Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754627AbZDNG6Z (ORCPT ); Tue, 14 Apr 2009 02:58:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751658AbZDNG6H (ORCPT ); Tue, 14 Apr 2009 02:58:07 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:42808 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751512AbZDNG6E (ORCPT ); Tue, 14 Apr 2009 02:58:04 -0400 From: KOSAKI Motohiro To: Nick Piggin Subject: Re: [RFC][PATCH v3 6/6] fix wrong get_user_pages usage in iovlock.c Cc: kosaki.motohiro@jp.fujitsu.com, LKML , Linus Torvalds , Andrew Morton , Andrea Arcangeli , Jeff Moyer , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Maciej Sosnowski , "David S. Miller" , Chris Leech , netdev@vger.kernel.org In-Reply-To: <200904141656.14191.nickpiggin@yahoo.com.au> References: <20090414152151.C659.A69D9226@jp.fujitsu.com> <200904141656.14191.nickpiggin@yahoo.com.au> Message-Id: <20090414155719.C66B.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.50 [ja] Date: Tue, 14 Apr 2009 15:58:00 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1947 Lines: 58 > On Tuesday 14 April 2009 16:23:13 KOSAKI Motohiro wrote: > > I don't have NET-DMA usable device. I hope to get expert review. > > > > ========================= > > 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 | 18 ++++++------------ > > 1 file changed, 6 insertions(+), 12 deletions(-) > > > > Index: b/drivers/dma/iovlock.c > > =================================================================== > > --- a/drivers/dma/iovlock.c 2009-02-21 16:53:23.000000000 +0900 > > +++ b/drivers/dma/iovlock.c 2009-04-13 04:46:02.000000000 +0900 > > @@ -94,18 +94,10 @@ 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, > > - (unsigned long) iov[i].iov_base, > > - page_list->nr_pages, > > - 1, /* write */ > > - 0, /* force */ > > - page_list->pages, > > - NULL); > > - up_read(¤t->mm->mmap_sem); > > - > > + down_read(¤t->mm->mm_pinned_sem); > > + ret = get_user_pages_fast((unsigned long) iov[i].iov_base, > > + page_list->nr_pages, 1, > > + page_list->pages); > > I would perhaps not fold gup_fast conversions into the same patch as > the fix. OK. I'll fix. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/