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Mon, 9 Nov 2026 11:10:12 +0000 (UTC) Received: from onestero-thinkpadp1gen7.tpbc.csb (headnet04.pony-001.prod.iad2.dc.redhat.com [10.2.32.116]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with SMTP id 7CF551800480; Mon, 9 Nov 2026 11:10:09 +0000 (UTC) Received: by onestero-thinkpadp1gen7.tpbc.csb (nbSMTP-1.00) for uid 13628 oleg@redhat.com; Mon, 9 Nov 2026 12:10:11 +0100 (CET) Date: Mon, 9 Nov 2026 12:10:08 +0100 From: Oleg Nesterov To: Zhao Gongyi Cc: catalin.marinas@arm.com, will@kernel.org, mark.rutland@arm.com, ruanjinjie@huawei.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] arm64: ptrace: don't warn on missing siginfo in a group-stop Message-ID: References: <20261105113051.97810-1-zhaogongyi@bytedance.com> <7fb3d264-ada7-4dfd-be21-05ce370686a0@bytedance.com> X-Archived-By: MIME-Version: 1.0 In-Reply-To: <7fb3d264-ada7-4dfd-be21-05ce370686a0@bytedance.com> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 X-Mimecast-MFC-PROC-ID: krbVwvOrAlRPe5VY2gi0XGgyunE2awpIVpZMTFf--fw_1794222612 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261109_031021_419934_4A9802F1 X-CRM114-Status: GOOD ( 16.83 ) X-Spam-Score: 0.5 (/) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" X-Spam-Status: No, score=-5.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On 11/09, Zhao Gongyi wrote: > > On 11/9/26 2:59 AM, Oleg Nesterov wrote: > > > > ---------------------------------------------------------------------------- > > But can't resist... The old comment was obviously wrong, the new one doesn't > > look clear to me. It correctly explains why info can be NULL, but not why we > > should not update orig_x0 in this case. May be it should just say that exit-stop > > always comes with info != NULL? > > > > You're right: the comment explains why info can be NULL, but not why we > return. The early return is intentional: it keeps orig_x0 unchanged > during a non-seized group-stop. Yep, this is what I meant. And this looks confusing to me. Lets suppose that the tracee was stopped because of JOBCTL_TRAP_STOP. Why should the behaviour of update_syscall_orig_x0_after_ptrace() depend on whether that tracee is PT_SEIZED or not? IOW. To me your V2 looks more understandable to me, I don't understand the Catalin's concerns. But then again, I can't really argue, I know nothing about arch/arm64. And I do remember that I tried to confuse you when I reviewed your V2 ;) Thanks again for correcting me. > I'll wait for Catalin and Will's thoughts on the wording. Me too. Oleg.