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 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 F1AB8C02181 for ; Fri, 24 Jan 2025 06:53:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=UUWDcgHyAFM18RO3R6oc8J3erVbUv0Ng/r++00YFCrU=; b=jNcxANegO9YclDujdodv7eDa1t GBwgSLU66ZDAQRhlIfRAQ2aAUxJreXoUQwOdfV1VuJFTMQwmpX0f7P2e/c4BmYcke/6wvImIWwMa6 e7n9kqpp+8HSGjR3BW+NXVcWo/XpDteBhdDJyJxZa76kdUIow9gBzBQeQbjKxTF4Nl/akOCT5D1Is fWlNBvuJZjWXXFlTZaEmmkVIW2eBQTEaMdfBvGCrZIZTAB9dYo+GmN3GG/KPFOwEUBJnnvzLe0VpP GV3Ee+cT5DZE1HP5K4G6IuFAdiZHa83vnczDXtwJ2WPT478CDupBJqoq0ahA7exOD7kkv4dm6JGjP PnLhsZMw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tbDZJ-0000000E3gL-3kHY; Fri, 24 Jan 2025 06:53:29 +0000 Received: from out30-97.freemail.mail.aliyun.com ([115.124.30.97]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tbDUb-0000000E2MT-3KtB for linux-arm-kernel@lists.infradead.org; Fri, 24 Jan 2025 06:48:40 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1737701313; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=UUWDcgHyAFM18RO3R6oc8J3erVbUv0Ng/r++00YFCrU=; b=KXgHq9bVyBkZcDMAsC+DnwjmU/6qkpkI/HlJp9V9jNzKwwWEMZ3b57r1Ckm0tDXf37yiuV6wki3sFCZbDP2IPpT6/5FQDKeK8FBmyYcrKW3EOji92QcvWuNNUCXfbjyQKkpO0c5pXCxbEI32qX1mIbBqrJXIC0Dbw1Xp1tzSv/A= Received: from 30.246.161.230(mailfrom:xueshuai@linux.alibaba.com fp:SMTPD_---0WODip5B_1737701310 cluster:ay36) by smtp.aliyun-inc.com; Fri, 24 Jan 2025 14:48:31 +0800 Message-ID: <31e00081-8695-4ca6-a1ef-af5a007a7565@linux.alibaba.com> Date: Fri, 24 Jan 2025 14:48:30 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [External] Re: [PATCH] perf/dwc_pcie: fix duplicate pci_dev devices To: yunhui cui Cc: renyu.zj@linux.alibaba.com, will@kernel.org, mark.rutland@arm.com, linux-arm-kernel@lists.infradead.org, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org References: <20250123074830.90923-1-cuiyunhui@bytedance.com> <344c53cd-d856-4c03-9deb-743b65acd8aa@linux.alibaba.com> From: Shuai Xue In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250123_224838_594074_A6569636 X-CRM114-Status: GOOD ( 16.98 ) 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 在 2025/1/24 10:56, yunhui cui 写道: > Hi Shuai, > > On Thu, Jan 23, 2025 at 5:50 PM Shuai Xue wrote: >> >> >> >> 在 2025/1/23 15:48, Yunhui Cui 写道: >>> During platform_device_register, wrongly using struct device >>> pci_dev as platform_data caused a kmemdup copy of pci_dev. Worse >>> still, accessing the duplicated device leads to list corruption as its >>> mutex content (e.g., list, magic) remains the same as the original. >>> >>> Signed-off-by: Yunhui Cui >>> --- >>> drivers/perf/dwc_pcie_pmu.c | 25 ++++++++++++++++++------- >>> 1 file changed, 18 insertions(+), 7 deletions(-) >>> >>> diff --git a/drivers/perf/dwc_pcie_pmu.c b/drivers/perf/dwc_pcie_pmu.c >>> index cccecae9823f..8b208f287a1f 100644 >>> --- a/drivers/perf/dwc_pcie_pmu.c >>> +++ b/drivers/perf/dwc_pcie_pmu.c >>> @@ -565,9 +565,7 @@ static int dwc_pcie_register_dev(struct pci_dev *pdev) >>> u32 sbdf; >>> >>> sbdf = (pci_domain_nr(pdev->bus) << 16) | PCI_DEVID(pdev->bus->number, pdev->devfn); >>> - plat_dev = platform_device_register_data(NULL, "dwc_pcie_pmu", sbdf, >>> - pdev, sizeof(*pdev)); >>> - >>> + plat_dev = platform_device_register_simple("platform_dwc_pcie", sbdf, NULL, 0); >>> if (IS_ERR(plat_dev)) >>> return PTR_ERR(plat_dev); >>> >>> @@ -614,19 +612,32 @@ static struct notifier_block dwc_pcie_pmu_nb = { >>> >>> static int dwc_pcie_pmu_probe(struct platform_device *plat_dev) >>> { >>> - struct pci_dev *pdev = plat_dev->dev.platform_data; >>> + struct pci_dev *pdev = NULL; >>> struct dwc_pcie_pmu *pcie_pmu; >>> + bool found = false; >>> char *name; >>> u32 sbdf; >>> u16 vsec; >>> int ret; >>> >>> + for_each_pci_dev(pdev) { >>> + sbdf = (pci_domain_nr(pdev->bus) << 16) | PCI_DEVID(pdev->bus->number, pdev->devfn); >>> + if (sbdf == plat_dev->id) { >>> + found = true; >>> + break; >>> + } >>> + } >>> + if (!found) { >>> + pr_err("The plat_dev->id does not match the sbdf"); >>> + return -ENODEV; >>> + } >>> + >> >> How about using pci_get_domain_bus_and_slot() to find pci_dev? > It's not necessary. pci_get_domain_bus_and_slot also invokes > for_each_pci_dev, and it further requires splitting the sbdf. Compose sbdf from domain, bus number, and devfn is almost essentially corresponding opposite operation. And I think we should grab a reference count of pdev and handle it properly. Personally speaking, I prefer pci_get_domain_bus_and_slot() because it is simple and robust. > >> >>> vsec = dwc_pcie_des_cap(pdev); >>> if (!vsec) >>> return -ENODEV; >>> >>> sbdf = plat_dev->id; >>> - name = devm_kasprintf(&plat_dev->dev, GFP_KERNEL, "dwc_rootport_%x", sbdf); >>> + name = devm_kasprintf(&plat_dev->dev, GFP_KERNEL, "dwc_rootport_%d_pmu", sbdf); >> >> A new name will break previous user tools. > This name isn't suitable. It can't clearly show which is the PMU > device. Userspace tools don't have binding relationships, like perf. > Tools must traverse PMU devices before use. The device is under /sys/bus/event_source/ which indates it is PMU device. As far as I know, most of PMU devices do not endup with a '_pmu' prefix. Thanks. Shuai