From patchwork Thu Feb 11 00:28:26 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Don Breazeal X-Patchwork-Id: 10816 Received: (qmail 68121 invoked by alias); 11 Feb 2016 00:28:30 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Delivered-To: mailing list gdb-patches@sourceware.org Received: (qmail 68107 invoked by uid 89); 11 Feb 2016 00:28:30 -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, RCVD_IN_DNSWL_NONE, SPF_PASS autolearn=ham version=3.3.2 spammy=sk:stepov, sk:step-ov, arrived, hung 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, 11 Feb 2016 00:28:29 +0000 Received: from svr-orw-fem-04.mgc.mentorg.com ([147.34.97.41]) by relay1.mentorg.com with esmtp id 1aTf7S-0001Hd-CX from Don_Breazeal@mentor.com ; Wed, 10 Feb 2016 16:28:26 -0800 Received: from build2-lucid-cs (147.34.91.1) by svr-orw-fem-04.mgc.mentorg.com (147.34.97.41) with Microsoft SMTP Server id 14.3.224.2; Wed, 10 Feb 2016 16:28:26 -0800 Received: by build2-lucid-cs (Postfix, from userid 1905) id 04BC93A01CA; Wed, 10 Feb 2016 16:28:25 -0800 (PST) From: Don Breazeal To: , Subject: [PATCH v2 3/3] PR remote/19496, timeout in forking-threads-plus-bkpt Date: Wed, 10 Feb 2016 16:28:26 -0800 Message-ID: <1455150506-12760-1-git-send-email-donb@codesourcery.com> In-Reply-To: <56AFBB80.1010209@redhat.com> MIME-Version: 1.0 X-IsSubscribed: yes 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;