From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 28 Sep 2007 21:30:18 +0200 From: Jens Axboe Subject: Re: [patch] splice mmap_sem deadlock Message-ID: <20070928193017.GC11717@kernel.dk> References: <20070928160035.GD12538@wotan.suse.de> <20070928173144.GA11717@kernel.dk> <20070928181513.GB11717@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org Return-Path: To: Linus Torvalds Cc: Nick Piggin , Andrew Morton , Linux Memory Management List List-ID: On Fri, Sep 28 2007, Linus Torvalds wrote: > > > On Fri, 28 Sep 2007, Jens Axboe wrote: > > > > It actually looks like it was buggy from day 1 there, unfortunately. The > > code is from april 2006 and used down_read() even then. > > I was thinking of my *original* patch from way back when. But that one > didn't actually do any of that stuff so no, it wasn't from there. Right, vmsplice() wasn't part of the original stuff. > > So can you apply Nicks patch > > I don't even have it, I only have a quoted-corrupted version of it. I > wasn't originally cc'd. Hmm, part of me doesn't like this patch, since we now end up beating on mmap_sem for each part of the vec. It's fine for a stable patch, but how about - prefaulting the iovec - using __get_user() - only dropping/regrabbing the lock if we have to fault ? -- Jens Axboe -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org