Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 1 Oct 2001 06:03:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 1 Oct 2001 06:03:31 -0400 Received: from balabit.bakats.tvnet.hu ([195.38.106.66]:46864 "EHLO kuka.balabit") by vger.kernel.org with ESMTP id ; Mon, 1 Oct 2001 06:03:23 -0400 Date: Mon, 1 Oct 2001 12:03:25 +0200 From: Balazs Scheidler To: Mark Hahn Cc: linux-kernel@vger.kernel.org Subject: Re: reproducible bug in 2.2.19 & 2.4.x Message-ID: <20011001120325.A7473@balabit.hu> In-Reply-To: <20010928203019.A24999@balabit.hu> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="k1lZvvs/B4yU6o8G" Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: ; from hahn@physics.mcmaster.ca on Fri, Sep 28, 2001 at 03:15:32PM -0400 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --k1lZvvs/B4yU6o8G Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Fri, Sep 28, 2001 at 03:15:32PM -0400, Mark Hahn wrote: > > seems like an interaction between your signal code and pthread, > no obvious reason to blame the kernel: I've updated my test program to address your issues: 1) I removed the SIGSEGV handler (you know with the fprintf()) 2) I modified it to use separate memory for all thread initialization data The segfault still occurs. (to reenable backtrace #define BACKTRACE to 1 at the beginning of the program) core is not dumped, because threaded programs do not drop core. I still think it's a kernel issue, at least the SMP dependancy tells me so. (remember SMP kernel on an UP is affected too) I also attach the strace of the process, which also shows the segfault. (it is made by strace 4.4 which can follow threads) PS: again please Cc me, since I'm not subscribed. -- Bazsi PGP info: KeyID 9AF8D0A9 Fingerprint CD27 CFB0 802C 0944 9CFD 804E C82C 8EB1 --k1lZvvs/B4yU6o8G Content-Type: text/x-csrc; charset=us-ascii Content-Disposition: attachment; filename="stressthreads.c" #include #include #include #include #include #include #include #include #include #define BACKTRACE 0 #if BACKTRACE void inline z_dump_backtrace(unsigned long eip, unsigned long first_ebp) { /* NOTE: this is i386 specific */ unsigned long *ebp; fprintf(stderr, "retaddr=0x%lx, ebp=0x%lx\n", eip, first_ebp); ebp = (unsigned long *) first_ebp; while (ebp > (unsigned long *) &ebp && *ebp) { fprintf(stderr, "retaddr=0x%lx, ebp=0x%lx\n", *(ebp+1), *ebp); ebp = (unsigned long *) *ebp; } } void z_fatal_signal_handler(int signo) { struct sigcontext *p = (struct sigcontext *) (((char *) &p) + 16); fprintf(stderr, "Signal (%d) received, stackdump follows; eax='%08lx', ebx='%08lx', ecx='%08lx', edx='%08lx', eip='%08lx'\n", signo, p->eax, p->ebx, p->ecx, p->edx, p->eip); z_dump_backtrace(p->eip, p->ebp); exit(1); } #endif void *thread_func(void *arg) { int fd = *(int *) arg; int i; char buf[1024]; syslog(LOG_DEBUG, "thread started...%p\n", pthread_self()); memset(buf, 'a', sizeof(buf)); for (i = 0; i < 1024; i++) { write(fd, buf, sizeof(buf)); } close(fd); //syslog(LOG_DEBUG, "thread stopped...%p\n", pthread_self()); free(arg); return NULL; } int main() { int fd; struct sockaddr_in sin; int tmp = 1; #if BACKTRACE signal(SIGSEGV, z_fatal_signal_handler); #endif signal(SIGPIPE, SIG_IGN); fd = socket(AF_INET, SOCK_STREAM, 0); sin.sin_family = AF_INET; sin.sin_port = htons(10000); sin.sin_addr.s_addr = INADDR_ANY; setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &tmp, sizeof(tmp)); if (bind(fd, (struct sockaddr *) &sin, sizeof(sin)) < 0) { perror("bind"); return 0; } listen(fd, 255); while (1) { int newfd; int tmplen; pthread_t t; tmplen = sizeof(sin); newfd = accept(fd, (struct sockaddr *) &sin, &tmplen); if (newfd == -1) { perror("accept"); } else { int *state = (int *) malloc(sizeof(int)); *state = newfd; pthread_create(&t, NULL, thread_func, state); } } } --k1lZvvs/B4yU6o8G-- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/