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=-13.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,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 1C33CC4727C for ; Tue, 29 Sep 2020 20:31:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A207F2076B for ; Tue, 29 Sep 2020 20:31:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="FgEC/9Tj" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727761AbgI2UbH (ORCPT ); Tue, 29 Sep 2020 16:31:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36472 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727740AbgI2UbH (ORCPT ); Tue, 29 Sep 2020 16:31:07 -0400 Received: from mail-pj1-x1041.google.com (mail-pj1-x1041.google.com [IPv6:2607:f8b0:4864:20::1041]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4292BC061755 for ; Tue, 29 Sep 2020 13:31:06 -0700 (PDT) Received: by mail-pj1-x1041.google.com with SMTP id b17so3351343pji.1 for ; Tue, 29 Sep 2020 13:31:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=w6Gs5CgGrT7/dE/0i0Kz33QzSpxebvhL70Kc9W54Bfk=; b=FgEC/9TjFwz3LPuu1b3e38wqyfYZXVCqBvGpZ+E6u8Kdp5LeC4QfJscyElLXVW4tfr vRBfHkvctRKVaQL7QyBu8BrHU5iDWdwmJ8MaGj4PMgeSw2W1dshGhEBEvFtkHMk9TuHg OwbSbd7mZGtr2aB+KZOl8Dyxb+aaZjO5Gzh90= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=w6Gs5CgGrT7/dE/0i0Kz33QzSpxebvhL70Kc9W54Bfk=; b=cT2i4rEzEnrxt1M19AnpeOcIsomLuhtWKQe9okNA9GWkXntskngAI7/U/z9PMeiNlb /Hs9yN6jXQ2Jq5Fe1D/KXt0eZGBltn1lfoaxgR3k65ZGcqA+vO84NUgu06DUnonvKaPd yH8izcX9LJzXK2TLU0boBpPdmXGVjMos/Il0VbT5zZpUcueVROseeOXO0EIk1/u0wVLB eq8OLRdK+TjMSsfINiSEdUhRxmHc16NMhg7YzpbpKZ9hqdooTEJnWZwYrgSgPuvXpqK0 weLQPRb/GeWyolIMGQvLdtPMxbl6Sye2YyGpfk3x4T344StHkwraRKqfd4gcS/Q2JOGB m0NQ== X-Gm-Message-State: AOAM532B/s1D6WIPrlvAWLcktHV0zpn8qR7Hj2VhpXN+uxtxwvRKXkjS hX3fEtoguyYXNA/ddvB/Cdr7fw== X-Google-Smtp-Source: ABdhPJwmrwBwUiVGBgxlOcHDg1VpFJuJtHBMscZT15BqLh6qfbkVr+93YRjl0YskxIVEgWtawk4JCw== X-Received: by 2002:a17:90a:fb53:: with SMTP id iq19mr5465867pjb.122.1601411465785; Tue, 29 Sep 2020 13:31:05 -0700 (PDT) Received: from evgreen-glaptop.cheshire.ch ([2601:646:c780:1404:a2ce:c8ff:fec4:54a3]) by smtp.gmail.com with ESMTPSA id j9sm5997167pfc.175.2020.09.29.13.31.04 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 29 Sep 2020 13:31:05 -0700 (PDT) From: Evan Green To: Bjorn Andersson Cc: Markus Elfring , Evan Green , Andy Gross , linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [RESEND PATCH] soc: qcom: smp2p: Safely acquire spinlock without IRQs Date: Tue, 29 Sep 2020 13:30:57 -0700 Message-Id: <20200929133040.RESEND.1.Ideabf6dcdfc577cf39ce3d95b0e4aa1ac8b38f0c@changeid> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org smp2p_update_bits() should disable interrupts when it acquires its spinlock. This is important because without the _irqsave, a priority inversion can occur. This function is called both with interrupts enabled in qcom_q6v5_request_stop(), and with interrupts disabled in ipa_smp2p_panic_notifier(). IRQ handling of spinlocks should be consistent to avoid the panic notifier deadlocking because it's sitting on the thread that's already got the lock via _request_stop(). Found via lockdep. Fixes: 50e99641413e7 ("soc: qcom: smp2p: Qualcomm Shared Memory Point to Point") Signed-off-by: Evan Green --- drivers/soc/qcom/smp2p.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/soc/qcom/smp2p.c b/drivers/soc/qcom/smp2p.c index 07183d731d747..a9709aae54abb 100644 --- a/drivers/soc/qcom/smp2p.c +++ b/drivers/soc/qcom/smp2p.c @@ -318,15 +318,16 @@ static int qcom_smp2p_inbound_entry(struct qcom_smp2p *smp2p, static int smp2p_update_bits(void *data, u32 mask, u32 value) { struct smp2p_entry *entry = data; + unsigned long flags; u32 orig; u32 val; - spin_lock(&entry->lock); + spin_lock_irqsave(&entry->lock, flags); val = orig = readl(entry->value); val &= ~mask; val |= value; writel(val, entry->value); - spin_unlock(&entry->lock); + spin_unlock_irqrestore(&entry->lock, flags); if (val != orig) qcom_smp2p_kick(entry->smp2p); -- 2.26.2