From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 1 Aug 2005 20:29:40 +0100 (BST) From: Hugh Dickins Subject: Re: [patch 2.6.13-rc4] fix get_user_pages bug In-Reply-To: Message-ID: References: <20050801032258.A465C180EC0@magilla.sf.frob.com> <42EDDB82.1040900@yahoo.com.au> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Linus Torvalds Cc: Nick Piggin , Robin Holt , Andrew Morton , Roland McGrath , Martin Schwidefsky , linux-mm@kvack.org, linux-kernel List-ID: On Mon, 1 Aug 2005, Linus Torvalds wrote: > > that "continue" will continue without the spinlock held, and now do Yes, I was at last about to reply on that point and others. I'll make those comments in a separate mail to Nick and all. > Instead, I'd suggest changing the logic for "lookup_write". Make it > require that the page table entry is _dirty_ (not writable), and then Attractive, I very much wanted to do that rather than change all the arches, but I think s390 rules it out: its pte_mkdirty does nothing, its pte_dirty just says no. Whether your patch suits all other uses of (__)follow_page I've not investigated (and I don't see how you can go without the set_page_dirty if it was necessary before); but at present see no alternative to something like Nick's patch, though I'd much prefer smaller. Or should we change s390 to set a flag in the pte just for this purpose? Hugh -- 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