Message ID | 1453942111-1215-4-git-send-email-donb@codesourcery.com |
---|---|
State | New, archived |
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Received: (qmail 60975 invoked by alias); 28 Jan 2016 00:48:40 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: <gdb-patches.sourceware.org> List-Unsubscribe: <mailto:gdb-patches-unsubscribe-##L=##H@sourceware.org> List-Subscribe: <mailto:gdb-patches-subscribe@sourceware.org> List-Archive: <http://sourceware.org/ml/gdb-patches/> List-Post: <mailto:gdb-patches@sourceware.org> List-Help: <mailto:gdb-patches-help@sourceware.org>, <http://sourceware.org/ml/#faqs> Sender: gdb-patches-owner@sourceware.org Delivered-To: mailing list gdb-patches@sourceware.org Received: (qmail 60931 invoked by uid 89); 28 Jan 2016 00:48:39 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=AWL, BAYES_00, RCVD_IN_DNSWL_NONE, SPF_PASS autolearn=ham version=3.3.2 spammy=subsequently, pthread_join, resumed, ecs 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, 28 Jan 2016 00:48:37 +0000 Received: from svr-orw-fem-03.mgc.mentorg.com ([147.34.97.39]) by relay1.mentorg.com with esmtp id 1aOalG-00049B-Uq from Don_Breazeal@mentor.com for gdb-patches@sourceware.org; Wed, 27 Jan 2016 16:48:34 -0800 Received: from build4-lucid-cs (147.34.91.1) by svr-orw-fem-03.mgc.mentorg.com (147.34.97.39) with Microsoft SMTP Server id 14.3.224.2; Wed, 27 Jan 2016 16:48:34 -0800 Received: by build4-lucid-cs (Postfix, from userid 1905) id 77DF941276; Wed, 27 Jan 2016 16:48:34 -0800 (PST) From: Don Breazeal <donb@codesourcery.com> To: <gdb-patches@sourceware.org> Subject: [PATCH 3/3] PR remote/19496, timeout in forking-threads-plus-bkpt Date: Wed, 27 Jan 2016 16:48:31 -0800 Message-ID: <1453942111-1215-4-git-send-email-donb@codesourcery.com> In-Reply-To: <1453942111-1215-1-git-send-email-donb@codesourcery.com> References: <1453942111-1215-1-git-send-email-donb@codesourcery.com> MIME-Version: 1.0 Content-Type: text/plain X-IsSubscribed: yes |
Commit Message
Don Breazeal
Jan. 28, 2016, 12:48 a.m. UTC
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: Add a call to set_running just before resuming the fork parent in infrun.c:handle_inferior_event_1. The call could be put elsewhere (e.g. in keep_going) but this approach makes the change for the case of resuming after a fork event, without potential side-effects for other cases where keep_going is called. Tested on x86_64 Linux and Nios II Linux target with x86 Linux host. Thanks, --Don gdb/ChangeLog: 2016-01-27 Don Breazeal <donb@codesourcery.com> PR remote/19496 * infrun.c (handle_inferior_event_1): Call set_running before resuming. --- gdb/infrun.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
Comments
On 01/28/2016 12:48 AM, Don Breazeal wrote: > > --- > gdb/infrun.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/gdb/infrun.c b/gdb/infrun.c > index 15210c9..e324864 100644 > --- a/gdb/infrun.c > +++ b/gdb/infrun.c > @@ -5232,7 +5232,13 @@ Cannot fill $_exitsignal with the correct signal number.\n")); > ecs->ptid = inferior_ptid; > > if (should_resume) > - keep_going (ecs); > + { > + /* Make sure the thread is marked as running. If the event > + occurred in the thread before we added it, it may have > + never been marked running. */ > + set_running (inferior_ptid, 1); > + keep_going (ecs); > + } > else > stop_waiting (ecs); > return; > Can you check whether this is still needed in current master? Specifically, whether a2077e254098 ([PATCH] Fix PR 19461: strange "info thread" behavior in non-stop) already fixed this? See: https://sourceware.org/ml/gdb-patches/2016-01/msg00446.html https://sourceware.org/bugzilla/show_bug.cgi?id=19461 Thanks, Pedro Alves
On 2/1/2016 4:05 AM, Pedro Alves wrote: > On 01/28/2016 12:48 AM, Don Breazeal wrote: > >> >> --- >> gdb/infrun.c | 8 +++++++- >> 1 file changed, 7 insertions(+), 1 deletion(-) >> >> diff --git a/gdb/infrun.c b/gdb/infrun.c >> index 15210c9..e324864 100644 >> --- a/gdb/infrun.c >> +++ b/gdb/infrun.c >> @@ -5232,7 +5232,13 @@ Cannot fill $_exitsignal with the correct signal number.\n")); >> ecs->ptid = inferior_ptid; >> >> if (should_resume) >> - keep_going (ecs); >> + { >> + /* Make sure the thread is marked as running. If the event >> + occurred in the thread before we added it, it may have >> + never been marked running. */ >> + set_running (inferior_ptid, 1); >> + keep_going (ecs); >> + } >> else >> stop_waiting (ecs); >> return; >> > > Can you check whether this is still needed in current master? > > Specifically, whether a2077e254098 ([PATCH] Fix PR 19461: strange "info thread" > behavior in non-stop) already fixed this? > > See: > https://sourceware.org/ml/gdb-patches/2016-01/msg00446.html > https://sourceware.org/bugzilla/show_bug.cgi?id=19461 > > Thanks, > Pedro Alves > Hi Pedro, It looks like my patch is still needed. FYI, the values of the variables used to determine whether to call set_running in your patch are this, in my failing test case: follow_child 0 detach_fork 1 non_stop 1 sched_multi 0 target_is_non_stop_p () 1 Thanks, --Don
On 02/01/2016 07:29 PM, Don Breazeal wrote: > On 2/1/2016 4:05 AM, Pedro Alves wrote: > Hi Pedro, > It looks like my patch is still needed. FYI, the values of the > variables used to determine whether to call set_running in your patch > are this, in my failing test case: > > follow_child 0 > detach_fork 1 > non_stop 1 > sched_multi 0 > target_is_non_stop_p () 1 Hmm. > 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. Thanks, Pedro Alves
diff --git a/gdb/infrun.c b/gdb/infrun.c index 15210c9..e324864 100644 --- a/gdb/infrun.c +++ b/gdb/infrun.c @@ -5232,7 +5232,13 @@ Cannot fill $_exitsignal with the correct signal number.\n")); ecs->ptid = inferior_ptid; if (should_resume) - keep_going (ecs); + { + /* Make sure the thread is marked as running. If the event + occurred in the thread before we added it, it may have + never been marked running. */ + set_running (inferior_ptid, 1); + keep_going (ecs); + } else stop_waiting (ecs); return;