From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 25861 invoked by alias); 20 Nov 2001 07:55:34 -0000 Mailing-List: contact gdb-patches-help@sourceware.cygnus.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sources.redhat.com Received: (qmail 25838 invoked from network); 20 Nov 2001 07:55:30 -0000 Received: from unknown (HELO ocean.lucon.org) (24.176.137.160) by sourceware.cygnus.com with SMTP; 20 Nov 2001 07:55:30 -0000 Received: by ocean.lucon.org (Postfix, from userid 1000) id F1AFF125C3; Mon, 19 Nov 2001 23:55:29 -0800 (PST) Date: Wed, 07 Nov 2001 23:21:00 -0000 From: "H . J . Lu" To: Kevin Buettner Cc: gdb-patches@sources.redhat.com Subject: Re: [PATCH RFA] lin-lwp.c: Block SIGCHLD events when attaching Message-ID: <20011119235529.A20692@lucon.org> References: <1011119193045.ZM16376@ocotillo.lan> <20011119113832.A8778@lucon.org> <1011120004229.ZM17105@ocotillo.lan> <1011120022446.ZM17248@ocotillo.lan> <20011119185132.A16148@lucon.org> <1011120065319.ZM17495@ocotillo.lan> <1011120071710.ZM17562@ocotillo.lan> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="fdj2RfSjLxBAspz7" Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <1011120071710.ZM17562@ocotillo.lan>; from kevinb@cygnus.com on Tue, Nov 20, 2001 at 12:17:10AM -0700 X-SW-Source: 2001-11/txt/msg00144.txt.bz2 --fdj2RfSjLxBAspz7 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-length: 975 On Tue, Nov 20, 2001 at 12:17:10AM -0700, Kevin Buettner wrote: > On Nov 19, 11:53pm, Kevin Buettner wrote: > > > I just tried it. It seems to behave about the same. It usually attaches > > okay, but I am able to reproduce the "Cannot find new threads: generic error" > > by using Jim's trick of repeatedly attaching and detaching. > > I now know a little bit more about this problem. > > First, I should explain that I'm using Jim Blandy's trick of > > set height 0 > break > while 1 > attach > continue > detach > end > > The "Cannot find new threads: generic error" seems to occur just (or > shortly) after one of the early threads has exited. Tomorrow, I'll > write a test to see if it's possible at all to attach to a > multithreaded process in which one of the threads has exited. Here is a modified ex11.c. It is easier to reproduce the gdb bug. H.J. --fdj2RfSjLxBAspz7 Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename="ex11.c" Content-length: 3606 /* Test program for timedout read/write lock functions. Copyright (C) 2000 Free Software Foundation, Inc. Contributed by Ulrich Drepper , 2000. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more details. You should have received a copy of the GNU Library General Public License along with the GNU C Library; see the file COPYING.LIB. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include #include #include #include #include #include #include #define NWRITERS 15 #define WRITETRIES 10 #define NREADERS 15 #define READTRIES 15 #define TIMEOUT 1000000 #define DELAY 1000000 static pthread_rwlock_t lock = PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP; static void * writer_thread (void *nr) { struct timespec ts; struct timespec delay; int n; ts.tv_sec = 1000000; ts.tv_nsec = TIMEOUT; delay.tv_sec = 1000; delay.tv_nsec = DELAY; for (n = 0; n < WRITETRIES; ++n) { do { clock_gettime (CLOCK_REALTIME, &ts); ts.tv_nsec += 2 * TIMEOUT; // printf ("writer thread %ld tries again\n", (long int) nr); } //while (pthread_rwlock_wrlock (&lock), 0); while (pthread_rwlock_timedwrlock (&lock, &ts) == ETIMEDOUT); printf ("writer thread %ld succeeded\n", (long int) nr); nanosleep (&delay, NULL); pthread_rwlock_unlock (&lock); printf ("writer thread %ld released\n", (long int) nr); } return NULL; } static void * reader_thread (void *nr) { struct timespec ts; struct timespec delay; int n; delay.tv_sec = 1000000; delay.tv_nsec = DELAY; for (n = 0; n < READTRIES; ++n) { do { clock_gettime (CLOCK_REALTIME, &ts); ts.tv_nsec += TIMEOUT; // printf ("reader thread %ld tries again\n", (long int) nr); } //while (pthread_rwlock_rdlock (&lock), 0); while (pthread_rwlock_timedrdlock (&lock, &ts) == ETIMEDOUT); printf ("reader thread %ld succeeded\n", (long int) nr); nanosleep (&delay, NULL); pthread_rwlock_unlock (&lock); printf ("reader thread %ld released\n", (long int) nr); } return NULL; } int main (void) { pthread_t thwr[NWRITERS]; pthread_t thrd[NREADERS]; int n; void *res; /* Make standard error the same as standard output. */ dup2 (1, 2); /* Make sure we see all message, even those on stdout. */ setvbuf (stdout, NULL, _IONBF, 0); for (n = 0; n < NWRITERS; ++n) { int err = pthread_create (&thwr[n], NULL, writer_thread, (void *) (long int) n); if (err != 0) error (EXIT_FAILURE, err, "cannot create writer thread"); } for (n = 0; n < NREADERS; ++n) { int err = pthread_create (&thrd[n], NULL, reader_thread, (void *) (long int) n); if (err != 0) error (EXIT_FAILURE, err, "cannot create reader thread"); } /* Wait for all the threads. */ for (n = 0; n < NWRITERS; ++n) pthread_join (thwr[n], &res); for (n = 0; n < NREADERS; ++n) pthread_join (thrd[n], &res); return 0; } --fdj2RfSjLxBAspz7--