From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753562AbYGEBxe (ORCPT ); Fri, 4 Jul 2008 21:53:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751732AbYGEBx0 (ORCPT ); Fri, 4 Jul 2008 21:53:26 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:35853 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751714AbYGEBxZ (ORCPT ); Fri, 4 Jul 2008 21:53:25 -0400 Date: Fri, 4 Jul 2008 18:53:12 -0700 From: Andrew Morton To: "Alexey Dobriyan" Cc: torvalds@linuxfoundation.org, akpm@linuxfoundation.org, mpm@selenic.com, linux-kernel@vger.kernel.org Subject: Re: *sigh* /proc/*/pagemap Message-Id: <20080704185312.052e7145.akpm@linux-foundation.org> In-Reply-To: References: X-Mailer: Sylpheed 2.4.8 (GTK+ 2.12.5; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 5 Jul 2008 05:07:02 +0400 "Alexey Dobriyan" wrote: > I'm few days from my patch-sending facility, but could someone > _please_ do the following before release: > > 1) initialize pagemap_walk.mm to "mm" , so the code starts working as > advertised, and > 2) also initialize ->private to "&pm" so it wouldn't immediately oops > in pagemap_pte_hole(), and Geeze you're picky! If everyone was like you we wouldn't need that nice oops-printing code. > 3) unstatic struct pagemap_walk, so two threads won't fsckup each other > (including those started by root, including flipping ->mm when you > don't have permissions), Below > and > 4) remove second ptrace_may_attach(), and Can't find what you're referring to here. > 5) check with microscope allocation there -- page-aligned address and size == 0 > should allocate 0 bytes, and Where? > 6) actually check that it works. Will have a shot. From: Andrew Morton - initialize pagemap_walk.mm to "mm" , so the code starts working as advertised - initialize ->private to "&pm" so it wouldn't immediately oops in pagemap_pte_hole() - unstatic struct pagemap_walk, so two threads won't fsckup each other (including those started by root, including flipping ->mm when you don't have permissions) Signed-off-by: Andrew Morton --- fs/proc/task_mmu.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff -puN fs/proc/task_mmu.c~pagemap-fixes-to-pagemap_read fs/proc/task_mmu.c --- a/fs/proc/task_mmu.c~pagemap-fixes-to-pagemap_read +++ a/fs/proc/task_mmu.c @@ -602,11 +602,6 @@ static int pagemap_pte_range(pmd_t *pmd, return err; } -static struct mm_walk pagemap_walk = { - .pmd_entry = pagemap_pte_range, - .pte_hole = pagemap_pte_hole -}; - /* * /proc/pid/pagemap - an array mapping virtual pages to pfns * @@ -641,6 +636,7 @@ static ssize_t pagemap_read(struct file struct pagemapread pm; int pagecount; int ret = -ESRCH; + static struct mm_walk pagemap_walk; if (!task) goto out; @@ -659,6 +655,7 @@ static ssize_t pagemap_read(struct file if (!mm) goto out_task; + ret = -ENOMEM; uaddr = (unsigned long)buf & PAGE_MASK; uend = (unsigned long)(buf + count); @@ -684,6 +681,11 @@ static ssize_t pagemap_read(struct file pm.out = (u64 *)buf; pm.end = (u64 *)(buf + count); + pagemap_walk.pmd_entry = pagemap_pte_range; + pagemap_walk.pte_hole = pagemap_pte_hole; + pagemap_walk.mm = mm; + pagemap_walk.private = ± + if (!ptrace_may_attach(task)) { ret = -EIO; } else { _