From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:9006 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752555AbaKXA1d (ORCPT ); Sun, 23 Nov 2014 19:27:33 -0500 Date: Sun, 23 Nov 2014 19:27:23 -0500 From: Chris Mason Subject: Re: [GIT PULL] Btrfs deadlock fix To: Benjamin Herrenschmidt CC: , , Message-ID: <1416788843.3019.2@mail.thefacebook.com> In-Reply-To: <1416788595.4998.5.camel@kernel.crashing.org> References: <20141123151439.GA16816@ret.masoncoding.com> <1416788595.4998.5.camel@kernel.crashing.org> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Sun, Nov 23, 2014 at 7:23 PM, Benjamin Herrenschmidt wrote: > On Sun, 2014-11-23 at 10:14 -0500, Chris Mason wrote: >> Hi Linus, >> >> My for-linus branch: > > Not sure if this is related, but with -rc4, on this ppc64el box, when > grub updates (it starts trying to mount everything under the sun with > every filesystem), the box hangs with: > > [ 177.344522] INFO: rcu_sched detected stalls on CPUs/tasks: { 8} > (detected by 9, t=25883 jiffies, g=3642, c=3641, q=5206) > > With xmon I can catch it with this backtrace: > > [link register ] d00000000ecec3f8 test_check_exists+0x1f8/0x280 > [btrfs] > [c000000f0cc63930] d00000000ecec2b0 test_check_exists+0xb0/0x280 > [btrfs] (unreliable) > [c000000f0cc63990] d00000000ed2a4b4 > btrfs_test_free_space_cache+0x774/0x1150 [btrfs] > [c000000f0cc63a20] d00000000ed30f04 init_btrfs_fs+0x11c/0x210 [btrfs] > [c000000f0cc63a90] c00000000000b4dc do_one_initcall+0x12c/0x280 > [c000000f0cc63b60] c0000000001628b8 load_module+0x2088/0x2970 > [c000000f0cc63d50] c0000000001633d0 SyS_finit_module+0xc0/0x120 > [c000000f0cc63e30] c00000000000927c syscall_exit+0x0/0x7c > --- Exception: c01 (System Call) at 00003fff88697184 > > Note that afaik there isn't any btrfs partition on any disk on that > machine... well not that I know of :) This should be from CONFIG_BTRFS_FS_RUN_SANITY_TESTS=y. I do test with this on here, but I'll look it over for ppc related fun. The deadlock fix from this pull shouldn't be related. Just to make sure I read your email right, this stall isn't new with rc6 is it? -chris