From patchwork Thu Feb 22 17:07:49 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Anderson X-Patchwork-Id: 13567615 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 82F17C48BF8 for ; Thu, 22 Feb 2024 17:08:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Bw9PrZwY8HJSxH4t33zDSB+6htoZ0qGg/Kc/YPWg8T0=; b=mWJBd5z8J544W6 e1wkc3YmShQqCtFWsM2pGCHdKGhusxM/SaY6/8aPC1DndQTy1AStyHtZ/58ZwRKsTGEhbZzumWjRx x+kgYdINWs1cJ07Kz4XnXMgNlCAZT41JEys1olZjOxMXUel+Gk18yxObbIdStXkhfWNfemqCgP6sR BdT20VibNEoEbUSOukdx3JvzYrOuJ2PXcohOPLyXZGvWAilJUdeCicgfScWIBahpNGAOd53Gof/dU fF6c355ixT57mR94r6c6c7uYSveLn0zEXQpagBL1TZtw0sn0Sr3SzNA2lAbr/4WTjn8suRlVr6Pat UONz0ON5pShE+bE1VP1w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rdCYY-00000005j0E-2FSI; Thu, 22 Feb 2024 17:08:22 +0000 Received: from out-184.mta1.migadu.com ([95.215.58.184]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rdCYO-00000005iwZ-1SG3 for linux-arm-kernel@lists.infradead.org; Thu, 22 Feb 2024 17:08:20 +0000 X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1708621684; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=A9cw43y7Ag2nW/FmjThiF7L/nsZOb2YeI0T4JXqjgN0=; b=rzeeEd49VE0/ALeGOGSSbg143s8OTwaFAvrxCY6yGJTNFwwjFnEicT6dia7ttVnRyvmbnK HyDFt3Yl46a0RnAXHRXJg/oBUW/egxgGR1825W80HSdBCnN6zALR51w2yk6tin+AfQdKwQ QIFIm5ehJbZHhRkiGNuQTCV3GBhhgdo= From: Sean Anderson To: "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , netdev@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org, Claudiu Manoil , Vladimir Oltean , linuxppc-dev@lists.ozlabs.org, Steffen Trumtrar , linux-kernel@vger.kernel.org, Camelia Groza , Roy Pledge , Scott Wood , Li Yang , Sean Anderson , stable@vger.kernel.org Subject: [RESEND2 PATCH net v4 2/2] soc: fsl: qbman: Use raw spinlock for cgr_lock Date: Thu, 22 Feb 2024 12:07:49 -0500 Message-Id: <20240222170749.2607485-2-sean.anderson@linux.dev> In-Reply-To: <20240222170749.2607485-1-sean.anderson@linux.dev> References: <20240222170749.2607485-1-sean.anderson@linux.dev> MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240222_090819_018412_9ACCA598 X-CRM114-Status: GOOD ( 16.04 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org cgr_lock may be locked with interrupts already disabled by smp_call_function_single. As such, we must use a raw spinlock to avoid problems on PREEMPT_RT kernels. Although this bug has existed for a while, it was not apparent until commit ef2a8d5478b9 ("net: dpaa: Adjust queue depth on rate change") which invokes smp_call_function_single via qman_update_cgr_safe every time a link goes up or down. Fixes: 96f413f47677 ("soc/fsl/qbman: fix issue in qman_delete_cgr_safe()") CC: stable@vger.kernel.org Reported-by: Vladimir Oltean Closes: https://lore.kernel.org/all/20230323153935.nofnjucqjqnz34ej@skbuf/ Reported-by: Steffen Trumtrar Closes: https://lore.kernel.org/linux-arm-kernel/87wmsyvclu.fsf@pengutronix.de/ Signed-off-by: Sean Anderson Reviewed-by: Camelia Groza Tested-by: Vladimir Oltean --- Changes in v4: - Add a note about how raw spinlocks aren't quite right Changes in v3: - Change blamed commit to something more appropriate drivers/soc/fsl/qbman/qman.c | 25 ++++++++++++++----------- 1 file changed, 14 insertions(+), 11 deletions(-) diff --git