From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <49133665.8090701@redhat.com> Date: Thu, 06 Nov 2008 12:24:37 -0600 From: David Smith MIME-Version: 1.0 Subject: Re: [patch 15/21] ptrace changes References: <20081001083317.782967473@de.ibm.com> <20081001084129.042880937@de.ibm.com> <490F317C.9040603@redhat.com> <1225885284.17430.7.camel@localhost> In-Reply-To: <1225885284.17430.7.camel@localhost> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: To: schwidefsky@de.ibm.com Cc: linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, Heiko Carstens List-ID: Martin Schwidefsky wrote: > On Mon, 2008-11-03 at 11:14 -0600, David Smith wrote: > >> Is this correct, or should the 1st syscall argument be found in >> regs->orig_gpr2 by syscall_get_arguments()/syscall_set_arguments()? > > The question is when do syscall_get_arguments and syscall_set_arguments > functions get called? If they are called on a call chain that started > from do_syscall_trace_enter then we'd have to use orig_gpr2 instead of > gprs[2] but if the functions are not called via do_syscall_trace_enter > the first argument is located in grprs[2]. As far as I can see the sole > user of syscall_get_arguments is collect_syscall which is used to get > the registers of a blocked process. In this case the kernel call chain > does not include do_syscall_trace_enter, therefore the first argument is > in gprs[2], no? But, collect_syscall() also calls syscall_get_nr(): *callno = syscall_get_nr(target, regs); if (*callno != -1L && maxargs > 0) syscall_get_arguments(target, regs, 0, maxargs, args); Both syscall_get_nr() *and* syscall_get_arguments() returning gprs[2] can't be right, can it? -- David Smith dsmith@redhat.com Red Hat http://www.redhat.com 256.217.0141 (direct) 256.837.0057 (fax)