From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 110287 invoked by alias); 25 Feb 2016 17:29:38 -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 109452 invoked by uid 89); 25 Feb 2016 17:29:37 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.8 required=5.0 tests=AWL,BAYES_00,SPF_PASS autolearn=ham version=3.3.2 spammy=arrived, Hx-languages-length:4063, Our, sk:stepov X-HELO: relay1.mentorg.com Received: from relay1.mentorg.com (HELO relay1.mentorg.com) (192.94.38.131) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Thu, 25 Feb 2016 17:29:36 +0000 Received: from svr-orw-fem-04.mgc.mentorg.com ([147.34.97.41]) by relay1.mentorg.com with esmtp id 1aYzjJ-0000jD-IO from Don_Breazeal@mentor.com ; Thu, 25 Feb 2016 09:29:33 -0800 Received: from [172.30.2.193] (147.34.91.1) by SVR-ORW-FEM-04.mgc.mentorg.com (147.34.97.41) with Microsoft SMTP Server (TLS) id 14.3.224.2; Thu, 25 Feb 2016 09:29:33 -0800 Subject: [PING]Re: [PATCH v2 3/3] PR remote/19496, timeout in forking-threads-plus-bkpt To: , References: <1455150506-12760-1-git-send-email-donb@codesourcery.com> From: Don Breazeal Message-ID: <56CF39FD.90502@codesourcery.com> Date: Thu, 25 Feb 2016 17:29:00 -0000 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: <1455150506-12760-1-git-send-email-donb@codesourcery.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-IsSubscribed: yes X-SW-Source: 2016-02/txt/msg00814.txt.bz2 Ping Thanks, --Don On 2/10/2016 4:28 PM, Don Breazeal wrote: > On 2/1/2016 12:09 PM, Pedro Alves wrote: >> On 02/01/2016 07:29 PM, Don Breazeal wrote: >>> On 2/1/2016 4:05 AM, Pedro Alves wrote: >> >>> Hi Pedro, > ---snip--- >>> A fork event was reported to GDB before GDB knew about the parent thread, >>> followed immediately by a breakpoint event in a different thread. The >>> parent thread was subsequently added via remote_notice_new_inferior in >>> process_stop_reply, but when the thread was added the thread_info.state >>> was set to THREAD_STOPPED. The fork event was then handled correctly, >>> but when the fork parent was resumed via a call to keep_going, the state >>> was unchanged. >> >> Since this is non-stop, then it sounds to me like the bug is that the >> thread should have been added in THREAD_RUNNING state. >> >> Consider that infrun may be pulling target events out of the target_ops >> backend into its own event queue, but, not process them immediately. >> >> E.g., infrun may be stopping all threads temporarily for a step-over-breakpoint >> operation for thread A (stop_all_threads). The waitstatus of all threads >> is thus left pending in the thread structure (save_status), including the >> fork event of thread B. Right at this point, if the user >> does "info threads", that should show thread B (the fork parent) running, >> not stopped, even if internally, gdb is holding it paused for a little bit. >> > > Hi Pedro, > Here is a new patch that adds the threads with the state set to > THREAD_RUNNING for fork events. > Thanks! > --Don > > This patch addresses a failure in > gdb.threads/forking-threads-plus-breakpoint.exp: > > FAIL: gdb.threads/forking-threads-plus-breakpoint.exp: cond_bp_target=1: > detach_on_fork=on: inferior 1 exited (timeout) > > Cause: > A fork event was reported to GDB before GDB knew about the parent thread, > followed immediately by a breakpoint event in a different thread. The > parent thread was subsequently added via remote_notice_new_inferior in > process_stop_reply, but when the thread was added the thread_info.state > was set to THREAD_STOPPED. The fork event was then handled correctly, > but when the fork parent was resumed via a call to keep_going, the state > was unchanged. > > The breakpoint event was then handled, which caused all the non-breakpoint > threads to be stopped. When the breakpoint thread was resumed, all the > non-breakpoint threads were resumed via infrun.c:restart_threads. Our old > fork parent wasn't restarted, because it still had thread_info.state set to > THREAD_STOPPED. Ultimately the program under debug hung waiting for a > pthread_join while the old fork parent was stopped forever by GDB. > > Fix: > Make sure to add the fork parent thread in the THREAD_RUNNING state by > calling remote_notice_new_inferior with RUNNING set to 1 when processing > a fork stop reply. > > Tested on x86_64 Linux and Nios II Linux target with x86 Linux host. > > gdb/ChangeLog: > 2016-02-10 Don Breazeal > > * remote.c (process_stop_reply): Call remote_notice_new_inferior > with RUNNING set to 1 when handling fork events. > > --- > gdb/remote.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/gdb/remote.c b/gdb/remote.c > index f09a06e..ab750a7 100644 > --- a/gdb/remote.c > +++ b/gdb/remote.c > @@ -6818,7 +6818,14 @@ process_stop_reply (struct stop_reply *stop_reply, > VEC_free (cached_reg_t, stop_reply->regcache); > } > > - remote_notice_new_inferior (ptid, 0); > + /* If a fork event arrived before we knew about the parent thread, > + make sure to mark it as running when it is created. */ > + if (status->kind == TARGET_WAITKIND_FORKED > + || status->kind == TARGET_WAITKIND_VFORKED) > + remote_notice_new_inferior (ptid, 1); > + else > + remote_notice_new_inferior (ptid, 0); > + > remote_thr = demand_private_info (ptid); > remote_thr->core = stop_reply->core; > remote_thr->stop_reason = stop_reply->stop_reason; >