From: Linus Torvalds <torvalds@linux-foundation.org>
To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: Jens Axboe <axboe@kernel.dk>, Eric Biggers <ebiggers3@gmail.com>,
Eryu Guan <guaneryu@gmail.com>,
Fengguang Wu <fengguang.wu@intel.com>,
Lukas Czerner <lczerner@redhat.com>, Jan Kara <jack@suse.cz>,
Jeff Moyer <jmoyer@redhat.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
xfs <linux-xfs@vger.kernel.org>
Subject: Re: [btrfs] WARNING: CPU: 0 PID: 6379 at fs/direct-io.c:293 dio_complete+0x1d4/0x220
Date: Mon, 13 Nov 2017 14:01:36 -0800 [thread overview]
Message-ID: <CA+55aFzQM747SW959w3CDD=6UypUa7XTqEyHnPaTcFCX+vDLGA@mail.gmail.com> (raw)
In-Reply-To: <20171113215601.GD6246@magnolia>
On Mon, Nov 13, 2017 at 1:56 PM, Darrick J. Wong
<darrick.wong@oracle.com> wrote:
> Wellll... the WARN_ON in question happens when:
>
> a) two programs race to write to the same part of a file, one via the page
> cache and the other via directio
> b) the dio write completes, tries to invalidate the page cache, and fails
> because the corresponding page cannot be invalidated
>
> At this point, the page cache contents don't reflect what's on disk, so
> I don't think we can quietly ignore the situation.
Direct-IO causing cache coherency issues? Really? I'm shocked and
surptised that that could _possibly_ happen.
But why the hell would you want a back-trace for it?
IOW, if you want to warn about it, use "pr_warn_ratelimited()" or
something. What did the backtrace and "looks like a kernel oops"
really help with?
And in the end, maybe even the warning is pointless. You used
direct-IO and cached IO at the same time, and you got coherency
issues. What did you expect? directio is fundamentally broken.
Linus
next prev parent reply other threads:[~2017-11-13 22:01 UTC|newest]
Thread overview: 101+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-23 11:03 Linux 4.14-rc6 Linus Torvalds
2017-10-29 22:51 ` Fengguang Wu
2017-10-29 23:02 ` [perf_event_ctx_lock_nested] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:97 Fengguang Wu
2017-10-30 8:42 ` Peter Zijlstra
2017-10-30 8:52 ` Fengguang Wu
2017-10-29 23:10 ` [o2nm_depend_item] BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:52 Fengguang Wu
2017-10-29 23:23 ` Fengguang Wu
2017-10-30 1:48 ` Eric Ren
2017-10-30 1:48 ` [Ocfs2-devel] " Eric Ren
2017-10-30 2:04 ` piaojun
2017-10-30 2:04 ` [Ocfs2-devel] " piaojun
2017-10-29 23:18 ` [ghes_copy_tofrom_phys] BUG: sleeping function called from invalid context at mm/page_alloc.c:4150 Fengguang Wu
2017-10-30 11:05 ` Borislav Petkov
2017-10-30 14:01 ` Tyler Baicar
2017-10-30 14:06 ` Borislav Petkov
2017-10-30 14:17 ` Tyler Baicar
2017-10-30 14:56 ` Borislav Petkov
2017-10-30 17:20 ` Linus Torvalds
2017-10-30 17:42 ` Borislav Petkov
2017-10-30 17:46 ` Linus Torvalds
2017-10-30 17:49 ` Will Deacon
2017-10-30 18:00 ` Linus Torvalds
2017-10-30 20:14 ` Tyler Baicar
2017-10-31 10:38 ` Will Deacon
2017-10-31 12:29 ` Mark Rutland
[not found] ` <20171106224635.qopgsszwxzuitkpf@wfg-t540p.sh.intel.com>
2017-11-06 22:57 ` [v4.14-rc8 ghes_copy_tofrom_phys] BUG: sleeping function called from invalid context at lib/ioremap.c:165 Linus Torvalds
2017-11-06 23:20 ` Fengguang Wu
2017-11-06 23:02 ` Borislav Petkov
2017-11-06 23:04 ` Rafael J. Wysocki
2017-11-07 13:39 ` Fengguang Wu
[not found] ` <20171106225354.6ucl4f4ipsjlntzl@wfg-t540p.sh.intel.com>
