Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754922AbZDNGXl (ORCPT ); Tue, 14 Apr 2009 02:23:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754034AbZDNGXS (ORCPT ); Tue, 14 Apr 2009 02:23:18 -0400 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:56159 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753626AbZDNGXQ (ORCPT ); Tue, 14 Apr 2009 02:23:16 -0400 From: KOSAKI Motohiro To: LKML Subject: [RFC][PATCH v3 6/6] fix wrong get_user_pages usage in iovlock.c Cc: kosaki.motohiro@jp.fujitsu.com, Linus Torvalds , Andrew Morton , Nick Piggin , 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: <20090414151204.C647.A69D9226@jp.fujitsu.com> References: <20090414151204.C647.A69D9226@jp.fujitsu.com> Message-Id: <20090414152151.C659.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 15:23:13 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1958 Lines: 64 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); if (ret != page_list->nr_pages) goto unpin; @@ -127,6 +119,8 @@ void dma_unpin_iovec_pages(struct dma_pi if (!pinned_list) return; + up_read(¤t->mm->mm_pinned_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++) { -- 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/