From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 29962 invoked by alias); 28 Oct 2014 12:10:02 -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 29935 invoked by uid 89); 28 Oct 2014 12:10:01 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.3 required=5.0 tests=AWL,BAYES_00,RP_MATCHES_RCVD,SPF_HELO_PASS,SPF_PASS autolearn=ham version=3.3.2 X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Tue, 28 Oct 2014 12:10:00 +0000 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s9SC9u25021270 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Tue, 28 Oct 2014 08:09:57 -0400 Received: from [127.0.0.1] (ovpn01.gateway.prod.ext.ams2.redhat.com [10.39.146.11]) by int-mx14.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id s9SC9sZD026970; Tue, 28 Oct 2014 08:09:55 -0400 Message-ID: <544F8792.5050800@redhat.com> Date: Tue, 28 Oct 2014 12:10:00 -0000 From: Pedro Alves User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.1.1 MIME-Version: 1.0 To: Sandra Loosemore CC: gdb-patches@sourceware.org Subject: [pushed] Workaround remote targets that report an empty list to qfThreadInfo (Re: Cannot execute this command without a live selected thread.) References: <544A7648.6060102@codesourcery.com> <544A7930.4040909@redhat.com> <544A8741.9090705@codesourcery.com> <544A8B0C.5000509@redhat.com> <544A8F15.9000906@redhat.com> <544EA2C9.8090902@codesourcery.com> In-Reply-To: <544EA2C9.8090902@codesourcery.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-SW-Source: 2014-10/txt/msg00752.txt.bz2 On 10/27/2014 07:53 PM, Sandra Loosemore wrote: > On 10/24/2014 11:40 AM, Pedro Alves wrote: >> >> Please give this a try. >> >> From 2062235a91a3c69e73c39b0f8a4f78f4ec396931 Mon Sep 17 00:00:00 2001 >> From: Pedro Alves >> Date: Fri, 24 Oct 2014 18:27:14 +0100 >> Subject: [PATCH] gdb/ 2014-10-24 Pedro Alves >> >> * remote.c (remote_thread_alive): New, factored out from ... >> (remote_thread_alive): ... this. >> (remote_update_thread_list): Bail out before deleting threads if >> the target returned an empty list, and, the current thread has a >> magic/fake ptid. > > This worked for me. The remaining ERRORs in the nios2-elf test results > are due to the GCC switch to C11. Thanks Sandra, now pushed. >From 7d1a114c44db3d7055afe48868f939ba95a64b7b Mon Sep 17 00:00:00 2001 From: Pedro Alves Date: Tue, 28 Oct 2014 11:35:10 +0000 Subject: [PATCH] Workaround remote targets that report an empty list to qfThreadInfo In https://sourceware.org/ml/gdb-patches/2014-10/msg00652.html, Sandra shows a target that was broken by the recent update_thread_list optimization: (gdb) target remote qa8-centos32-cs:10514 ... (gdb) continue Continuing. Cannot execute this command without a live selected thread. (gdb) The error means that the current thread is in "exited" state when the continue command is processed. The root of the problem was found here: > Sending packet: $Hg0#df...Packet received: ... > Sending packet: $?#3f...Packet received: S00 > Sending packet: $qfThreadInfo#bb...Packet received: l > Sending packet: $Hc-1#09...Packet received: > Sending packet: $qC#b4...Packet received: unset This target doesn't really support threads (no thread indication in stop reply packets; no support for qC), but then supports qfThreadInfo, and returns an empty thread list to GDB. See https://sourceware.org/ml/gdb-patches/2014-10/msg00665.html for why the target does that. As remote_update_thread_list deletes threads from GDB's list that are not found in the thread list that the target reports, the result is that GDB deletes the "fake" main thread that GDB added itself. (As that thread is currently selected, it is marked "exited" instead of being deleted straight away.) This commit avoids deleting the main thread in this scenario. gdb/ 2014-10-27 Pedro Alves * remote.c (remote_thread_alive): New, factored out from ... (remote_thread_alive): ... this. (remote_update_thread_list): Bail out before deleting threads if the target returned an empty list, and, the current thread has a magic/fake ptid. --- gdb/ChangeLog | 8 ++++++++ gdb/remote.c | 35 ++++++++++++++++++++++++++++++++--- 2 files changed, 40 insertions(+), 3 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 8a34118..b358dd7 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,5 +1,13 @@ 2014-10-27 Pedro Alves + * remote.c (remote_thread_alive): New, factored out from ... + (remote_thread_alive): ... this. + (remote_update_thread_list): Bail out before deleting threads if + the target returned an empty list, and, the current thread has a + magic/fake ptid. + +2014-10-27 Pedro Alves + * infrun.c (handle_signal_stop): Also skip handlers when a random signal arrives while handling a "stepi" or a "nexti". Set the thread's 'step_after_step_resume_breakpoint' flag. diff --git a/gdb/remote.c b/gdb/remote.c index 20f2988..4b9b099 100644 --- a/gdb/remote.c +++ b/gdb/remote.c @@ -1842,11 +1842,11 @@ set_general_process (void) } -/* Return nonzero if the thread PTID is still alive on the remote - system. */ +/* Return nonzero if this is the main thread that we made up ourselves + to model non-threaded targets as single-threaded. */ static int -remote_thread_alive (struct target_ops *ops, ptid_t ptid) +remote_thread_always_alive (struct target_ops *ops, ptid_t ptid) { struct remote_state *rs = get_remote_state (); char *p, *endp; @@ -1861,6 +1861,23 @@ remote_thread_alive (struct target_ops *ops, ptid_t ptid) multi-threading. */ return 1; + return 0; +} + +/* Return nonzero if the thread PTID is still alive on the remote + system. */ + +static int +remote_thread_alive (struct target_ops *ops, ptid_t ptid) +{ + struct remote_state *rs = get_remote_state (); + char *p, *endp; + + /* Check if this is a thread that we made up ourselves to model + non-threaded targets as single-threaded. */ + if (remote_thread_always_alive (ops, ptid)) + return 1; + p = rs->buf; endp = rs->buf + get_remote_packet_size (); @@ -2780,6 +2797,18 @@ remote_update_thread_list (struct target_ops *ops) got_list = 1; + if (VEC_empty (thread_item_t, context.items) + && remote_thread_always_alive (ops, inferior_ptid)) + { + /* Some targets don't really support threads, but still + reply an (empty) thread list in response to the thread + listing packets, instead of replying "packet not + supported". Exit early so we don't delete the main + thread. */ + do_cleanups (old_chain); + return; + } + /* CONTEXT now holds the current thread list on the remote target end. Delete GDB-side threads no longer found on the target. */ -- 1.9.3