Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934297Ab3CZIpx (ORCPT ); Tue, 26 Mar 2013 04:45:53 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51147 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934170Ab3CZIpu (ORCPT ); Tue, 26 Mar 2013 04:45:50 -0400 Date: Tue, 26 Mar 2013 09:45:33 +0100 From: Anton Arapov To: Oleg Nesterov Cc: Srikar Dronamraju , LKML , Josh Stone , Frank Eigler , Peter Zijlstra , Ingo Molnar , Ananth N Mavinakayanahalli , adrian.m.negreanu@intel.com, Torsten.Polle@gmx.de Subject: Re: [PATCH 4/7] uretprobes: return probe entry, prepare_uretprobe() Message-ID: <20130326084533.GB22603@bandura.brq.redhat.com> References: <1363957745-6657-1-git-send-email-anton@redhat.com> <1363957745-6657-5-git-send-email-anton@redhat.com> <20130324152651.GC17037@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130324152651.GC17037@redhat.com> X-PGP-Key: http://people.redhat.com/aarapov/gpg User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1134 Lines: 46 On Sun, Mar 24, 2013 at 04:26:51PM +0100, Oleg Nesterov wrote: > On 03/22, Anton Arapov wrote: [snip] > And ->dirty looks confusing... perhaps ->chained ? > > ri = kzalloc(...); > if (!ri) > return; > > ret_vaddr = arch_uretprobe_hijack_return_addr(...); > if (ret_vaddr == -1) > goto err; > > if (ret_vaddr == trampoline_vaddr) { > if (!utask->return_instances) { > // This situation is not possible. > // (not sure we should send SIGSEGV) > pr_warn(...); > goto err; > } If we don't send SIGSEGV, does it make sense to restore the original return address that was just hijacked? So that we just decline setting the breakpoint for this very case. Anton. > > ri->chained = true; > ret_vaddr = utask->return_instances->orig_ret_vaddr; > } > > fill-ri-and-add-push-it; > return; > > err: > kfree(ri); > return; > > Oleg. > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/