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=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 DC959C433E1 for ; Mon, 24 Aug 2020 16:44:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A5ECB2067C for ; Mon, 24 Aug 2020 16:44:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598287443; bh=y1xrZB73UBLkKpH9sshs4QQ2EYIUcbA/kyqtn27aCng=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=OS4KxxVtnPGuaZX8dNsBNs4vvzmcBxs52WO+SwLgu/rqlgJl2I5oAiEpYvTSRG1FF 7GQsVPIeJjsSf9z8ysGZM1mNzggVr0o5z+UGkrAiAkQf8ju8zmqeGyh4CFTv2TK0Dh 6qCB7Q7dgsl3kPf73UqmZN7FLUYNg7EY52eCG3EM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728647AbgHXQoB (ORCPT ); Mon, 24 Aug 2020 12:44:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:47588 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728597AbgHXQjh (ORCPT ); Mon, 24 Aug 2020 12:39:37 -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 8639922D07; Mon, 24 Aug 2020 16:39:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598287170; bh=y1xrZB73UBLkKpH9sshs4QQ2EYIUcbA/kyqtn27aCng=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kGMbmlONW7yRvcLW1FMbB8Nl+AqXLmgyDPSX9j06xaUQEfjZhTb//FIj3KGcqARdT 3Vu+JByCfvO2fEGUt3E/njKBWSajaNRC4jg6Y2wm5jKZenZZRqGJ+7jBL/M+xEZ6qL sTdJ6R2hYnJy0xwfypzpof6HFBAXsansQt7jl1ns= 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 4.14 11/11] powerpc/perf: Fix soft lockups due to missed interrupt accounting Date: Mon, 24 Aug 2020 12:39:14 -0400 Message-Id: <20200824163914.607152-11-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200824163914.607152-1-sashal@kernel.org> References: <20200824163914.607152-1-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 3188040022c4f..78f75e48dfe7f 100644 --- a/arch/powerpc/perf/core-book3s.c +++ b/arch/powerpc/perf/core-book3s.c @@ -2096,6 +2096,10 @@ 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