From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 10133 invoked by alias); 29 Jul 2014 21:48:44 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Received: (qmail 10117 invoked by uid 89); 29 Jul 2014 21:48:44 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-3.2 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_LOW,RP_MATCHES_RCVD,SPF_PASS autolearn=ham version=3.3.2 X-HELO: mail-vc0-f174.google.com Received: from mail-vc0-f174.google.com (HELO mail-vc0-f174.google.com) (209.85.220.174) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES128-SHA encrypted) ESMTPS; Tue, 29 Jul 2014 21:48:42 +0000 Received: by mail-vc0-f174.google.com with SMTP id la4so532562vcb.19 for ; Tue, 29 Jul 2014 14:48:40 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:cc:content-type; bh=m3Jjh3pPD/63NqWuXy4mMvaloirFN0Kn4kndk/17AJc=; b=Sh8SuWW78m7bu3ireUQFkHhPQ76JTBHcgUuc2q090JSETdlktXB9n1kzaVrvuEZ0zM P45HWuIBOe50Crqb054mSBpEyOx5IzaYi1jJLOZIKzwZrJVDGMkhwZpAcqFWKctIAD6f D/fNZdeBelbrQyOPEzLxeq4YE3mYcxM0fhqVOl4E7kR1iPAtcUT0Hlf7sEU9EkAXXysC ECeILX8+zC3bpsgKcNWCZKppkWwC7uuwd2ouzz56HOhrGnoYcJUzJOmNM9PnsUwvHxY+ rMay3L+bM9sygNXiBMWMD8dOvdbikbTYkjAHvWubLmZzlK6iLvkSzKdtcbjmY/cDWQ7b RcDQ== X-Gm-Message-State: ALoCoQljmq70+j+jZ3+UcuJpkjQt41il5c2MHKx+M24iiEBBTZEFQdJaUBRMQccicaTNoZvL0cUN MIME-Version: 1.0 X-Received: by 10.220.192.129 with SMTP id dq1mr4718033vcb.57.1406670520075; Tue, 29 Jul 2014 14:48:40 -0700 (PDT) Received: by 10.52.28.233 with HTTP; Tue, 29 Jul 2014 14:48:39 -0700 (PDT) In-Reply-To: <53BD7749.5000800@redhat.com> References: <1400878753-24688-1-git-send-email-palves@redhat.com> <538739A2.2050105@redhat.com> <20140701162830.GA25877@host2.jankratochvil.net> <1404291574.3766.35.camel@bordewijk.wildebeest.org> <53B3CDCC.9050502@redhat.com> <53B57911.10304@redhat.com> <53B6B0B8.2050702@redhat.com> <21434.52532.737427.778289@ruffy.mtv.corp.google.com> <53BC0D0B.7040001@redhat.com> <21437.28600.751354.629884@ruffy.mtv.corp.google.com> <53BD7749.5000800@redhat.com> Date: Tue, 29 Jul 2014 22:03:00 -0000 Message-ID: Subject: Re: [pushed+7.8] Re: [PATCH] Fix "attach" command vs user input race [Re: Regression for attach from stdin [Re: [pushed] Re: [PATCH v6 0/2] enable target-async by default]] From: Doug Evans To: Pedro Alves Cc: gdb-patches Content-Type: text/plain; charset=UTF-8 X-IsSubscribed: yes X-SW-Source: 2014-07/txt/msg00772.txt.bz2 On Wed, Jul 9, 2014 at 10:09 AM, Pedro Alves wrote: > On 07/09/2014 05:37 PM, Doug Evans wrote: > >> spurious change > > Fixed. > >> I like this a lot better. Thanks. >> The patch is ok with me, modulo removing the spurious change. > > Here's what I pushed to both master and gdb-7.8-branch. > > Thanks. > > ------------- > From 1fe2833b6dd03602ba86aa334e81466ea9abe66a Mon Sep 17 00:00:00 2001 > From: Pedro Alves > Date: Wed, 9 Jul 2014 17:52:58 +0100 > Subject: [PATCH] Fix "attach" command vs user input race > > On async targets, a synchronous attach is done like this: > > #1 - target_attach is called (PTRACE_ATTACH is issued) > #2 - a continuation is installed > #3 - we go back to the event loop > #4 - target reports stop (SIGSTOP), event loop wakes up, and > attach continuation is called > #5 - among other things, the continuation calls > target_terminal_inferior, which removes stdin from the event > loop > > Note that in #3, GDB is still processing user input. If the user is > fast enough, e.g., with something like: > > echo -e "attach PID\nset xxx=1" | gdb > > ... then the "set" command is processed before the attach completes. > > We get worse behavior even, if input is a tty and therefore > readline/editing is enabled, with e.g.,: > > (gdb) attach PID\nset xxx=1 > > we then crash readline/gdb, with: > > Attaching to program: attach-wait-input, process 14537 > readline: readline_callback_read_char() called with no handler! > Aborted > $ > > Fix this by calling target_terminal_inferior before #3 above. > > The test covers both scenarios by running with editing/readline forced > to both on and off. > > gdb/ > 2014-07-09 Pedro Alves > > * infcmd.c (attach_command_post_wait): Don't call > target_terminal_inferior here. > (attach_command): Call it here instead. > > gdb/testsuite/ > 2014-07-09 Pedro Alves > > * gdb.base/attach-wait-input.exp: New file. > * gdb.base/attach-wait-input.c: New file. Hi. Is this TODO still needed after this patch? infcmd.c: /* * TODO: * Should save/restore the tty state since it might be that the * program to be debugged was started on this tty and it wants * the tty in some state other than what we want. If it's running * on another terminal or without a terminal, then saving and * restoring the tty state is a harmless no-op. * This only needs to be done if we are attaching to a process. */