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Fri, 23 Oct 2026 13:24:08 +0000 (UTC) Received: from onestero-thinkpadp1gen7.tpbc.csb (headnet04.pony-001.prod.iad2.dc.redhat.com [10.2.32.116]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with SMTP id BB84D195608C; Fri, 23 Oct 2026 13:24:05 +0000 (UTC) Received: by onestero-thinkpadp1gen7.tpbc.csb (nbSMTP-1.00) for uid 13628 oleg@redhat.com; Fri, 23 Oct 2026 15:24:07 +0200 (CEST) Date: Fri, 23 Oct 2026 15:24:04 +0200 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 v2] arm64: ptrace: don't warn on missing siginfo in a group-stop Message-ID: References: <20261023110710.10145-1-zhaogongyi@bytedance.com> X-Archived-By: MIME-Version: 1.0 In-Reply-To: <20261023110710.10145-1-zhaogongyi@bytedance.com> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 X-Mimecast-MFC-PROC-ID: 0zNY-ENe-lwA-ZiAyZ5AEv6mR0mnyBTX_SUq2vkzwnU_1792761849 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-20261023_142425_589861_C070E04B X-CRM114-Status: GOOD ( 16.33 ) X-Spam-Score: 2.7 (++) 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=-11.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=ham 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 10/23, Zhao Gongyi wrote: > > --- a/arch/arm64/kernel/ptrace.c > +++ b/arch/arm64/kernel/ptrace.c > @@ -573,10 +573,6 @@ static void update_syscall_orig_x0_after_ptrace(struct task_struct *target) > if (regs->syscallno == NO_SYSCALL) > return; > > - /* We should only be called when target is in a ptrace stop */ > - if (WARN_ON_ONCE(!info)) > - return; > - > /* > * For compat tasks, orig_r0 is provided directly through GPR index > * 17. > @@ -588,7 +584,7 @@ static void update_syscall_orig_x0_after_ptrace(struct task_struct *target) > * Don't update orig_x0 for a syscall-exit-stop, as x0 now contains the > * return value of the system call. > */ > - if ((info->si_code & ~0x80) == SIGTRAP && > + if (info && (info->si_code & ~0x80) == SIGTRAP && > target->ptrace_message == PTRACE_EVENTMSG_SYSCALL_EXIT) { > return; LGTM, but I don't understand this arm-specific code. And... Do we need to check target->last_siginfo at all? ptrace_signal() -> ptrace_stop() path sets ->ptrace_message = 0. In all other cases: if info != NULL, then .si_code == target->exit_code. ptrace_event(event) users always use event != 0 and != 0x80. So it seems that we can just do if ((target->exit_code & ~0x80) == SIGTRAP && target->ptrace_message == PTRACE_EVENTMSG_SYSCALL_EXIT) ? I'll recheck... If I am right, perhaps it makes sense to simplify ptrace_get_syscall_info_op(). Anyway, up to you. Oleg.