Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751155AbXBOA34 (ORCPT ); Wed, 14 Feb 2007 19:29:56 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751412AbXBOA34 (ORCPT ); Wed, 14 Feb 2007 19:29:56 -0500 Received: from saraswathi.solana.com ([198.99.130.12]:34467 "EHLO saraswathi.solana.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751407AbXBOA3z (ORCPT ); Wed, 14 Feb 2007 19:29:55 -0500 Date: Wed, 14 Feb 2007 19:22:05 -0500 From: Jeff Dike To: Miklos Szeredi Cc: linux-kernel@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net Subject: Re: [uml-devel] UML hang with 100% CPU Message-ID: <20070215002205.GA8099@ccure.user-mode-linux.org> References: <20070208195711.GA6607@ccure.user-mode-linux.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2598 Lines: 95 On Thu, Feb 08, 2007 at 09:13:36PM +0100, Miklos Szeredi wrote: > Strangely enough after continuing in gdb, UML is back to normal, and I > can't make it hang any more. It must be something timing related. Can you see if the patch below fixes it? Jeff -- Work email - jdike at linux dot intel dot com Index: linux-2.6.18-mm/arch/um/os-Linux/sigio.c =================================================================== --- linux-2.6.18-mm.orig/arch/um/os-Linux/sigio.c 2007-02-08 16:48:00.000000000 -0500 +++ linux-2.6.18-mm/arch/um/os-Linux/sigio.c 2007-02-14 19:16:22.000000000 -0500 @@ -97,20 +97,22 @@ static int write_sigio_thread(void *unus static int need_poll(struct pollfds *polls, int n) { - if(n <= polls->size){ - polls->used = n; + struct pollfd *new; + + if(n <= polls->size) return 0; - } - kfree(polls->poll); - polls->poll = um_kmalloc_atomic(n * sizeof(struct pollfd)); - if(polls->poll == NULL){ + + new = um_kmalloc_atomic(n * sizeof(struct pollfd)); + if(new == NULL){ printk("need_poll : failed to allocate new pollfds\n"); - polls->size = 0; - polls->used = 0; return -ENOMEM; } + + memcpy(new, polls->poll, polls->used * sizeof(struct pollfd)); + kfree(polls->poll); + + polls->poll = new; polls->size = n; - polls->used = n; return 0; } @@ -171,15 +173,15 @@ int add_sigio_fd(int fd) goto out; } - n = current_poll.used + 1; - err = need_poll(&next_poll, n); + n = current_poll.used; + err = need_poll(&next_poll, n + 1); if(err) goto out; - for(i = 0; i < current_poll.used; i++) - next_poll.poll[i] = current_poll.poll[i]; - - next_poll.poll[n - 1] = *p; + memcpy(next_poll.poll, current_poll.poll, + current_poll.used * sizeof(struct pollfd)); + next_poll.poll[n] = *p; + next_poll.used = n + 1; update_thread(); out: sigio_unlock(); @@ -214,6 +216,7 @@ int ignore_sigio_fd(int fd) if(p->fd != fd) next_poll.poll[n++] = *p; } + next_poll.used = current_poll.used - 1; update_thread(); out: @@ -331,10 +334,9 @@ void maybe_sigio_broken(int fd, int read sigio_lock(); err = need_poll(&all_sigio_fds, all_sigio_fds.used + 1); - if(err){ - printk("maybe_sigio_broken - failed to add pollfd\n"); + if(err) goto out; - } + all_sigio_fds.poll[all_sigio_fds.used++] = ((struct pollfd) { .fd = fd, .events = read ? POLLIN : POLLOUT, - 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/