From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from simark.ca by simark.ca with LMTP id rPE7BXGGtWB/TQAAWB0awg (envelope-from ) for ; Mon, 31 May 2021 20:59:29 -0400 Received: by simark.ca (Postfix, from userid 112) id 0671C1F163; Mon, 31 May 2021 20:59:29 -0400 (EDT) X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on simark.ca X-Spam-Level: X-Spam-Status: No, score=-0.7 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,RDNS_DYNAMIC,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.2 Received: from sourceware.org (ip-8-43-85-97.sourceware.org [8.43.85.97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by simark.ca (Postfix) with ESMTPS id 4C8D31E01F for ; Mon, 31 May 2021 20:59:28 -0400 (EDT) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id C13AE385E440; Tue, 1 Jun 2021 00:59:27 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org C13AE385E440 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1622509167; bh=a/Mu50TRxMrGLWWrDDcUHjPW9lnIvofoLZGNMfLP80k=; h=Subject:To:References:Date:In-Reply-To:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To: From; b=BUF+pB1akOvqYwn5duyl5/0z0Jrr06yCEX+aRck0hFequALv/Z7o4o2GdvOYibGdD Fw1F4BQvubkcxrIKltr0sHfdR94NaRtTpWpRxVZ2F1k25iGh5zk2YoOCW3euXcUHXS MHgrzRADjUDMwgGbR6lZ+UIU/glvWwz9zeokZ6R0= Received: from smtp.polymtl.ca (smtp.polymtl.ca [132.207.4.11]) by sourceware.org (Postfix) with ESMTPS id E10B1385E440 for ; Tue, 1 Jun 2021 00:59:25 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org E10B1385E440 Received: from simark.ca (simark.ca [158.69.221.121]) (authenticated bits=0) by smtp.polymtl.ca (8.14.7/8.14.7) with ESMTP id 1510xIIa000919 (version=TLSv1/SSLv3 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 31 May 2021 20:59:23 -0400 DKIM-Filter: OpenDKIM Filter v2.11.0 smtp.polymtl.ca 1510xIIa000919 Received: from [10.0.0.11] (192-222-157-6.qc.cable.ebox.net [192.222.157.6]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by simark.ca (Postfix) with ESMTPSA id C0ACF1E01F; Mon, 31 May 2021 20:59:18 -0400 (EDT) Subject: Re: [PATCH] Conditionally restore displaced stepping state after fork. To: John Baldwin , gdb-patches@sourceware.org References: <20210531161558.10600-1-jhb@FreeBSD.org> Message-ID: <35b34a01-3790-d3dd-cacc-2f6320e8d2c5@polymtl.ca> Date: Mon, 31 May 2021 20:59:18 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <20210531161558.10600-1-jhb@FreeBSD.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Poly-FromMTA: (simark.ca [158.69.221.121]) at Tue, 1 Jun 2021 00:59:18 +0000 X-BeenThere: gdb-patches@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Simon Marchi via Gdb-patches Reply-To: Simon Marchi Errors-To: gdb-patches-bounces@sourceware.org Sender: "Gdb-patches" On 2021-05-31 12:15 p.m., John Baldwin wrote: > There is no default method for > gdbarch_displaced_step_restore_all_in_ptid, so calling it > unconditionally for fork events triggered an assertion failure on > platforms that do not support displaced stepping. To fix, only invoke > the method if the gdbarch supports displaced stepping. > > gdb/ChangeLog: > > * infrun.c (handle_inferior_event): Only call > gdbarch_displaced_step_restore_all_in_ptid if > gdbarch_supports_displaced_stepping is true. > --- > gdb/ChangeLog | 6 ++++++ > gdb/infrun.c | 3 ++- > 2 files changed, 8 insertions(+), 1 deletion(-) > > diff --git a/gdb/ChangeLog b/gdb/ChangeLog > index 03910c0634..b0f448a35e 100644 > --- a/gdb/ChangeLog > +++ b/gdb/ChangeLog > @@ -1,3 +1,9 @@ > +2021-05-30 John Baldwin > + > + * infrun.c (handle_inferior_event): Only call > + gdbarch_displaced_step_restore_all_in_ptid if > + gdbarch_supports_displaced_stepping is true. > + > 2021-05-27 Simon Marchi > > * Fix tab after space indentation issues throughout. > diff --git a/gdb/infrun.c b/gdb/infrun.c > index e9624d2a9b..6fd077796f 100644 > --- a/gdb/infrun.c > +++ b/gdb/infrun.c > @@ -5496,7 +5496,8 @@ handle_inferior_event (struct execution_control_state *ecs) > /* If this is a fork (child gets its own address space copy) and some > displaced step buffers were in use at the time of the fork, restore > the displaced step buffer bytes in the child process. */ > - if (ecs->ws.kind == TARGET_WAITKIND_FORKED) > + if (ecs->ws.kind == TARGET_WAITKIND_FORKED > + && gdbarch_supports_displaced_stepping (gdbarch)) > gdbarch_displaced_step_restore_all_in_ptid > (gdbarch, parent_inf, ecs->ws.value.related_pid); gdbarch_supports_displaced_stepping checks whether the gdbarch implement gdbarch_displaced_step_prepare. But a gdbarch could technically implement gdbarch_displaced_step_prepare and not gdbarch_displaced_step_restore_all_in_ptid. Would it be useful though? If not, we force that arches implementing gdbarch_displaced_step_prepare also implement gdbarch_displaced_step_restore_all_in_ptid by using a post-check on gdbarch creation (like we check that if an arch implements gdbarch_displaced_step_prepare, it also implements gdbarch_displaced_step_finish). In that case, checking gdbarch_supports_displaced_stepping here will be sufficient. If there's a case for having gdbarch_displaced_step_prepare but not gdbarch_displaced_step_restore_all_in_ptid, then we would probably need to use gdbarch_displaced_step_restore_all_in_ptid_p. But I don't see a use case for that, so I'd go with the other solution. Simon