From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kara Subject: Re: new kernel warning when running xfstest ext4/271 on 3.12 Date: Tue, 15 Oct 2013 15:12:33 +0200 Message-ID: <20131015131233.GD12428@quack.suse.cz> References: <20131014021606.GA31336@wallace> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4@vger.kernel.org To: Eric Whitney Return-path: Received: from cantor2.suse.de ([195.135.220.15]:45976 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758579Ab3JONMg (ORCPT ); Tue, 15 Oct 2013 09:12:36 -0400 Content-Disposition: inline In-Reply-To: <20131014021606.GA31336@wallace> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Sun 13-10-13 22:16:06, Eric Whitney wrote: > Since 3.12-rc1, I've noticed a new warning message in my kernel logs when > running ext4 regression tests with xfstests on both my x86-64 (KVM guest) and > ARM (Pandaboard ES) SUTs. (I'm using xfstests-bld to run xfstests.) It > remains visible in 3.12-rc4. > > The warning appears when running ext4/271 after mounting the test file system > with the dioread_nolock option. > > After running ext4/271, the kernel log contains the following trace repeated > 21 times, apparently once for each write performed by dd in the test: > > EXT4-fs (vdc): mounted filesystem without journal. Opts: dioread_nolock,noload Ah, OK. Unusual combination of mount options about which I didn't think when writing the assertion :) The warning is false positive - in nojournal mode it doesn't make sense to ask for a reserved handle. I'll send a fix to silence the warning. Thanks for report! Honza > ------------[ cut here ]------------ > WARNING: CPU: 1 PID: 1366 at fs/ext4/page-io.c:205 ext4_put_io_end_defer+0xf5/0x100() > Modules linked in: snd_hda_intel snd_hda_codec snd_hwdep snd_pcm snd_timer psmouse serio_raw snd soundcore virtio_balloon snd_page_alloc i2c_piix4 mac_hid lp parport floppy > CPU: 1 PID: 1366 Comm: dd Not tainted 3.12.0-rc4-ext4testing+ #1 > Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 > 0000000000000009 ffff88003fd03d10 ffffffff816e3b66 0000000000000000 > ffff88003fd03d48 ffffffff8104eb4c ffff88003d1a1168 ffff88003d209c10 > 0000000000000000 0000000000001000 ffff88003bb57490 ffff88003fd03d58 > Call Trace: > [] dump_stack+0x45/0x56 > [] warn_slowpath_common+0x8c/0xc0 > [] warn_slowpath_null+0x1a/0x20 > [] ext4_put_io_end_defer+0xf5/0x100 > [] ext4_end_bio+0xc6/0xe0 > [] bio_endio+0x1d/0x30 > [] blk_update_request+0xba/0x450 > [] ? blk_update_request+0x360/0x450 > [] blk_update_bidi_request+0x27/0xa0 > [] __blk_end_bidi_request+0x20/0x50 > [] __blk_end_request_all+0x1f/0x30 > [] virtblk_done+0x100/0x260 > [] vring_interrupt+0x31/0x50 > [] handle_irq_event_percpu+0x54/0x1f0 > [] handle_irq_event+0x48/0x70 > [] handle_edge_irq+0x77/0x110 > [] handle_irq+0x1e/0x30 > [] do_IRQ+0x5a/0xe0 > [] common_interrupt+0x6f/0x6f > [] ? lock_acquire+0x9e/0x100 > [] ? path_init+0x26d/0x4c0 > [] lg_local_lock+0x34/0x70 > [] ? path_init+0x26d/0x4c0 > [] path_init+0x26d/0x4c0 > [] ? __raw_spin_lock_init+0x38/0x70 > [] path_openat+0x81/0x660 > [] ? handle_mm_fault+0x2d1/0xaf0 > [] ? __do_page_fault+0x148/0x570 > [] do_filp_open+0x43/0xa0 > [] ? _raw_spin_unlock+0x27/0x30 > [] ? __alloc_fd+0xd6/0x130 > [] do_sys_open+0x13c/0x230 > [] SyS_open+0x22/0x30 > [] system_call_fastpath+0x16/0x1b > ---[ end trace bd3f4c22c85fc732 ]--- > > The test itself concludes successfully as written, though it's worth noting > the test does not check the integrity of the data written. > > The same warning can be triggered by the following simple sequence of > commands, extracted from ext4/271: > > mkfs.ext4 /dev/vdc > mount -o dioread_nolock,noload /dev/vdc /vdc > touch /vdc/file > chattr +S /vdc/file > dd if=/dev/zero of=/vdc/file bs=4k count=1 > > (FWIW, if you omit the touch and chattr commands, the warning won't be > triggered unless a second instance of the dd command is issued.) > > The warning bisects cleanly to this patch: > 7b7a8665ed direct-io: Implement generic deferred AIO completions > > Apparently, !io_end->handle is unexpectedly true in this test case. A > WARN_ON for that condition was newly added in the patch. > > It's not yet clear to me how serious this warning is, but the new message is > at least a minor regression. > > Thanks, > Eric > > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Jan Kara SUSE Labs, CR