From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from simark.ca by simark.ca with LMTP id 2OB5MYUwU2EHBQAAWB0awg (envelope-from ) for ; Tue, 28 Sep 2021 11:11:01 -0400 Received: by simark.ca (Postfix, from userid 112) id C70FA1EE25; Tue, 28 Sep 2021 11:11:01 -0400 (EDT) X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on simark.ca X-Spam-Level: X-Spam-Status: No, score=-2.0 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,NICE_REPLY_A,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.2 Received: from sourceware.org (server2.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 ED14A1EDDB for ; Tue, 28 Sep 2021 11:11:00 -0400 (EDT) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 77326385843A for ; Tue, 28 Sep 2021 15:11:00 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 77326385843A DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1632841860; bh=Xsp3TnoDZ2yuiYtZYqhuUBTAdOF8reRRjOsH/c4XFbc=; 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=Zj0w/br58PxTn5k3ClUcklr30ifrrIHNiv8EyUgt3lG8fxJFkO0clIszTieYMD16A TpPBlro9URQhlNzqFERW5Sw9RRiCG9Thai89EyaFoi/2VMmXyuaPgrVsu0ku+vIR02 r2bKeukqyfmIrpOWGgM2UgKFwOPWsSkf35G6wigs= Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by sourceware.org (Postfix) with ESMTPS id B4C853858408 for ; Tue, 28 Sep 2021 15:10:42 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org B4C853858408 Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id BED8C224E5; Tue, 28 Sep 2021 15:10:41 +0000 (UTC) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 9D88D13CE6; Tue, 28 Sep 2021 15:10:41 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id 9NLvJHEwU2HfYgAAMHmgww (envelope-from ); Tue, 28 Sep 2021 15:10:41 +0000 Subject: Re: [PATCH 6/6] gdb: don't share aspace/pspace on fork with "detach-on-fork on" and "follow-fork-mode child" To: Simon Marchi , John Baldwin , Simon Marchi , gdb-patches@sourceware.org References: <20210910205402.3853607-1-simon.marchi@efficios.com> <20210910205402.3853607-6-simon.marchi@efficios.com> <021ba846-e43e-e6ef-c827-7e2b8ff8f5e9@FreeBSD.org> <58ca5b53-9d70-b8e7-e4c9-86b9f080f731@polymtl.ca> <41efe1d2-64fe-b0d1-029f-363bfc567bf5@polymtl.ca> Message-ID: Date: Tue, 28 Sep 2021 17:10:41 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: <41efe1d2-64fe-b0d1-029f-363bfc567bf5@polymtl.ca> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit 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: Tom de Vries via Gdb-patches Reply-To: Tom de Vries Errors-To: gdb-patches-bounces+public-inbox=simark.ca@sourceware.org Sender: "Gdb-patches" On 9/27/21 9:32 PM, Simon Marchi via Gdb-patches wrote: > On 2021-09-10 23:16, Simon Marchi via Gdb-patches wrote: >>>> Note that the problem described above happens today with "detach-on-fork >>>> off" and "follow-fork-mode child", because we create new spaces for the >>>> child. This will have to be addressed later. >>>> >>>> Test-wise, improve gdb.base/foll-fork.exp to set a breakpoint that is >>>> expected to have a location in each inferiors. Without the fix, when >>>> the two inferiors erroneously share a program space, GDB reports a >>>> single location. >>> >>> So I wonder about the case where follow-fork-mode is parent and >>> detach-on-fork is off? In that case, should the existing aspace/pspace >>> stay with the parent and the child get clones? That is, using the >>> follow-fork-mode setting to determine which inferior gets the existing >>> aspace/pspace and assigning the cloned copies to the !follow-fork-mode >>> inferior? >> >> I think that would work, to address the problem described above. > > FYI, I tried doing the above (giving the original program space to the > child with "follow-fork-mode child" and "detach-on-fork off") and I hit > some problems. Attached to the program space is the list of shared > libraries. So GDB would now think the parent has no shared library. I > added a solib_create_inferior_hook call to force re-discovering the > shared libraries in the parent. That seemed to work, but then in MI > there were spurious =library-loaded events that made it look like > inferior 1 re-loaded shared libraries. I'm also worried about what > other per-program space is kept, that could cause some kind of trouble > for the parent. So I will put this off for now, as it's not something > that should be done in a rush, I think. > > In the mean time, I'll re-test this series and push it if all seems > good. I'm seeing: ... (gdb) PASS: gdb.base/foll-fork.exp: follow-fork-mode=child: detach-on-fork=on: cmd=next 2: test_follow_fork: break callee info breakpoints 2^M Num Type Disp Enb Address What^M 2 breakpoint keep y ^M 2.1 y 0x00000000004005ae in callee at /home/vries/gdb_versions/devel/src/gdb/testsuite/gdb.base/foll-fork.c:9 inf 2^M 2.2 y 0x00000000004005ae in callee at /home/vries/gdb_versions/devel/src/gdb/testsuite/gdb.base/foll-fork.c:9 inf 1^M (gdb) FAIL: gdb.base/foll-fork.exp: follow-fork-mode=child: detach-on-fork=on: cmd=next 2: test_follow_fork: info breakpoints ... Looks like the test-case expects first inf 1, then inf 2, and this is the other way around. Should the test-case regexp be updated? Thanks, - Tom