Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752890AbaFEEVJ (ORCPT ); Thu, 5 Jun 2014 00:21:09 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:44032 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752830AbaFEEVE (ORCPT ); Thu, 5 Jun 2014 00:21:04 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jerome Marchand , Nitin Gupta , Pekka Enberg , Minchan Kim , Ben Hutchings , Jianguo Wu Subject: [PATCH 3.4 102/214] zram: Fix deadlock bug in partial read/write Date: Wed, 4 Jun 2014 21:17:45 -0700 Message-Id: <20140605041653.411654637@linuxfoundation.org> X-Mailer: git-send-email 2.0.0 In-Reply-To: <20140605041639.638675216@linuxfoundation.org> References: <20140605041639.638675216@linuxfoundation.org> User-Agent: quilt/0.60-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Minchan Kim commit 7e5a5104c6af709a8d97d5f4711e7c917761d464 upstream. Now zram allocates new page with GFP_KERNEL in zram I/O path if IO is partial. Unfortunately, It may cause deadlock with reclaim path like below. write_page from fs fs_lock allocation(GFP_KERNEL) reclaim pageout write_page from fs fs_lock <-- deadlock This patch fixes it by using GFP_NOIO. In read path, we reorganize code flow so that kmap_atomic is called after the GFP_NOIO allocation. Acked-by: Jerome Marchand Acked-by: Nitin Gupta [ penberg@kernel.org: don't use GFP_ATOMIC ] Signed-off-by: Pekka Enberg Signed-off-by: Minchan Kim Signed-off-by: Greg Kroah-Hartman [bwh: Backported to 3.2: no reordering is needed in the read path] Signed-off-by: Ben Hutchings Cc: Jianguo Wu Signed-off-by: Greg Kroah-Hartman --- drivers/staging/zram/zram_drv.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/staging/zram/zram_drv.c +++ b/drivers/staging/zram/zram_drv.c @@ -235,7 +235,7 @@ static int zram_bvec_read(struct zram *z if (is_partial_io(bvec)) { /* Use a temporary buffer to decompress the page */ - uncmem = kmalloc(PAGE_SIZE, GFP_KERNEL); + uncmem = kmalloc(PAGE_SIZE, GFP_NOIO); if (!uncmem) { pr_info("Error allocating temp memory!\n"); return -ENOMEM; @@ -330,7 +330,7 @@ static int zram_bvec_write(struct zram * * This is a partial IO. We need to read the full page * before to write the changes. */ - uncmem = kmalloc(PAGE_SIZE, GFP_KERNEL); + uncmem = kmalloc(PAGE_SIZE, GFP_NOIO); if (!uncmem) { pr_info("Error allocating temp memory!\n"); ret = -ENOMEM; -- 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/