From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sun, 19 Oct 2008 10:52:46 +0100 (BST) From: Hugh Dickins Subject: Re: [patch] mm: fix anon_vma races In-Reply-To: <1224326299.28131.132.camel@twins> Message-ID: References: <20081016041033.GB10371@wotan.suse.de> <1224285222.10548.22.camel@lappy.programming.kicks-ass.net> <20081018013258.GA3595@wotan.suse.de> <20081018022541.GA19018@wotan.suse.de> <20081018052046.GA26472@wotan.suse.de> <1224326299.28131.132.camel@twins> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Peter Zijlstra Cc: Nick Piggin , Linus Torvalds , Linux Memory Management List List-ID: On Sat, 18 Oct 2008, Peter Zijlstra wrote: > > fault_creation: > > anon_vma_prepare() > page_add_new_anon_rmap(); > > expand_creation: > > anon_vma_prepare() > anon_vma_lock(); > > rmap_lookup: > > page_referenced()/try_to_unmap() > page_lock_anon_vma() > > vma_lookup: > > vma_adjust()/vma_* > vma->anon_vma > > teardown: > > unmap_vmas() > zap_range() > page_remove_rmap() > free_page() > free_pgtables() > anon_vma_unlink() > free_range() > > IOW we remove rmap, free the page (set mapping=NULL) and then unlink and > free the anon_vma. > > But at that time vma->anon_vma is still set. > > > head starts to hurt,.. Comprehension isn't my strong suit at the moment: I don't grasp what problem you're seeing here - if you can spell it out in more detail for me, I'd like to try stopping your head hurt - though not at cost of making mine hurt more! 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