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Thu, 20 Jun 2024 06:37:43 -0400 X-MC-Unique: Fd1mNQJpP9-7xMIncwIweg-1 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 4A3F519560AA; Thu, 20 Jun 2024 10:37:40 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.45.226.26]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with SMTP id E32BA3000218; Thu, 20 Jun 2024 10:37:32 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Thu, 20 Jun 2024 12:36:08 +0200 (CEST) Date: Thu, 20 Jun 2024 12:36:00 +0200 From: Oleg Nesterov To: Tiezhu Yang Cc: Will Deacon , Mark Rutland , Catalin Marinas , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , linux-arm-kernel@lists.infradead.org, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] arm64: hw_breakpoint: Save privilege of access control via ptrace Message-ID: <20240620103600.GD30070@redhat.com> References: <20240618071010.11214-1-yangtiezhu@loongson.cn> <20240619151524.GB24240@redhat.com> <9cc6d314-2431-c1b5-3d46-63c0ac80ed4d@loongson.cn> <20240620090807.GC30070@redhat.com> <93d96e55-c180-444a-9b3f-f96db5f9e37d@loongson.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <93d96e55-c180-444a-9b3f-f96db5f9e37d@loongson.cn> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240620_033748_191444_28912324 X-CRM114-Status: GOOD ( 14.40 ) 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 Again, I can't really comment, I know almost nothing about perf, but On 06/20, Tiezhu Yang wrote: > > On 06/20/2024 05:08 PM, Oleg Nesterov wrote: > > > >But to me the very idea of arm64-specific and "kernel only" member in > >perf_event_attr looks a bit strange. > > I noticed that there is a similar arm64-specific change in > commit 09519ec3b19e ("perf: Add perf_event_attr::config3") but this is another thing even if I have no idea what .config3 means. If nothing else, what do you think, say, tools/perf can do with ->bp_priv? What should sys_perf_event_open() do if bp_priv != 0 comes from user space? Nevermind, please forget, I leave this to you and maintainers. Oleg.