From owner-freebsd-emulation@FreeBSD.ORG Mon Feb 11 16:37:38 2008 Return-Path: Delivered-To: freebsd-emulation@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 20D6C16A420 for ; Mon, 11 Feb 2008 16:37:38 +0000 (UTC) (envelope-from avg@icyb.net.ua) Received: from falcon.cybervisiontech.com (falcon.cybervisiontech.com [217.20.163.9]) by mx1.freebsd.org (Postfix) with ESMTP id 9381A13C4D5 for ; Mon, 11 Feb 2008 16:37:37 +0000 (UTC) (envelope-from avg@icyb.net.ua) Received: from localhost (localhost [127.0.0.1]) by falcon.cybervisiontech.com (Postfix) with ESMTP id 981C143C927 for ; Mon, 11 Feb 2008 18:16:22 +0200 (EET) X-Virus-Scanned: Debian amavisd-new at falcon.cybervisiontech.com Received: from falcon.cybervisiontech.com ([127.0.0.1]) by localhost (falcon.cybervisiontech.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id eEPVfT54Dfbc for ; Mon, 11 Feb 2008 18:16:22 +0200 (EET) Received: from [10.2.1.87] (gateway.cybervisiontech.com.ua [88.81.251.18]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by falcon.cybervisiontech.com (Postfix) with ESMTP id 4E88543C90B for ; Mon, 11 Feb 2008 18:16:22 +0200 (EET) Message-ID: <47B074D5.1020602@icyb.net.ua> Date: Mon, 11 Feb 2008 18:16:21 +0200 From: Andriy Gapon User-Agent: Thunderbird 2.0.0.9 (X11/20080123) MIME-Version: 1.0 To: freebsd-emulation@freebsd.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: bug in recent linux mmap changes ? X-BeenThere: freebsd-emulation@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Development of Emulators of other operating systems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 11 Feb 2008 16:37:38 -0000 After upgrading two machines, one to 6.3 and the other to 7.0-RC1, I can not run linux heroes3 anymore (statically linked, threaded application originally written for kernel 2.2.X). On 6.3 the process "hangs", on 7.0-RC1 one of the threads/processes crashes with SIGSEGV. Everything was OK as recently as 6.2. I can provide more diagnostics later, if needed, but in both cases I see that the last system call in a troublesome thread/process is linux_mmap(). I did a brief search through recent linux_mmap changes and I think that there is a bug in the following commit (I am writing this hastiliy, so I haven't yet tested a possible fix): http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/i386/linux/linux_machdep.c.diff?r1=1.48.2.4;r2=1.48.2.5;f=h Namely, old code: ==================================================== /* This gives us TOS */ bsd_args.addr = linux_args->addr + linux_args->len; if (bsd_args.addr > p->p_vmspace->vm_maxsaddr) { [block folded] } /* This gives us our maximum stack size */ if (linux_args->len > STACK_SIZE - GUARD_SIZE) bsd_args.len = linux_args->len; else bsd_args.len = STACK_SIZE - GUARD_SIZE; /* [comment folded] */ bsd_args.addr -= bsd_args.len; ==================================================== New code: ==================================================== if ((caddr_t)PTRIN(linux_args->addr) + linux_args->len > p->p_vmspace->vm_maxsaddr) { [block folded] } /* This gives us our maximum stack size */ if (linux_args->len > STACK_SIZE - GUARD_SIZE) bsd_args.len = linux_args->len; else bsd_args.len = STACK_SIZE - GUARD_SIZE; /* [comment foled] */ bsd_args.addr = (caddr_t)PTRIN(linux_args->addr) - bsd_args.len; ==================================================== Please now note that the new code doesn't have initial bsd_args.addr assignment line. So, in summary, old code does the following: bsd_args.addr = linux_args->addr + linux_args->len; ... bsd_args.addr -= bsd_args.len; While new code does: bsd_args.addr = (caddr_t)PTRIN(linux_args->addr) - bsd_args.len; -- Andriy Gapon