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=-9.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 A3E59ECDE46 for ; Thu, 25 Oct 2018 14:21:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 69C3120883 for ; Thu, 25 Oct 2018 14:21:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="ftXH+y9E" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 69C3120883 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731351AbeJYWyB (ORCPT ); Thu, 25 Oct 2018 18:54:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:36798 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731324AbeJYWyA (ORCPT ); Thu, 25 Oct 2018 18:54:00 -0400 Received: from sasha-vm.mshome.net (unknown [167.98.65.38]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 85AFA20870; Thu, 25 Oct 2018 14:21:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1540477263; bh=V5XLa/ujWXTx9o5wX86QaxiVenlJpKNxuOvxoCJ3Dvs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ftXH+y9EKnwAYrlkNjCC0isLG83Y5+Zw4Joq0ePr3WligGlYWt1pTIgdBJwJ15O5g SEFtB5+TDFK7aSw09p9lEWuyw4BeUnhXNtFH3ZHCDrICK2xAjl3YExMwcJKco6UnQC PjLtYKVZMJH9amJc3NMToGRAhNIJtdSbtHuchLcU= From: Sasha Levin To: stable@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Peter Zijlstra , Alexander Potapenko , Arnaldo Carvalho de Melo , Arnaldo Carvalho de Melo , Eric Dumazet , Jiri Olsa , Kostya Serebryany , Linus Torvalds , Sasha Levin , Stephane Eranian , Thomas Gleixner , Vince Weaver , Ingo Molnar , Sasha Levin Subject: [PATCH AUTOSEL 3.18 84/98] perf: Fix PERF_EVENT_IOC_PERIOD deadlock Date: Thu, 25 Oct 2018 10:18:39 -0400 Message-Id: <20181025141853.214051-84-sashal@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181025141853.214051-1-sashal@kernel.org> References: <20181025141853.214051-1-sashal@kernel.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Peter Zijlstra [ Upstream commit 642c2d671ceff40e9453203ea0c66e991e11e249 ] Dmitry reported a fairly silly recursive lock deadlock for PERF_EVENT_IOC_PERIOD, fix this by explicitly doing the inactive part of __perf_event_period() instead of calling that function. Reported-by: Dmitry Vyukov Signed-off-by: Peter Zijlstra (Intel) Cc: Cc: Alexander Potapenko Cc: Arnaldo Carvalho de Melo Cc: Arnaldo Carvalho de Melo Cc: Eric Dumazet Cc: Jiri Olsa Cc: Kostya Serebryany Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Sasha Levin Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Fixes: c7999c6f3fed ("perf: Fix PERF_EVENT_IOC_PERIOD migration race") Link: http://lkml.kernel.org/r/20151130115615.GJ17308@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin --- kernel/events/core.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 1f08f691de59..7b2f9d432fe7 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3929,7 +3929,14 @@ static int perf_event_period(struct perf_event *event, u64 __user *arg) goto retry; } - __perf_event_period(&pe); + if (event->attr.freq) { + event->attr.sample_freq = value; + } else { + event->attr.sample_period = value; + event->hw.sample_period = value; + } + + local64_set(&event->hw.period_left, 0); raw_spin_unlock_irq(&ctx->lock); return 0; -- 2.17.1