From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 28252 invoked by alias); 23 Nov 2014 15:33:58 -0000 Mailing-List: contact gdb-prs-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-prs-owner@sourceware.org Received: (qmail 28218 invoked by uid 48); 23 Nov 2014 15:33:55 -0000 From: "eclipsehivernale at sfr dot fr" To: gdb-prs@sourceware.org Subject: [Bug server/16168] Signal heavy execution + repeated breakpoint locks up gbserver Date: Sun, 23 Nov 2014 15:33:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gdb X-Bugzilla-Component: server X-Bugzilla-Version: HEAD X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: eclipsehivernale at sfr dot fr X-Bugzilla-Status: NEW X-Bugzilla-Priority: P2 X-Bugzilla-Assigned-To: unassigned at sourceware dot org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Bugzilla-URL: http://sourceware.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-SW-Source: 2014-q4/txt/msg00303.txt.bz2 https://sourceware.org/bugzilla/show_bug.cgi?id=16168 --- Comment #4 from eclipsehivernale at sfr dot fr --- I am a software developer of a multi threaded application (about 10 threads). Recently we decided to use tcmalloc instead of the glibc malloc. It is a google open source malloc optimized for multi allocation allocation. Since this change, it is impossible to use gdbserver. The SIGPROF signal management is automatic in tcmalloc library. After a few "next" operation, gdbserver hangs, waiting for a pending event from thread which has received a SIGPROF signal, exactly like you describe in your comment. It is still possible to use gdb directly on the remote target, but this is a waste of time. I also observed once gdb hanged in native configuration, but I can't tell for sure it is the same issue as I just killed it and tried again. I tested the patch you posted: https://sourceware.org/ml/gdb-patches/2013-11/msg00361.html and it seems to work fine on 7.8.50.20141107. There are other freeze/hangs reported in the bug zilla database that may be linked to this issue, since it can appear by using any running operation (next, step, break...) and every gdb version so far are impacted. I think more and more people will face this issue (tcmalloc + multi threaded application without control on SIGPROF) and I would like to push to integrate a fix in the next version of gdb. Anyway thanks a lot to you for the investigation and the fix suggestion. If no action is taken to fix gdb then I guess I will use your fix locally forever. -- You are receiving this mail because: You are on the CC list for the bug.