From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with SMTP id 50DAB5F0001 for ; Tue, 14 Apr 2009 02:22:58 -0400 (EDT) Received: from mt1.gw.fujitsu.co.jp ([10.0.50.74]) by fgwmail7.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id n3E6NIGX021827 for (envelope-from kosaki.motohiro@jp.fujitsu.com); Tue, 14 Apr 2009 15:23:18 +0900 Received: from smail (m4 [127.0.0.1]) by outgoing.m4.gw.fujitsu.co.jp (Postfix) with ESMTP id 2FF8E45DE4E for ; Tue, 14 Apr 2009 15:23:18 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (s4.gw.fujitsu.co.jp [10.0.50.94]) by m4.gw.fujitsu.co.jp (Postfix) with ESMTP id 0F36345DE53 for ; Tue, 14 Apr 2009 15:23:18 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id C4E86E08003 for ; Tue, 14 Apr 2009 15:23:17 +0900 (JST) Received: from ml14.s.css.fujitsu.com (ml14.s.css.fujitsu.com [10.249.87.104]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 7A76F1DB803E for ; Tue, 14 Apr 2009 15:23:14 +0900 (JST) From: KOSAKI Motohiro Subject: [RFC][PATCH v3 6/6] fix wrong get_user_pages usage in iovlock.c 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 Date: Tue, 14 Apr 2009 15:23:13 +0900 (JST) Sender: owner-linux-mm@kvack.org To: LKML 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 List-ID: 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, 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