From: Oliver Neukum <oliver@neukum.org>
To: Alex Riesen <raa.lkml@gmail.com>
Cc: Alan Stern <stern@rowland.harvard.edu>,
Jens Axboe <axboe@kernel.dk>,
linux-usb@vger.kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: USB device cannot be reconnected and khubd "blocked for more than 120 seconds"
Date: Sun, 13 Jan 2013 20:16:11 +0100 [thread overview]
Message-ID: <1406914.PAZOOLqX4X@linux-5eaq.site> (raw)
In-Reply-To: <CALxABCYtKJD4YrPxy6p+Frim8erccp3ine7SVEV9ReoaRh1BWQ@mail.gmail.com>
On Sunday 13 January 2013 18:42:49 Alex Riesen wrote:
> On Sun, Jan 13, 2013 at 5:56 PM, Alan Stern <stern@rowland.harvard.edu> wrote:
> > On Sun, 13 Jan 2013, Alex Riesen wrote:
> >>
> >> Yes, almost. What about khubd hanging when machine is shutdown?
> >
> > What about it? I have trouble understanding all the descriptions you
> > have provided so far, because you talk about several different things
> > and change your mind a lot. Can you provide a single, simple scenario
> > that illustrates this problem?
>
> 1. Compile a kernel with deadline elevator as module
> 2. Boot into it, make sure the elevator is selected
> (I used "elevator=deadline" in the kernel command line)
> 3. Insert a FAT formatted mass storage device in an USB2 port
> Observe "io scheduler deadline registered"
> 4. Pull the stick out, wait a moment, and either shutdown or just
> and press alt-sysrq-W:
That makes it clear. The elevator probably has scheduled work
which cannot finish waiting on a lock and scsi_remove_host()
wants to flush work.
This is not a USB problem. You need to involve the SCSI people.
khubd just stops working because disconnects are processed
in its context and the removal deadlocks.
Regards
Oliver
next prev parent reply other threads:[~2013-01-13 19:16 UTC|newest]
Thread overview: 93+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-11 21:04 USB device cannot be reconnected and khubd "blocked for more than 120 seconds" Alex Riesen
2013-01-12 7:48 ` Alex Riesen
2013-01-12 9:18 ` Lan Tianyu
2013-01-12 17:37 ` Alan Stern
2013-01-12 19:39 ` Alex Riesen
2013-01-12 20:33 ` Alex Riesen
2013-01-12 22:52 ` Alan Stern
2013-01-13 12:09 ` Alex Riesen
2013-01-13 16:56 ` Alan Stern
2013-01-13 17:42 ` Alex Riesen
2013-01-13 19:16 ` Oliver Neukum [this message]
2013-01-14 2:39 ` Alan Stern
2013-01-14 16:43 ` Alex Riesen
2013-01-14 3:47 ` Ming Lei
2013-01-14 7:15 ` Ming Lei
2013-01-14 17:30 ` Linus Torvalds
2013-01-14 18:04 ` Alan Stern
2013-01-14 18:34 ` Linus Torvalds
2013-01-15 1:53 ` Ming Lei
2013-01-15 6:23 ` Ming Lei
2013-01-15 17:36 ` Linus Torvalds
2013-01-15 18:18 ` Linus Torvalds
2013-01-15 23:17 ` Tejun Heo
2013-01-15 18:20 ` Alan Stern
2013-01-15 18:39 ` Tejun Heo
2013-01-15 18:32 ` Tejun Heo
2013-01-15 20:18 ` Linus Torvalds
2013-01-15 23:50 ` Tejun Heo
2013-01-16 0:25 ` Arjan van de Ven
2013-01-16 0:35 ` Tejun Heo
2013-01-16 4:01 ` Alan Stern
2013-01-16 16:12 ` Tejun Heo
2013-01-16 17:01 ` Alan Stern
2013-01-16 17:37 ` Tejun Heo
