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=-17.6 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 C93ADC5B57D for ; Tue, 2 Jul 2019 07:00:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9324D21721 for ; Tue, 2 Jul 2019 07:00:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="PZgwS9aO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726305AbfGBHAZ (ORCPT ); Tue, 2 Jul 2019 03:00:25 -0400 Received: from mail-yb1-f202.google.com ([209.85.219.202]:37408 "EHLO mail-yb1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725775AbfGBHAY (ORCPT ); Tue, 2 Jul 2019 03:00:24 -0400 Received: by mail-yb1-f202.google.com with SMTP id z4so1899193ybo.4 for ; Tue, 02 Jul 2019 00:00:23 -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=DRpVxpKYEuhVQ2R7SXvDNRP8Do9Em+87V8id3oCDFg0=; b=PZgwS9aO0TUMKaUyLMaQ08y1R5wKrtrfeTsZft/tdNRlpG1bQhl0wCIa0MSvhqLO/x DUKgzxbLEUSPO7h7EjZUrRDafEqhMAHf/srGoP98SusnhKvPYGaWNx+MHDBITWIrsx7d UAcSLOth2oL+moRyxWTWA++LLec/YhqSAlKPdNoyKfQy84d2dmxBIqS9U1rLQ1B7RT/S Ewu0IRY19lEu7aGL0mf+jDQg+8f2ucWwW86tJXydAzETMzMi8Lqx+qAPfn7WQ7hfCmOE rOvBMYbUuG/0KzgnKLQvh4Vld4Guex5tsaT4VzEiU4NyxtulTiAQixJKLLyPNp+d431H PoEw== 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=DRpVxpKYEuhVQ2R7SXvDNRP8Do9Em+87V8id3oCDFg0=; b=P9deeQPnbNeq3JQ7YAxLp4d/1Xv3KW8AXLlXOkk78SyRe7GbS1yidmLnLn5HfQjijy RnLH7BD6bzMEO7nB/EwnEzx98KwpGy4Zb8jAQW+XshGNRDdMvDu78yiROSy4XMeRBHPO FTPi3YaYkSYOekipAyi/rAjfnTmWPxXN26SjuyWry45rgy8Xtvq0x2gnSgSQMVabF8qi XquRH5x++I8++XrtB2DVQcfP/KrZZ01yJyTq9R/OBh+pkbDTQijJkWtmyHx7l8PyKNLe ysc8s6+Aunq8OIsbblNrAsYM6peOFt2bGQlPsDJD6MSMXwRWsrarSLkPJJlVaq3zICir s3Xw== X-Gm-Message-State: APjAAAVNfYA9bpugPXk5OQGenbqztta5XvLxz0crG5Z5VeithdciUA3p MZL0ewMO7SQNp1QVjFHGLotcGda21RL9 X-Google-Smtp-Source: APXvYqyDtzJxwLv7clZEmERcM4T59nbfuEfsdMguD3bfLoL26yqqErhI7k5UvXjOsgmPiiMVmkY9Ia4g6Ep/ X-Received: by 2002:a0d:e1c1:: with SMTP id k184mr17335992ywe.153.1562050822661; Tue, 02 Jul 2019 00:00:22 -0700 (PDT) Date: Mon, 1 Jul 2019 23:59:49 -0700 In-Reply-To: <20190702065955.165738-1-irogers@google.com> Message-Id: <20190702065955.165738-2-irogers@google.com> Mime-Version: 1.0 References: <20190702065955.165738-1-irogers@google.com> X-Mailer: git-send-email 2.22.0.410.gd8fdbe21b5-goog Subject: [PATCH 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 | 38 +++++++++++++++++++++++++------------- 1 file changed, 25 insertions(+), 13 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 785d708f8553..4faa90f5a934 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -2558,11 +2558,12 @@ static int __perf_install_in_context(void *info) * * 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); @@ -2577,15 +2578,15 @@ 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 @@ -2619,8 +2620,9 @@ 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 err; raw_spin_lock_irq(&ctx->lock); task = ctx->task; @@ -2631,7 +2633,7 @@ 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, @@ -2643,6 +2645,7 @@ perf_install_in_context(struct perf_event_context *ctx, } add_event_to_ctx(event, ctx); raw_spin_unlock_irq(&ctx->lock); + return 0; } /* @@ -11103,7 +11106,9 @@ 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); } @@ -11113,7 +11118,9 @@ 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); } @@ -11128,7 +11135,8 @@ 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) @@ -11247,7 +11255,8 @@ 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); @@ -11270,6 +11279,7 @@ 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; @@ -11308,7 +11318,8 @@ 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); } @@ -11321,7 +11332,8 @@ 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); -- 2.22.0.410.gd8fdbe21b5-goog