From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [213.86.99.237] (helo=passion.cambridge.redhat.com) by pentafluge.infradead.org with esmtp (Exim 3.22 #1 (Red Hat Linux)) id 18bdVO-0006nK-00 for ; Thu, 23 Jan 2003 09:18:39 +0000 From: David Woodhouse In-Reply-To: <000001c2c287$ffa8eef0$800b040f@bergamot> References: <000001c2c287$ffa8eef0$800b040f@bergamot> To: "Christopher Hoover" Cc: "'Frank Becker'" , linux-arm-kernel@lists.arm.linux.org.uk, "'linux-mtd'" , akpm@digeo.com, linux-kernel@vger.kernel.org Subject: Re: 2.5.55-rmk1: user space lossage Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Thu, 23 Jan 2003 09:48:23 +0000 Message-ID: <15943.1043315303@passion.cambridge.redhat.com> Sender: linux-mtd-admin@lists.infradead.org Errors-To: linux-mtd-admin@lists.infradead.org List-Help: List-Post: List-Subscribe: , List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: < Snip long thread about init segfaulting immediately at boot on 2.5.55 > ch@murgatroid.com said: > I just dropped jffs2 from 2.5.52 into 2.5.55 and it works, too. ch@murgatroid.com said: > Aha! This is the problem: > - .mmap = generic_file_mmap, > + .mmap = generic_file_readonly_mmap, > If you reverese this change, 2.5.55-rmk1 behaves. Er, yes. generic_file_readonly_mmap() silently removed the VM_MAYWRITE bit from vma->vm_flags when init made a _PRIVATE_ writable mapping, apparently on the basis that we have no writepage(). Then we return success anyway. Then init segfaults when it touches something in that mapping. /me blames akpm. :) -- dwmw2