From patchwork Sun Apr 19 12:37:35 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KOSAKI Motohiro X-Patchwork-Id: 26179 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@bilbo.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from ozlabs.org (ozlabs.org [203.10.76.45]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "mx.ozlabs.org", Issuer "CA Cert Signing Authority" (verified OK)) by bilbo.ozlabs.org (Postfix) with ESMTPS id 7E8BEB6F35 for ; Sun, 19 Apr 2009 22:41:18 +1000 (EST) Received: by ozlabs.org (Postfix) id 700B3DE06B; Sun, 19 Apr 2009 22:41:18 +1000 (EST) Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by ozlabs.org (Postfix) with ESMTP id DA545DE067 for ; Sun, 19 Apr 2009 22:41:17 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760760AbZDSMkv (ORCPT ); Sun, 19 Apr 2009 08:40:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760475AbZDSMku (ORCPT ); Sun, 19 Apr 2009 08:40:50 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:57698 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759505AbZDSMkr (ORCPT ); Sun, 19 Apr 2009 08:40:47 -0400 Received: from m6.gw.fujitsu.co.jp ([10.0.50.76]) by fgwmail6.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id n3JCba61008370 (envelope-from kosaki.motohiro@jp.fujitsu.com); Sun, 19 Apr 2009 21:37:36 +0900 Received: from smail (m6 [127.0.0.1]) by outgoing.m6.gw.fujitsu.co.jp (Postfix) with ESMTP id 2227345DD6F; Sun, 19 Apr 2009 21:37:36 +0900 (JST) Received: from s6.gw.fujitsu.co.jp (s6.gw.fujitsu.co.jp [10.0.50.96]) by m6.gw.fujitsu.co.jp (Postfix) with ESMTP id 0415D45DD6E; Sun, 19 Apr 2009 21:37:36 +0900 (JST) Received: from s6.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s6.gw.fujitsu.co.jp (Postfix) with ESMTP id 0252A1DB8037; Sun, 19 Apr 2009 21:37:36 +0900 (JST) Received: from sw12.gw.fujitsu.co.jp (sw12.gw.fujitsu.co.jp [10.0.76.52]) by s6.gw.fujitsu.co.jp (Postfix) with ESMTP id A754C1DB803F; Sun, 19 Apr 2009 21:37:35 +0900 (JST) Received: from [127.0.0.1] ([172.31.140.141]) by sw12.gw.fujitsu.co.jp with ESMTP id n3JCbSnC004597; Sun, 19 Apr 2009 21:37:35 +0900 (JST) Date: Sun, 19 Apr 2009 21:37:35 +0900 (JST) From: KOSAKI Motohiro To: "Sosnowski, Maciej" Subject: Re: [RFC][PATCH v3 6/6] fix wrong get_user_pages usage in iovlock.c Cc: kosaki.motohiro@jp.fujitsu.com, Nick Piggin , LKML , Linus Torvalds , Andrew Morton , Andrea Arcangeli , Jeff Moyer , "linux-mm@kvack.org" , "linux-fsdevel@vger.kernel.org" , "David S. Miller" , "Leech, Christopher" , "netdev@vger.kernel.org" In-Reply-To: <129600E5E5FB004392DDC3FB599660D792A39DCE@irsmsx504.ger.corp.intel.com> References: <20090415174658.AC4F.A69D9226@jp.fujitsu.com> <129600E5E5FB004392DDC3FB599660D792A39DCE@irsmsx504.ger.corp.intel.com> Message-Id: <20090419202447.FFC2.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 X-Mailer: Becky! ver. 2.50 [ja] Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org > KOSAKI Motohiro wrote: > >>> I would perhaps not fold gup_fast conversions into the same patch as > >>> the fix. > >> > >> OK. I'll fix. > > > > Done. > > > > > > > > =================================== > > Subject: [Untested][RFC][PATCH] fix wrong get_user_pages usage in iovlock.c > > > > down_read(mmap_sem) > > get_user_pages() > > up_read(mmap_sem) > > > > is fork unsafe. > > fix it. > > > > Signed-off-by: KOSAKI Motohiro > > Cc: Maciej Sosnowski > > Cc: David S. Miller > > Cc: Chris Leech > > Cc: netdev@vger.kernel.org > > --- > > drivers/dma/iovlock.