From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754007AbaCaAku (ORCPT ); Sun, 30 Mar 2014 20:40:50 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:37641 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753890AbaCaAkq (ORCPT ); Sun, 30 Mar 2014 20:40:46 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Linus Torvalds" , "KOSAKI Motohiro" , David Rientjes Date: Mon, 31 Mar 2014 00:23:35 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 091/200] mm: __set_page_dirty uses spin_lock_irqsave instead of spin_lock_irq In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.249 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.56-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: KOSAKI Motohiro commit 227d53b397a32a7614667b3ecaf1d89902fb6c12 upstream. To use spin_{un}lock_irq is dangerous if caller disabled interrupt. During aio buffer migration, we have a possibility to see the following call stack. aio_migratepage [disable interrupt] migrate_page_copy clear_page_dirty_for_io set_page_dirty __set_page_dirty_buffers __set_page_dirty spin_lock_irq This mean, current aio migration is a deadlockable. spin_lock_irqsave is a safer alternative and we should use it. Signed-off-by: KOSAKI Motohiro Reported-by: David Rientjes rientjes@google.com> Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings --- fs/buffer.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/fs/buffer.c +++ b/fs/buffer.c @@ -663,14 +663,16 @@ EXPORT_SYMBOL(mark_buffer_dirty_inode); static void __set_page_dirty(struct page *page, struct address_space *mapping, int warn) { - spin_lock_irq(&mapping->tree_lock); + unsigned long flags; + + spin_lock_irqsave(&mapping->tree_lock, flags); if (page->mapping) { /* Race with truncate? */ WARN_ON_ONCE(warn && !PageUptodate(page)); account_page_dirtied(page, mapping); radix_tree_tag_set(&mapping->page_tree, page_index(page), PAGECACHE_TAG_DIRTY); } - spin_unlock_irq(&mapping->tree_lock); + spin_unlock_irqrestore(&mapping->tree_lock, flags); __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); }