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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6F93BC433EF for ; Mon, 31 Jan 2022 11:35:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1376623AbiAaLfR (ORCPT ); Mon, 31 Jan 2022 06:35:17 -0500 Received: from dfw.source.kernel.org ([139.178.84.217]:56242 "EHLO dfw.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1377970AbiAaLXg (ORCPT ); Mon, 31 Jan 2022 06:23:36 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 91F3561267; Mon, 31 Jan 2022 11:23:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6DE6FC340E8; Mon, 31 Jan 2022 11:23:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643628215; bh=GjGO6KS8Wz7i9WHvfILtYVTbWhOHZcSOqBUaV99E+jw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=THmomt2b3LcbF9pgPBcYr1Y7AxxwDKP7vckN8/Le7+xrKXiwtDxyXO5FnPV98PJsE mFlQmdJuThUlXnz46wKV5y1y2hX4GuG1nSse4bEk9x6fFbWy8hG4l6O4x6hVmgdZ7A CGRkyMBCrxyTNME9kNMijYN5KXoqQtTmp6GtAqew= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sachin Sant , Athira Rajeev , Nicholas Piggin , Michael Ellerman , Sasha Levin Subject: [PATCH 5.16 160/200] powerpc/perf: Fix power_pmu_disable to call clear_pmi_irq_pending only if PMI is pending Date: Mon, 31 Jan 2022 11:57:03 +0100 Message-Id: <20220131105238.935259652@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220131105233.561926043@linuxfoundation.org> References: <20220131105233.561926043@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Athira Rajeev [ Upstream commit fb6433b48a178d4672cb26632454ee0b21056eaa ] Running selftest with CONFIG_PPC_IRQ_SOFT_MASK_DEBUG enabled in kernel triggered below warning: [ 172.851380] ------------[ cut here ]------------ [ 172.851391] WARNING: CPU: 8 PID: 2901 at arch/powerpc/include/asm/hw_irq.h:246 power_pmu_disable+0x270/0x280 [ 172.851402] Modules linked in: dm_mod bonding nft_ct nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ip_set nf_tables rfkill nfnetlink sunrpc xfs libcrc32c pseries_rng xts vmx_crypto uio_pdrv_genirq uio sch_fq_codel ip_tables ext4 mbcache jbd2 sd_mod t10_pi sg ibmvscsi ibmveth scsi_transport_srp fuse [ 172.851442] CPU: 8 PID: 2901 Comm: lost_exception_ Not tainted 5.16.0-rc5-03218-g798527287598 #2 [ 172.851451] NIP: c00000000013d600 LR: c00000000013d5a4 CTR: c00000000013b180 [ 172.851458] REGS: c000000017687860 TRAP: 0700 Not tainted (5.16.0-rc5-03218-g798527287598) [ 172.851465] MSR: 8000000000029033 CR: 48004884 XER: 20040000 [ 172.851482] CFAR: c00000000013d5b4 IRQMASK: 1 [ 172.851482] GPR00: c00000000013d5a4 c000000017687b00 c000000002a10600 0000000000000004 [ 172.851482] GPR04: 0000000082004000 c0000008ba08f0a8 0000000000000000 00000008b7ed0000 [ 172.851482] GPR08: 00000000446194f6 0000000000008000 c00000000013b118 c000000000d58e68 [ 172.851482] GPR12: c00000000013d390 c00000001ec54a80 0000000000000000 0000000000000000 [ 172.851482] GPR16: 0000000000000000 0000000000000000 c000000015d5c708 c0000000025396d0 [ 172.851482] GPR20: 0000000000000000 0000000000000000 c00000000a3bbf40 0000000000000003 [ 172.851482] GPR24: 0000000000000000 c0000008ba097400 c0000000161e0d00 c00000000a3bb600 [ 172.851482] GPR28: c000000015d5c700 0000000000000001 0000000082384090 c0000008ba0020d8 [ 172.851549] NIP [c00000000013d600] power_pmu_disable+0x270/0x280 [ 172.851557] LR [c00000000013d5a4] power_pmu_disable+0x214/0x280 [ 172.851565] Call Trace: [ 172.851568] [c000000017687b00] [c00000000013d5a4] power_pmu_disable+0x214/0x280 (unreliable) [ 172.851579] [c000000017687b40] [c0000000003403ac] perf_pmu_disable+0x4c/0x60 [ 172.851588] [c000000017687b60] [c0000000003445e4] __perf_event_task_sched_out+0x1d4/0x660 [ 172.851596] [c000000017687c50] [c000000000d1175c] __schedule+0xbcc/0x12a0 [ 172.851602] [c000000017687d60] [c000000000d11ea8] schedule+0x78/0x140 [ 172.851608] [c000000017687d90] [c0000000001a8080] sys_sched_yield+0x20/0x40 [ 172.851615] [c000000017687db0] [c0000000000334dc] system_call_exception+0x18c/0x380 [ 172.851622] [c000000017687e10] [c00000000000c74c] system_call_common+0xec/0x268 The warning indicates that MSR_EE being set(interrupt enabled) when there was an overflown PMC detected. This could happen in power_pmu_disable since it runs under interrupt soft disable condition ( local_irq_save ) and not with interrupts hard disabled. commit 2c9ac51b850d ("powerpc/perf: Fix PMU callbacks to clear pending PMI before resetting an overflown PMC") intended to clear PMI pending bit in Paca when disabling the PMU. It could happen that PMC gets overflown while code is in power_pmu_disable callback function. Hence add a check to see if PMI pending bit is set in Paca before clearing it via clear_pmi_pending. Fixes: 2c9ac51b850d ("powerpc/perf: Fix PMU callbacks to clear pending PMI before resetting an overflown PMC") Reported-by: Sachin Sant Signed-off-by: Athira Rajeev Tested-by: Sachin Sant Reviewed-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220122033429.25395-1-atrajeev@linux.vnet.ibm.com Signed-off-by: Sasha Levin --- arch/powerpc/perf/core-book3s.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c index bef6b1abce702..e78de70509472 100644 --- a/arch/powerpc/perf/core-book3s.c +++ b/arch/powerpc/perf/core-book3s.c @@ -1326,9 +1326,20 @@ static void power_pmu_disable(struct pmu *pmu) * Otherwise provide a warning if there is PMI pending, but * no counter is found overflown. */ - if (any_pmc_overflown(cpuhw)) - clear_pmi_irq_pending(); - else + if (any_pmc_overflown(cpuhw)) { + /* + * Since power_pmu_disable runs under local_irq_save, it + * could happen that code hits a PMC overflow without PMI + * pending in paca. Hence only clear PMI pending if it was + * set. + * + * If a PMI is pending, then MSR[EE] must be disabled (because + * the masked PMI handler disabling EE). So it is safe to + * call clear_pmi_irq_pending(). + */ + if (pmi_irq_pending()) + clear_pmi_irq_pending(); + } else WARN_ON(pmi_irq_pending()); val = mmcra = cpuhw->mmcr.mmcra; -- 2.34.1