From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx132.postini.com [74.125.245.132]) by kanga.kvack.org (Postfix) with SMTP id EEF636B0044 for ; Tue, 1 May 2012 09:33:57 -0400 (EDT) Message-ID: <201205011333.q41DXsK7026759@farm-0013.internal.tilera.com> From: Chris Metcalf Date: Sun, 29 Apr 2012 15:04:51 -0400 Subject: Re: [PATCH] hugetlb: avoid gratuitous BUG_ON in hugetlb_fault() -> hugetlb_cow() In-Reply-To: <20120501131413.GA11435@suse.de> References: <201204291936.q3TJa4Mv008924@farm-0027.internal.tilera.com> <20120501131413.GA11435@suse.de> MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: Hugh Dickins Cc: Mel Gorman , Andrew Morton , Hillf Danton , Michal Hocko , KAMEZAWA Hiroyuki , linux-mm@kvack.org, linux-kernel@vger.kernel.org Commit 66aebce747eaf added code to avoid a race condition by elevating the page refcount in hugetlb_fault() while calling hugetlb_cow(). However, one code path in hugetlb_cow() includes an assertion that the page count is 1, whereas it may now also have the value 2 in this path. Consensus is that this BUG_ON has served its purpose, so rather than extending it to cover both cases, we just remove it. Signed-off-by: Chris Metcalf --- mm/hugetlb.c | 1 - 1 files changed, 0 insertions(+), 1 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index cd65cb1..baaad5d 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2498,7 +2498,6 @@ retry_avoidcopy: if (outside_reserve) { BUG_ON(huge_pte_none(pte)); if (unmap_ref_private(mm, vma, old_page, address)) { - BUG_ON(page_count(old_page) != 1); BUG_ON(huge_pte_none(pte)); spin_lock(&mm->page_table_lock); ptep = huge_pte_offset(mm, address & huge_page_mask(h)); -- 1.6.5.2 -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org