From owner-cvs-all Wed Apr 18 12:28:30 2001 Delivered-To: cvs-all@freebsd.org Received: from meow.osd.bsdi.com (meow.osd.bsdi.com [204.216.28.88]) by hub.freebsd.org (Postfix) with ESMTP id C634C37B423; Wed, 18 Apr 2001 12:28:24 -0700 (PDT) (envelope-from jhb@FreeBSD.org) Received: from laptop.baldwin.cx (john@jhb-laptop.osd.bsdi.com [204.216.28.241]) by meow.osd.bsdi.com (8.11.2/8.11.2) with ESMTP id f3IJS5G55381; Wed, 18 Apr 2001 12:28:05 -0700 (PDT) (envelope-from jhb@FreeBSD.org) Message-ID: X-Mailer: XFMail 1.4.0 on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: Date: Wed, 18 Apr 2001 12:27:28 -0700 (PDT) From: John Baldwin To: Doug Rabson Subject: Re: cvs commit: src/sys/alpha/alpha exception.s Cc: cvs-all@FreeBSD.org, cvs-committers@FreeBSD.org Sender: owner-cvs-all@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On 18-Apr-01 Doug Rabson wrote: > On Wed, 18 Apr 2001, John Baldwin wrote: > >> jhb 2001/04/18 10:17:55 PDT >> >> Modified files: >> sys/alpha/alpha exception.s >> Log: >> Back out the previous revision as it causes random sig 11's to userland >> processes until a better fix is found. > > I can see several possible races here. For instance, if an interrupt > happened partway through restoring registers trying to return to userland, > we could corrupt the user's t7 pretty easily. > > I can't quite think of the correct solution yet though. Oh, we share the same stack frame for user and kernel returns? Oh yuck. I can hack around that by raising the IPL in Lkernelret before changing t7, but if we use the same stackframe how do interrupts in the kernel work at all w/o trashing the user frame? -- John Baldwin -- http://www.FreeBSD.org/~jhb/ PGP Key: http://www.baldwin.cx/~john/pgpkey.asc "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message