From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753981AbaD1Bax (ORCPT ); Sun, 27 Apr 2014 21:30:53 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:43109 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752922AbaD1B3Y (ORCPT ); Sun, 27 Apr 2014 21:29:24 -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, "Brian Norris" , "Artem Bityutskiy" , "Li Zefan" , "David Woodhouse" Date: Mon, 28 Apr 2014 02:11:22 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 42/94] jffs2: avoid soft-lockup in jffs2_reserve_space_gc() 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 3.2.58-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Li Zefan commit 13b546d96207c131eeae15dc7b26c6e7d0f1cad7 upstream. We triggered soft-lockup under stress test on 2.6.34 kernel. BUG: soft lockup - CPU#1 stuck for 60009ms! [lockf2.test:14488] ... [] (jffs2_do_reserve_space+0x420/0x440 [jffs2]) [] (jffs2_reserve_space_gc+0x34/0x78 [jffs2]) [] (jffs2_garbage_collect_dnode.isra.3+0x264/0x478 [jffs2]) [] (jffs2_garbage_collect_pass+0x9c0/0xe4c [jffs2]) [] (jffs2_reserve_space+0x104/0x2a8 [jffs2]) [] (jffs2_write_inode_range+0x5c/0x4d4 [jffs2]) [] (jffs2_write_end+0x198/0x2c0 [jffs2]) [] (generic_file_buffered_write+0x158/0x200) [] (__generic_file_aio_write+0x3a4/0x414) [] (generic_file_aio_write+0x5c/0xbc) [] (do_sync_write+0x98/0xd4) [] (vfs_write+0xa8/0x150) [] (sys_write+0x3c/0xc0)] Fix this by adding a cond_resched() in the while loop. [akpm@linux-foundation.org: don't initialize `ret'] Signed-off-by: Li Zefan Cc: David Woodhouse Cc: Artem Bityutskiy Signed-off-by: Andrew Morton Signed-off-by: Brian Norris [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- fs/jffs2/nodemgmt.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) --- a/fs/jffs2/nodemgmt.c +++ b/fs/jffs2/nodemgmt.c @@ -159,19 +159,24 @@ int jffs2_reserve_space(struct jffs2_sb_ int jffs2_reserve_space_gc(struct jffs2_sb_info *c, uint32_t minsize, uint32_t *len, uint32_t sumsize) { - int ret = -EAGAIN; + int ret; minsize = PAD(minsize); D1(printk(KERN_DEBUG "jffs2_reserve_space_gc(): Requested 0x%x bytes\n", minsize)); - spin_lock(&c->erase_completion_lock); - while(ret == -EAGAIN) { + while (true) { + spin_lock(&c->erase_completion_lock); ret = jffs2_do_reserve_space(c, minsize, len, sumsize); if (ret) { D1(printk(KERN_DEBUG "jffs2_reserve_space_gc: looping, ret is %d\n", ret)); } + spin_unlock(&c->erase_completion_lock); + + if (ret == -EAGAIN) + cond_resched(); + else + break; } - spin_unlock(&c->erase_completion_lock); if (!ret) ret = jffs2_prealloc_raw_node_refs(c, c->nextblock, 1);