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 E863CCD0408 for ; Mon, 5 Jan 2026 21:22:32 +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:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=jiFEeW5gN2osECrGX/NxhvJp4KMe2lAyJaSIXSOT3Og=; b=2i/KiKFbQ2QHp4oDGYD98GEvSP YvuBzUTIqGQAkHCfB7t/e7X/Y67HhpVt4wtfo1Vc2niHCpKOP1tMiaLSi/vYBfj4aAh+hprMIlZlE dP0qx+jlLi4U8NxIkphZCC8CU4EM+g/RgDv7KBUY+fBqXnFFbuiY1vylO9A/XjU9EZaG2W8KNvb6W 2GC1V43BiTiipANqFnnFHt0nWxyUD3JCUw21Gbq/bNqS7HG2qFWvsNl3dapsFFnkzUoURoSrdoVEd RdnLHewDKSdtQyXrgjUr3MBBZNxxBp6N4WelnKopixJHf+ATNkNhkL703ySdQUuktVsdthgGurDea NkmFsg5Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vcs1w-0000000C7OM-4C2o; Mon, 05 Jan 2026 21:22:25 +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 1vcs1r-0000000C7MS-1i2V for linux-arm-kernel@lists.infradead.org; Mon, 05 Jan 2026 21:22:23 +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 94C52339; Mon, 5 Jan 2026 13:22:09 -0800 (PST) Received: from localhost (e132581.arm.com [10.1.196.87]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id F3BDC3F694; Mon, 5 Jan 2026 13:22:15 -0800 (PST) Date: Mon, 5 Jan 2026 21:22:13 +0000 From: Leo Yan To: Puranjay Mohan Cc: Will Deacon , Mark Rutland , Rob Herring , Catalin Marinas , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Martin KaFai Lau , Eduard Zingerman , Kumar Kartikeya Dwivedi , Breno Leitao , linux-arm-kernel@lists.infradead.org, linux-perf-users@vger.kernel.org, kernel-team@meta.com Subject: Re: [RFC PATCH] perf/arm64: Add BRBE support for bpf_get_branch_snapshot() Message-ID: <20260105212213.GA336318@e132581.arm.com> References: <20260102214043.1410242-1-puranjay@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260105_132219_488934_1F3775BF X-CRM114-Status: GOOD ( 13.36 ) 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 Hi, On Fri, Jan 02, 2026 at 09:51:15PM +0000, Puranjay Mohan wrote: > Hi Catalin, Will, Mark, and Rob. > > I don't have access to BRBE enabled hardware and Qemu doesn't support > this as well therefore I just sent the compile tested version. > > Can you help me with testing this: > > The relevant bpf self test is: > > ./test_progs -t get_branch_snapshot > #132 get_branch_snapshot:SKIP > Summary: 1/0 PASSED, 1 SKIPPED, 0 FAILED > > skipped for my setup as it is not supported. eBPF selftest build is quite heavy (many dependencies), finally I built it cleanly. I did a test on FVP RevC, the test hit NULL pointer deference and kernel panic in armv8pmu_sched_task(). See https://termbin.com/peg4, the backtrace should can give you hints for the issue. Thanks, Leo P.s. some logs are duplicate, this might be caused by two cores both hit the NULL pointer issue ?