From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 66771 invoked by alias); 6 Dec 2019 16:19:29 -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 66762 invoked by uid 89); 6 Dec 2019 16:19:28 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-11.9 required=5.0 tests=BAYES_00,GIT_PATCH_2,GIT_PATCH_3 autolearn=ham version=3.3.1 spammy=Program, sk:scoped_, user-visible, ps2 X-HELO: mx1.osci.io Received: from polly.osci.io (HELO mx1.osci.io) (8.43.85.229) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Fri, 06 Dec 2019 16:19:26 +0000 Received: by mx1.osci.io (Postfix, from userid 994) id EFA0F20456; Fri, 6 Dec 2019 11:19:24 -0500 (EST) Received: from gnutoolchain-gerrit.osci.io (gnutoolchain-gerrit.osci.io [IPv6:2620:52:3:1:5054:ff:fe06:16ca]) by mx1.osci.io (Postfix) with ESMTP id C06042032B; Fri, 6 Dec 2019 11:19:22 -0500 (EST) Received: from localhost (localhost [127.0.0.1]) by gnutoolchain-gerrit.osci.io (Postfix) with ESMTP id 9E42F2816F; Fri, 6 Dec 2019 11:19:22 -0500 (EST) X-Gerrit-PatchSet: 2 Date: Fri, 06 Dec 2019 16:19:00 -0000 From: "Pedro Alves (Code Review)" To: Tankut Baris Aktemur , gdb-patches@sourceware.org Cc: Luis Machado Auto-Submitted: auto-generated X-Gerrit-MessageType: comment Subject: [review v2] infrun: handle already-exited threads when attempting to stop X-Gerrit-Change-Id: I7cec98f40283773b79255d998511da434e9cd408 X-Gerrit-Change-Number: 133 X-Gerrit-ChangeURL: X-Gerrit-Commit: a32b3dcee11cd3a9f40c5f07757a514074b9051f In-Reply-To: References: X-Gerrit-Comment-Date: Fri, 6 Dec 2019 11:19:22 -0500 Reply-To: gnutoolchain-gerrit@osci.io MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Disposition: inline User-Agent: Gerrit/3.0.3-79-g83ff7f88f1 Content-Type: text/plain; charset=UTF-8 Message-Id: <20191206161922.9E42F2816F@gnutoolchain-gerrit.osci.io> X-SW-Source: 2019-12/txt/msg00231.txt.bz2 Pedro Alves has posted comments on this change. Change URL: https://gnutoolchain-gerrit.osci.io/r/c/binutils-gdb/+/133 ...................................................................... Patch Set 2: (1 comment) | --- gdb/infrun.c | +++ gdb/infrun.c | @@ -4494,7 +4509,19 @@ stop_all_threads (void) | + if (ws.kind == TARGET_WAITKIND_THREAD_EXITED) | + delete_thread (t); | + else | + { | + /* TARGET_WAITKIND_EXITED or | + TARGET_WAITKIND_SIGNALLED. */ | + /* Need to restore the context because | + handle_inferior_exit switches it. */ | + scoped_restore_current_pspace_and_thread restore; | + handle_inferior_exit (event_ptid, ws); PS2, Line 4518: Sorry, but this doesn't look right. We're inside stop_all_threads, processing some other event, and a process exit event for one of the processes we're trying to stop comes along, and this processes it right away. Once the stop_all_threads dance is done, we go back to handling the original event, and possibly reporting a stop to the user. Meanwhile, whatever state that was set by handle_inferior_exit, like e.g. $_exitcode, is lost, or now incorrect for the reported stop. We also never present a stop on the CLI for that "spurious" process exit. Here: (gdb) continue Continuing. Executing on build: kill -9 29412 29417 (timeout = 300) spawn -ignore SIGHUP kill -9 29412 29417 Program terminated with signal SIGKILL, Killed. The program no longer exists. <<<<<<<<<<< no user-visible stop / prompt here. <<<<<<<<<<<<<<< Program terminated with signal SIGKILL, Killed. The program no longer exists. (gdb) PASS: gdb.multi/multi-kill.exp: iteration 1: back to gdb prompt The fix for this I think must be around leaving the TARGET_WAITKIND_EXITED/TARGET_WAITKIND_SIGNALLED event pending, so that it is processed later when we're out of the stop_all_threads loop and back to dequeuing the next event. gdb/linux-nat.c also has its own "stop all threads temporarily" logic, and that does that -- leaves process exits pending. See wait_lwp: /* If this is the leader exiting, it means the whole process is gone. Store the status to report to the core. Store it in lp->waitstatus, because lp->status would be ambiguous (W_EXITCODE(0,0) == 0). */ store_waitstatus (&lp->waitstatus, status); return 0; | + } | + } | } | else | { | thread_info *t = find_thread_ptid (event_ptid); | if (t == NULL) | t = add_thread (event_ptid); | -- Gerrit-Project: binutils-gdb Gerrit-Branch: master Gerrit-Change-Id: I7cec98f40283773b79255d998511da434e9cd408 Gerrit-Change-Number: 133 Gerrit-PatchSet: 2 Gerrit-Owner: Tankut Baris Aktemur Gerrit-Reviewer: Luis Machado Gerrit-Reviewer: Pedro Alves Gerrit-Reviewer: Tankut Baris Aktemur Gerrit-Comment-Date: Fri, 06 Dec 2019 16:19:22 +0000 Gerrit-HasComments: Yes Gerrit-Has-Labels: No Gerrit-MessageType: comment