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 8A8D6CA0FE7 for ; Tue, 26 Aug 2025 14:53:23 +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:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=WhKz8FrFft/u4hm9OW/HZu1vjQWYJCf/2kiwLIrceOw=; b=Jj6PIzOaSLD7qN Q+4pNcTpKFlkZp7Wc93mgWQR44lJPdH1/eIUUCBeoc6FWLH3F1tn9tr9whSovhuhyy1pLCU48uGBV XKJgGT4GcyxaSqrLjRHTL0r2+P1oer4kVpAeuk6VMf8q4k1ywS4MnIuWpaVBqmjfC67F5P3GrFMCC 4a7bY3Obo90cHlz87vTU0Xy9EEWjH2hPJOACPZaCXTYo7okAfnbYfmXJ6NwQO/JzbzN5WBHBoc1tz i3PC8YuHwipfKVXS9zgqMC+ijqiB6O9coSIDZOaa/0EY7PXc9iAbhB86F1ML/yGxA7oMJMgZTjuc0 kvbfQHAwUr3W1or6A8pw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uqv30-0000000CKvq-03oD; Tue, 26 Aug 2025 14:53:18 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uqtZF-0000000C4ck-3FYB; Tue, 26 Aug 2025 13:18:31 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B0DEB1A25; Tue, 26 Aug 2025 06:18:20 -0700 (PDT) Received: from J2N7QTR9R3 (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E10B23F63F; Tue, 26 Aug 2025 06:18:22 -0700 (PDT) Date: Tue, 26 Aug 2025 14:18:16 +0100 From: Mark Rutland To: Robin Murphy Cc: peterz@infradead.org, mingo@redhat.com, will@kernel.org, acme@kernel.org, namhyung@kernel.org, alexander.shishkin@linux.intel.com, jolsa@kernel.org, irogers@google.com, adrian.hunter@intel.com, kan.liang@linux.intel.com, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, linux-alpha@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, imx@lists.linux.dev, linux-csky@vger.kernel.org, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-pm@vger.kernel.org, linux-rockchip@lists.infradead.org, dmaengine@vger.kernel.org, linux-fpga@vger.kernel.org, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org, coresight@lists.linaro.org, iommu@lists.linux.dev, linux-amlogic@lists.infradead.org, linux-cxl@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-riscv@lists.infradead.org Subject: Re: [PATCH 02/19] perf/hisilicon: Fix group validation Message-ID: References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250826_061829_940885_FC68B2D6 X-CRM114-Status: GOOD ( 23.95 ) X-BeenThere: linux-rockchip@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Upstream kernel work for Rockchip platforms List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-rockchip" Errors-To: linux-rockchip-bounces+linux-rockchip=archiver.kernel.org@lists.infradead.org On Tue, Aug 26, 2025 at 12:15:23PM +0100, Mark Rutland wrote: > On Wed, Aug 13, 2025 at 06:00:54PM +0100, Robin Murphy wrote: > > The group validation logic shared by the HiSilicon HNS3/PCIe drivers is > > a bit off, in that given a software group leader, it will consider that > > event *in place of* the actual new event being opened. At worst this > > could theoretically allow an unschedulable group if the software event > > config happens to look like one of the hardware siblings. > > > > The uncore framework avoids that particular issue, > > What is "the uncore framework"? I'm not sure exactly what you're > referring to, nor how that composes with the problem described above. > > > but all 3 also share the common issue of not preventing racy access to > > the sibling list, > > Can you please elaborate on this racy access to the silbing list? I'm > not sure exactly what you're referring to. Ah, I think you're referring to the issue in: https://lore.kernel.org/linux-arm-kernel/Zg0l642PgQ7T3a8Z@FVFF77S0Q05N/ ... where when creatign a new event which is its own group leader, lockdep_assert_event_ctx(event) fires in for_each_sibling_event(), because the new event's context isn't locked... > > diff --git a/drivers/perf/hisilicon/hisi_uncore_pmu.c b/drivers/perf/hisilicon/hisi_uncore_pmu.c > > index a449651f79c9..3c531b36cf25 100644 > > --- a/drivers/perf/hisilicon/hisi_uncore_pmu.c > > +++ b/drivers/perf/hisilicon/hisi_uncore_pmu.c > > @@ -101,26 +101,17 @@ static bool hisi_validate_event_group(struct perf_event *event) > > /* Include count for the event */ > > int counters = 1; > > > > - if (!is_software_event(leader)) { > > - /* > > - * We must NOT create groups containing mixed PMUs, although > > - * software events are acceptable > > - */ > > - if (leader->pmu != event->pmu) > > - return false; > > + if (leader == event) > > + return true; ... and hence bailing out here avoids that? It's not strictly "racy access to the sibling list", becuase there's nothing else accessing the list; it's just that this is the simplest way to appease lockdep while avoiding false negatives. It'd probably be better to say something like "the common issue of calling for_each_sibling_event() when initialising a new group leader", and maybe to spell that out a bit. Mark. _______________________________________________ Linux-rockchip mailing list Linux-rockchip@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-rockchip