From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 27 Aug 2007 13:33:47 -0700 From: Andrew Morton Subject: Re: [patch 1/1] alloc_pages(): permit get_zeroed_page(GFP_ATOMIC) from interrupt context Message-Id: <20070827133347.424f83a6.akpm@linux-foundation.org> In-Reply-To: References: <200708232107.l7NL7XDt026979@imap1.linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: linux-mm@kvack.org, thomas.jarosch@intra2net.com List-ID: On Mon, 27 Aug 2007 13:13:16 -0700 (PDT) Christoph Lameter wrote: > On Thu, 23 Aug 2007, akpm@linux-foundation.org wrote: > > > See http://bugzilla.kernel.org/show_bug.cgi?id=8928 > > > > I think it makes sense to permit a non-BUGging get_zeroed_page(GFP_ATOMIC) > > from interrupt context. > > AFAIK this works now. GFP_ATOMIC does not set __GFP_HIGHMEM and thus the > check > > VM_BUG_ON((gfp_flags & __GFP_HIGHMEM) && in_interrupt()); > > does not trigger The crash happens in clear_highpage ->kmap_atomic ->kmap_atomic_prot ->BUG_ON(!pte_none(*(kmap_pte-idx))); ie: this CPU held a kmap slot when the interrupt happened. -- 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