2017-11-06 23:12 ` [ata_scsi_offline_dev] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:238 Linus Torvalds
2017-11-07 0:12 ` Tejun Heo
2017-11-07 3:34 ` Martin K. Petersen
2017-11-07 6:55 ` Hannes Reinecke
2017-10-29 23:37 ` [pgtable_trans_huge_withdraw] BUG: unable to handle kernel NULL pointer dereference at 0000000000000020 Fengguang Wu
2017-10-30 9:19 ` Kirill A. Shutemov
2017-10-30 9:19 ` Kirill A. Shutemov
2017-10-30 9:28 ` Fengguang Wu
2017-10-30 9:28 ` Fengguang Wu
2017-10-30 11:27 ` Kirill A. Shutemov
2017-10-30 11:27 ` Kirill A. Shutemov
2017-10-30 11:58 ` Kirill A. Shutemov
2017-10-30 11:58 ` Kirill A. Shutemov
2017-10-30 12:40 ` Zi Yan
2017-10-30 13:24 ` Kirill A. Shutemov
2017-10-30 13:24 ` Kirill A. Shutemov
2017-10-29 23:48 ` [run_timer_softirq] BUG: unable to handle kernel paging request at 0000000000010007 Fengguang Wu
2017-10-30 19:29 ` Linus Torvalds
2017-10-30 20:37 ` Fengguang Wu
2017-11-09 5:19 ` Fengguang Wu
2017-11-10 20:08 ` Linus Torvalds
2017-11-10 21:29 ` Thomas Gleixner
2017-11-11 15:35 ` Fengguang Wu
2017-10-30 6:27 ` Linux 4.14-rc6: WARNING: CPU: 9 PID: 5377 at arch/x86/events/intel/core.c:2228 intel_pmu_handle_irq+0x4a8/0x4c0 Fengguang Wu
2017-10-30 10:02 ` Peter Zijlstra
2017-10-30 22:49 ` Fengguang Wu
2017-10-31 14:57 ` Peter Zijlstra
2017-10-30 6:44 ` [migration_cpu_stop] WARNING: CPU: 0 PID: 11 at arch/x86/kernel/smp.c:128 native_smp_send_reschedule+0x69/0x9e Fengguang Wu
2017-10-30 7:00 ` [haswell_crtc_enable] WARNING: CPU: 3 PID: 109 at drivers/gpu/drm/drm_vblank.c:1066 drm_wait_one_vblank+0x18f/0x1a0 [drm] Fengguang Wu
2017-10-30 7:00 ` Fengguang Wu
2017-10-30 19:10 ` Linus Torvalds
2017-10-30 19:10 ` Linus Torvalds
2017-10-30 20:03 ` [Intel-gfx] " Rodrigo Vivi
2017-10-30 23:17 ` Fengguang Wu
2017-10-30 23:17 ` Fengguang Wu
2017-10-30 20:18 ` Fengguang Wu
2017-10-30 20:18 ` Fengguang Wu
2017-10-30 7:20 ` [btrfs] WARNING: CPU: 0 PID: 6379 at fs/direct-io.c:293 dio_complete+0x1d4/0x220 Fengguang Wu
2017-10-30 7:44 ` Eryu Guan
2017-10-31 0:10 ` Fengguang Wu
2017-10-31 6:54 ` Eryu Guan
2017-10-31 7:10 ` Fengguang Wu
2017-11-06 1:13 ` Eric Biggers
2017-11-13 19:13 ` Eric Biggers
2017-11-13 19:16 ` Jens Axboe
2017-11-13 19:21 ` Linus Torvalds
2017-11-13 21:56 ` Darrick J. Wong
2017-11-13 22:01 ` Linus Torvalds [this message]
2017-11-14 17:17 ` Theodore Ts'o
2017-10-31 15:13 ` Filipe Manana
2017-10-30 7:35 ` [locking/paravirt] static_key_disable_cpuslocked(): static key 'virt_spin_lock_key+0x0/0x20' used before call to jump_label_init() Fengguang Wu
2017-10-30 7:35 ` Fengguang Wu
2017-10-30 7:35 ` Fengguang Wu
2017-10-30 7:47 ` Juergen Gross
2017-10-30 7:47 ` Juergen Gross
2017-10-30 8:38 ` Fengguang Wu
2017-10-30 8:38 ` Fengguang Wu
2017-10-30 8:38 ` Fengguang Wu
2017-10-30 9:56 ` Fengguang Wu
2017-10-30 9:56 ` Fengguang Wu
2017-10-30 9:56 ` Fengguang Wu
2017-10-30 7:47 ` Juergen Gross
2017-10-30 8:43 ` Dou Liyang
2017-10-30 8:43 ` Dou Liyang
2017-10-30 8:43 ` Dou Liyang
2017-10-30 7:40 ` [pmem_attach_disk] WARNING: CPU: 46 PID: 518 at kernel/memremap.c:363 devm_memremap_pages+0x350/0x4b0 Fengguang Wu
2017-10-30 15:59 ` Dan Williams
2017-10-31 0:00 ` Fengguang Wu
2017-10-31 0:24 ` Dan Williams
2017-10-31 7:08 ` Fengguang Wu
2017-11-12 0:15 ` Theodore Ts'o
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