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=-12.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLACK,USER_AGENT_GIT autolearn=unavailable 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 7E43FC433E3 for ; Mon, 24 Aug 2020 16:41:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4F09D20838 for ; Mon, 24 Aug 2020 16:41:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598287307; bh=KlWH/GVv4Oic7hSyZEI1sR8GB+jaHJHJCd6PjbbY9RE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=joTsoZkfFwfv19O3PmwFJEdI9R6CghI7+ahxjeDat3XwnSDZGokNp8aTZtWlrBY4c 7z6/zd0NXUrJMjWrdk4VaZv78nirF+HL70x75mOgK+02gPlT40/PNjpUteJV937oVJ JOjjpsDjnGftY5SCbyDUXPW497vBnJ9cFh/K9tGc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728584AbgHXQln (ORCPT ); Mon, 24 Aug 2020 12:41:43 -0400 Received: from mail.kernel.org ([198.145.29.99]:48074 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728631AbgHXQjw (ORCPT ); Mon, 24 Aug 2020 12:39:52 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (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 E5AB422CB1; Mon, 24 Aug 2020 16:39:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598287191; bh=KlWH/GVv4Oic7hSyZEI1sR8GB+jaHJHJCd6PjbbY9RE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0Zfv3sFSCEWZ42Vl64tpBPTHUrSjsqSAzmmTxECS7MIo0We8ikIaPyB908CfWKAqG 0SGIHSMoRbnh6YC1z6R/ZBpDn1ER2brd0oeuW4bTyi0zUx2i8B5Qr51NHXTMOpmOup bCr1Wf83SbxmizC2JE4/Gvcyw7F0M/sKpUOSDkvQ= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Athira Rajeev , Alexey Kardashevskiy , Michael Ellerman , Sasha Levin , linuxppc-dev@lists.ozlabs.org Subject: [PATCH AUTOSEL 4.4 6/6] powerpc/perf: Fix soft lockups due to missed interrupt accounting Date: Mon, 24 Aug 2020 12:39:43 -0400 Message-Id: <20200824163943.607406-6-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200824163943.607406-1-sashal@kernel.org> References: <20200824163943.607406-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Athira Rajeev [ Upstream commit 17899eaf88d689529b866371344c8f269ba79b5f ] Performance monitor interrupt handler checks if any counter has overflown and calls record_and_restart() in core-book3s which invokes perf_event_overflow() to record the sample information. Apart from creating sample, perf_event_overflow() also does the interrupt and period checks via perf_event_account_interrupt(). Currently we record information only if the SIAR (Sampled Instruction Address Register) valid bit is set (using siar_valid() check) and hence the interrupt check. But it is possible that we do sampling for some events that are not generating valid SIAR, and hence there is no chance to disable the event if interrupts are more than max_samples_per_tick. This leads to soft lockup. Fix this by adding perf_event_account_interrupt() in the invalid SIAR code path for a sampling event. ie if SIAR is invalid, just do interrupt check and don't record the sample information. Reported-by: Alexey Kardashevskiy Signed-off-by: Athira Rajeev Tested-by: Alexey Kardashevskiy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/1596717992-7321-1-git-send-email-atrajeev@linux.vnet.ibm.com Signed-off-by: Sasha Levin --- arch/powerpc/perf/core-book3s.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c index 30e2e8efbe6b7..aab13558e9700 100644 --- a/arch/powerpc/perf/core-book3s.c +++ b/arch/powerpc/perf/core-book3s.c @@ -2040,6 +2040,10 @@ static void record_and_restart(struct perf_event *event, unsigned long val, if (perf_event_overflow(event, &data, regs)) power_pmu_stop(event, 0); + } else if (period) { + /* Account for interrupt in case of invalid SIAR */ + if (perf_event_account_interrupt(event)) + power_pmu_stop(event, 0); } } -- 2.25.1