ctx(dst_ctx); } @@ -11348,7 +11360,8 @@ void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu) if (event->state >= PERF_EVENT_STATE_OFF) event->state = PERF_EVENT_STATE_INACTIVE; account_event_cpu(event, dst_cpu); - perf_install_in_context(dst_ctx, event, dst_cpu); + err = perf_install_in_context(dst_ctx, event, dst_cpu); + WARN_ON_ONCE(err); get_ctx(dst_ctx); } mutex_unlock(&dst_ctx->mutex); -- 2.22.0.709.g102302147b-goog