2013-01-16 17:51 ` Alan Stern
2013-01-16 0:36 ` Linus Torvalds
2013-01-16 0:40 ` Linus Torvalds
2013-01-16 2:52 ` [PATCH] module, async: async_synchronize_full() on module init iff async is used Tejun Heo
2013-01-16 3:00 ` Linus Torvalds
2013-01-16 3:25 ` Tejun Heo
2013-01-16 3:37 ` Linus Torvalds
2013-01-16 16:22 ` Arjan van de Ven
2013-01-16 16:48 ` Tejun Heo
2013-01-16 17:03 ` Arjan van de Ven
2013-01-16 17:06 ` Linus Torvalds
2013-01-16 21:30 ` [PATCH 1/2] init, block: try to load default elevator module early during boot Tejun Heo
2013-01-17 18:05 ` Linus Torvalds
2013-01-17 18:38 ` Tejun Heo
2013-01-17 18:46 ` Linus Torvalds
2013-01-17 18:59 ` Tejun Heo
2013-01-17 19:00 ` Linus Torvalds
2013-01-18 1:24 ` [PATCH 1/3] workqueue: set PF_WQ_WORKER on rescuers Tejun Heo
2013-01-18 1:25 ` [PATCH 2/3] workqueue, async: implement work/async_current_func() Tejun Heo
2013-01-18 2:47 ` Linus Torvalds
2013-01-18 2:59 ` Tejun Heo
2013-01-18 3:04 ` Tejun Heo
2013-01-18 3:18 ` Linus Torvalds
2013-01-18 3:47 ` Tejun Heo
2013-01-18 22:08 ` [PATCH 1/5] workqueue: set PF_WQ_WORKER on rescuers Tejun Heo
2013-01-18 22:10 ` [PATCH 2/5] workqueue: rename kernel/workqueue_sched.h to kernel/workqueue_internal.h Tejun Heo
2013-01-18 22:11 ` [PATCH 3/5] workqueue: move struct worker definition to workqueue_internal.h Tejun Heo
2013-01-18 22:11 ` [PATCH 4/5] workqueue: implement current_is_async() Tejun Heo
2013-01-18 22:12 ` [PATCH 5/5] async, kmod: warn on synchronous request_module() from async workers Tejun Heo
2022-06-23 5:25 ` Saravana Kannan
2013-01-18 1:27 ` [PATCH 3/3] " Tejun Heo
2013-01-23 0:53 ` [PATCH v2 1/2] init, block: try to load default elevator module early during boot Tejun Heo
2013-01-16 21:31 ` [PATCH 2/2] block: don't request module during elevator init Tejun Heo
2013-01-23 0:51 ` [PATCH v2 " Tejun Heo
2013-01-16 3:30 ` [PATCH] module, async: async_synchronize_full() on module init iff async is used Ming Lei
2013-01-16 4:24 ` Rusty Russell
2013-01-16 11:36 ` Alex Riesen
2013-08-12 7:04 ` [3.8-rc3 -> 3.8-rc4 regression] " Jonathan Nieder
2013-08-12 15:09 ` Tejun Heo
2013-11-26 21:29 ` Josh Hunt
2013-11-26 21:53 ` Linus Torvalds
2013-11-26 22:12 ` Josh Hunt
2013-11-26 22:29 ` Tejun Heo
2013-12-03 14:28 ` Josh Hunt
2013-12-03 15:19 ` Tejun Heo
2013-12-04 23:01 ` Josh Hunt
2013-12-04 23:12 ` Tejun Heo
2013-11-26 22:30 ` Linus Torvalds
2013-01-16 0:44 ` USB device cannot be reconnected and khubd "blocked for more than 120 seconds" Tejun Heo
2013-01-16 17:19 ` [PATCH] async: fix __lowest_in_progress() Tejun Heo
2013-01-17 18:16 ` Linus Torvalds
2013-01-17 18:50 ` Tejun Heo
2013-01-23 0:15 ` [PATCH v2] " Tejun Heo
2013-01-23 0:22 ` Linus Torvalds
2013-01-16 3:05 ` USB device cannot be reconnected and khubd "blocked for more than 120 seconds" Ming Lei
2013-01-16 4:14 ` Linus Torvalds
2013-01-14 8:22 ` Oliver Neukum
2013-01-14 8:40 ` Ming Lei
2013-01-12 19:56 ` Alex Riesen
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