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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-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7fb3d264-ada7-4dfd-be21-05ce370686a0@bytedance.com> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 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.