a/drivers/soc/fsl/qbman/qman.c b/drivers/soc/fsl/qbman/qman.c index 1bf1f1ea67f0..7e9074519ad2 100644 --- a/drivers/soc/fsl/qbman/qman.c +++ b/drivers/soc/fsl/qbman/qman.c @@ -991,7 +991,7 @@ struct qman_portal { /* linked-list of CSCN handlers. */ struct list_head cgr_cbs; /* list lock */ - spinlock_t cgr_lock; + raw_spinlock_t cgr_lock; struct work_struct congestion_work; struct work_struct mr_work; char irqname[MAX_IRQNAME]; @@ -1281,7 +1281,7 @@ static int qman_create_portal(struct qman_portal *portal, /* if the given mask is NULL, assume all CGRs can be seen */ qman_cgrs_fill(&portal->cgrs[0]); INIT_LIST_HEAD(&portal->cgr_cbs); - spin_lock_init(&portal->cgr_lock); + raw_spin_lock_init(&portal->cgr_lock); INIT_WORK(&portal->congestion_work, qm_congestion_task); INIT_WORK(&portal->mr_work, qm_mr_process_task); portal->bits = 0; @@ -1456,11 +1456,14 @@ static void qm_congestion_task(struct work_struct *work) union qm_mc_result *mcr; struct qman_cgr *cgr; - spin_lock_irq(&p->cgr_lock); + /* + * FIXME: QM_MCR_TIMEOUT is 10ms, which is too long for a raw spinlock! + */ + raw_spin_lock_irq(&p->cgr_lock); qm_mc_start(&p->p); qm_mc_commit(&p->p, QM_MCC_VERB_QUERYCONGESTION); if (!qm_mc_result_timeout(&p->p, &mcr)) { - spin_unlock_irq(&p->cgr_lock); + raw_spin_unlock_irq(&p->cgr_lock); dev_crit(p->config->dev, "QUERYCONGESTION timeout\n"); qman_p_irqsource_add(p, QM_PIRQ_CSCI); return; @@ -1476,7 +1479,7 @@ static void qm_congestion_task(struct work_struct *work) list_for_each_entry(cgr, &p->cgr_cbs, node) if (cgr->cb && qman_cgrs_get(&c, cgr->cgrid)) cgr->cb(p, cgr, qman_cgrs_get(&rr, cgr->cgrid)); - spin_unlock_irq(&p->cgr_lock); + raw_spin_unlock_irq(&p->cgr_lock); qman_p_irqsource_add(p, QM_PIRQ_CSCI); } @@ -2440,7 +2443,7 @@ int qman_create_cgr(struct qman_cgr *cgr, u32 flags, preempt_enable(); cgr->chan = p->config->channel; - spin_lock_irq(&p->cgr_lock); + raw_spin_lock_irq(&p->cgr_lock); if (opts) { struct qm_mcc_initcgr local_opts = *opts; @@ -2477,7 +2480,7 @@ int qman_create_cgr(struct qman_cgr *cgr, u32 flags, qman_cgrs_get(&p->cgrs[1], cgr->cgrid)) cgr->cb(p, cgr, 1); out: - spin_unlock_irq(&p->cgr_lock); + raw_spin_unlock_irq(&p->cgr_lock); put_affine_portal(); return ret; } @@ -2512,7 +2515,7 @@ int qman_delete_cgr(struct qman_cgr *cgr) return -EINVAL; memset(&local_opts, 0, sizeof(struct qm_mcc_initcgr)); - spin_lock_irqsave(&p->cgr_lock, irqflags); + raw_spin_lock_irqsave(&p->cgr_lock, irqflags); list_del(&cgr->node); /* * If there are no other CGR objects for this CGRID in the list, @@ -2537,7 +2540,7 @@ int qman_delete_cgr(struct qman_cgr *cgr) /* add back to the list */ list_add(&cgr->node, &p->cgr_cbs); release_lock: - spin_unlock_irqrestore(&p->cgr_lock, irqflags); + raw_spin_unlock_irqrestore(&p->cgr_lock, irqflags); put_affine_portal(); return ret; } @@ -2577,9 +2580,9 @@ static int qman_update_cgr(struct qman_cgr *cgr, struct qm_mcc_initcgr *opts) if (!p) return -EINVAL; - spin_lock_irqsave(&p->cgr_lock, irqflags); + raw_spin_lock_irqsave(&p->cgr_lock, irqflags); ret = qm_modify_cgr(cgr, 0, opts); - spin_unlock_irqrestore(&p->cgr_lock, irqflags); + raw_spin_unlock_irqrestore(&p->cgr_lock, irqflags); put_affine_portal(); return ret; }