From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from simark.ca by simark.ca with LMTP id Lrv9KgzG+WDpWQAAWB0awg (envelope-from ) for ; Thu, 22 Jul 2021 15:25:00 -0400 Received: by simark.ca (Postfix, from userid 112) id A23891EDFB; Thu, 22 Jul 2021 15:25:00 -0400 (EDT) X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on simark.ca X-Spam-Level: X-Spam-Status: No, score=-1.1 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_MSPIKE_H2,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 C5EE21E79C for ; Thu, 22 Jul 2021 15:24:59 -0400 (EDT) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 7B14D3839816 for ; Thu, 22 Jul 2021 19:24:59 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 7B14D3839816 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1626981899; bh=zQET+ZP+65Qw2og+umwTbuz+2axCtdMhXrwoXbYyRek=; h=Subject:To:References:Date:In-Reply-To:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc: From; b=FsPcwET21PKtmSoOiyg2IsxRtUPc5WAjsBSZQcmAaxPiBScgeEPT6ZZvGZCPz2GXp KSnLBmLPxHowaWRRC46DX+pNRVYbQNdUCzhSy6EnEdtqMNXI9xhohsY5NPaDzt+70A 9+rQpRTItj9KZv9NGespZk441VAodbU/BRajojfU= Received: from smtp.polymtl.ca (smtp.polymtl.ca [132.207.4.11]) by sourceware.org (Postfix) with ESMTPS id EEEC23839803 for ; Thu, 22 Jul 2021 19:24:38 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org EEEC23839803 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 16MJOU9R026642 (version=TLSv1/SSLv3 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 22 Jul 2021 15:24:34 -0400 DKIM-Filter: OpenDKIM Filter v2.11.0 smtp.polymtl.ca 16MJOU9R026642 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 019521E79C; Thu, 22 Jul 2021 15:24:29 -0400 (EDT) Subject: Re: [PATCHv2] Fix the crash at the end of the runtest To: Andrew Burgess , Bernd Edlinger References: <20210722124457.GC1872618@embecosm.com> <20210722132020.GD1872618@embecosm.com> <20210722165334.GE1872618@embecosm.com> Message-ID: <49c91167-8e3a-c436-28a4-f01a8fa64566@polymtl.ca> Date: Thu, 22 Jul 2021 15:24:29 -0400 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: <20210722165334.GE1872618@embecosm.com> 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 Thu, 22 Jul 2021 19:24:30 +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 Cc: "gdb-patches@sourceware.org" Errors-To: gdb-patches-bounces+public-inbox=simark.ca@sourceware.org Sender: "Gdb-patches" On 2021-07-22 12:53 p.m., Andrew Burgess wrote: > Thanks for the feedback. Below is the patch I intend to push first > thing tomorrow unless anyone objects. > > Thanks, > Andrew > > --- > > commit 41424acf01830d3cafb838a7d865985182edf47a > Author: Andrew Burgess > Date: Thu Jul 22 14:07:15 2021 +0100 > > gdb/testsuite: don't error when trying to unset last_spawn_tty_name > > In spawn_capture_tty_name (lib/gdb.exp) we either set or unset > last_spawn_tty_name depending on whether spawn_out(slave,name) exists > or not. > > One situation that might cause spawn_out(slave,name) to not exists is > if the spawn function is called with the argument -leaveopen, which is > how it is called when processes are created as part of a pipeline, the > created process has no tty, instead its output is written to a file > descriptor. > > If a pipeline is created consisting of multiple processes then there > will be multiple sequential calls to spawn, all using -leaveopen. The > first of these calls is fine, spawn_out(slave,name) is not set, and so > in spawn_capture_tty_name we unset last_spawn_tty_name. However, on > the second call to spawn, spawn_out(slave,name) is still not set and > so in spawn_capture_tty_name we again try to unset > last_spawn_tty_name, this now throws an error (as last_spawn_tty_name > is already unset). > > Fix this issue by using -nocomplain with the call to unset in > spawn_capture_tty_name. > > Before this commit I was seeing gdb.base/gnu-debugdata.exp report 1 > pass, and 1 unsupported test. After this commit I now see 16 passes > from this test script. > > I have also improved the code that used to do this: > > if { [info exists spawn_out] } { > set ::last_spawn_tty_name $spawn_out(slave,name) > } else { > ... > } > > The problem here is that we check for the existence of spawn_out, and > then unconditionally read spawn_out(slave,name). A situation could > arise where some other element of spawn_out is set, > e.g. spawn_out(foo), in which case we would enter the if block and try > to read a non-existent variable. After this commit we now check > specifically for spawn_out(slave,name). > > Finally, it is worth noting that before this issue was fixed runtest > itself, or rather the expect process behind runtest, would segfault > while exiting. I haven't looked at all into what the problem is here > that caused expect to crash, as fixing the bug in GDB's testing > scripts made the segfault go away. > > diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp > index e79e0622f9d..aeb8585bab9 100644 > --- a/gdb/testsuite/lib/gdb.exp > +++ b/gdb/testsuite/lib/gdb.exp > @@ -2029,10 +2029,20 @@ proc gdb_file_cmd { arg } { > proc spawn_capture_tty_name { args } { > set result [uplevel builtin_spawn $args] > upvar spawn_out spawn_out > - if { [info exists spawn_out] } { > + if { [info exists spawn_out(slave,name)] } { > set ::last_spawn_tty_name $spawn_out(slave,name) > } else { > - unset ::last_spawn_tty_name > + # If a process is spawned as part of a pipe line (e.g. passing > + # -leaveopen to the spawn proc) then the spawned process is no > + # assigned a tty and spawn_out(slave,name) will not be set. > + # In that case we want to ensure that last_spawn_tty_name is > + # not set. > + # > + # If the previous process spawned was also not assigned a tty > + # (e.g. multiple processed chained in a pipeline) then > + # last_spawn_tty_name will already be unset, so, if we don't > + # use -nocomplain here we would otherwise get an error. > + unset -nocomplain ::last_spawn_tty_name > } > return $result > } > LGTM, thanks! Simon