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > Index: b/drivers/dma/iovlock.c > > =================================================================== > > --- a/drivers/dma/iovlock.c 2009-04-13 22:58:36.000000000 +0900 > > +++ b/drivers/dma/iovlock.c 2009-04-14 20:27:16.000000000 +0900 > > @@ -104,8 +104,6 @@ struct dma_pinned_list *dma_pin_iovec_pa > > 0, /* force */ > > page_list->pages, > > NULL); > > - up_read(¤t->mm->mmap_sem); > > - > > if (ret != page_list->nr_pages) > > goto unpin; > > > > @@ -127,6 +125,8 @@ void dma_unpin_iovec_pages(struct dma_pi > > if (!pinned_list) > > return; > > > > + up_read(¤t->mm->mmap_sem); > > + > > for (i = 0; i < pinned_list->nr_iovecs; i++) { > > struct dma_page_list *page_list = &pinned_list->page_list[i]; > > for (j = 0; j < page_list->nr_pages; j++) { > > I have tried it with net_dma and here is what I've got. Thanks. Instead, How about this? --- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html ============================================ Subject: [Untested][RFC][PATCH v3] fix wrong get_user_pages usage in iovlock.c down_read(mmap_sem) get_user_pages() up_read(mmap_sem) is fork unsafe. mmap_sem should't be released until dma_unpin_iovec_pages() is called. Signed-off-by: KOSAKI Motohiro Cc: Maciej Sosnowski Cc: David S. Miller Cc: Chris Leech Cc: netdev@vger.kernel.org --- drivers/dma/iovlock.c | 5 ++--- net/ipv4/tcp.c | 9 +++++++++ 2 files changed, 11 insertions(+), 3 deletions(-) Index: b/drivers/dma/iovlock.c =================================================================== --- a/drivers/dma/iovlock.c 2009-04-19 17:27:25.000000000 +0900 +++ b/drivers/dma/iovlock.c 2009-04-19 17:29:42.000000000 +0900 @@ -45,6 +45,8 @@ static int num_pages_spanned(struct iove * We are allocating a single chunk of memory, and then carving it up into * 3 sections, the latter 2 whose size depends on the number of iovecs and the * total number of pages, respectively. + * + * Caller must hold mm->mmap_sem */ struct dma_pinned_list *dma_pin_iovec_pages(struct iovec *iov, size_t len) { @@ -94,7 +96,6 @@ struct dma_pinned_list *dma_pin_iovec_pa pages += page_list->nr_pages; /* pin pages down */ - down_read(¤t->mm->mmap_sem); ret = get_user_pages( current, current->mm, @@ -104,8 +105,6 @@ struct dma_pinned_list *dma_pin_iovec_pa 0, /* force */ page_list->pages, NULL); - up_read(¤t->mm->mmap_sem); - if (ret != page_list->nr_pages) goto unpin; Index: b/net/ipv4/tcp.c =================================================================== --- a/net/ipv4/tcp.c 2009-04-19 17:27:25.000000000 +0900 +++ b/net/ipv4/tcp.c 2009-04-19 18:09:42.000000000 +0900 @@ -1322,6 +1322,9 @@ int tcp_recvmsg(struct kiocb *iocb, stru int copied_early = 0; struct sk_buff *skb; +#ifdef CONFIG_NET_DMA + down_read(¤t->mm->mmap_sem); +#endif lock_sock(sk); TCP_CHECK_TIMER(sk); @@ -1688,11 +1691,17 @@ skip_copy: TCP_CHECK_TIMER(sk); release_sock(sk); +#ifdef CONFIG_NET_DMA + up_read(¤t->mm->mmap_sem); +#endif return copied; out: TCP_CHECK_TIMER(sk); release_sock(sk); +#ifdef CONFIG_NET_DMA + up_read(¤t->mm->mmap_sem); +#endif return err; recv_urg: