From: Greg KH <gregkh@linuxfoundation.org>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: Michael Welling <mwelling@ieee.org>,
Roland Dreier <rolandd@cisco.com>,
kernel test robot <ying.huang@linux.intel.com>,
lkp@01.org, LKML <linux-kernel@vger.kernel.org>,
Arnd Bergmann <arnd@arndb.de>,
Markus Pargmann <mpa@pengutronix.de>,
Johan Hovold <johan@kernel.org>
Subject: Re: [lkp] [gpio] 3c702e9987: kmsg.user_verbs:couldn't_register_device_number
Date: Sun, 14 Feb 2016 11:05:15 -0800 [thread overview]
Message-ID: <20160214190515.GA23912@kroah.com> (raw)
In-Reply-To: <CACRpkda-8iz4XavJLYpDQEAmoL19dPNGqR2YK6eNOLBdqQz2nQ@mail.gmail.com>
On Sun, Feb 14, 2016 at 06:56:20PM +0100, Linus Walleij wrote:
> On Sun, Feb 14, 2016 at 6:49 PM, Greg KH <gregkh@linuxfoundation.org> wrote:
> > On Sun, Feb 14, 2016 at 06:42:11PM +0100, Linus Walleij wrote:
> >> Greg, heads-up on this... you'd know if this happened
> >> before.
> >>
> >> On Sun, Feb 14, 2016 at 9:06 AM, Michael Welling <mwelling@ieee.org> wrote:
> >> > On Sun, Feb 14, 2016 at 02:59:06PM +0800, kernel test robot wrote:
> >> >> FYI, we noticed the below changes on
> >> >>
> >> >> https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio.git chardev
> >> >> commit 3c702e9987e261042a07e43460a8148be254412e ("gpio: add a userspace chardev ABI for GPIOs")
> >> >>
> >> >>
> >> >> [ 1.951191] user_verbs: couldn't register device number
> >> >
> >> > Looks like user_verbs is using a static device node setup.
> >> >
> >> > enum {
> >> > IB_UVERBS_MAJOR = 231,
> >> > IB_UVERBS_BASE_MINOR = 192,
> >> > IB_UVERBS_MAX_DEVICES = 32
> >> > };
> >> >
> >> > #define IB_UVERBS_BASE_DEV MKDEV(IB_UVERBS_MAJOR, IB_UVERBS_BASE_MINOR)
> >>
> >> That's annoying...
> >> I notice that infiniband is using register_chrdev_region() at
> >> module_init() time, counting on device major 231 to be free.
> >
> > That device major is assigned to Infiniband, why shouldn't it be doing
> > this?
>
> I mean it's annoying that they collide. (Because of the details I
> write below, it's fine it's using the assigned number.
>
> > Why not just ask for a new reserved one? We could give you 261 and
> > everything should be fine, right?
>
> Sure I can post a patch for that, but it just mitigates the problem.
>
> The report point to the serious problem that on this system
> some dynamic allocations have already stolen major device
> numbers 232 thru 255, and 232 and 233 are also assigned.
>
> What do you think about a patch that makes fs/char_dev.c
> emit a warning when it starts assigning dynamic numbers
> 233 and below?
That's fine with me. I also think maybe we should look into just
switching all char major/minor allocation to be dynamic, starting at the
bottom and moving up. I think the only tools that might have an issue
with that is the raw device controller, but maybe that has been fixed up
in userspace, I haven't looked at that in many years.
I thought I had an old patch around somewhere that did that, will go
look for it this week and see what breaks with it enabled...
thanks,
greg k-h
next prev parent reply other threads:[~2016-02-14 19:05 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-14 6:59 [lkp] [gpio] 3c702e9987: kmsg.user_verbs:couldn't_register_device_number kernel test robot
2016-02-14 8:06 ` Michael Welling
2016-02-14 17:42 ` Linus Walleij
2016-02-14 17:49 ` Greg KH
2016-02-14 17:56 ` Linus Walleij
2016-02-14 19:05 ` Greg KH [this message]
2016-02-14 19:51 ` Michael Welling
2016-02-14 23:49 ` Greg KH
2016-02-15 4:21 ` Michael Welling
2016-02-14 17:48 ` Linus Walleij
2016-02-15 2:39 ` [LKP] " Huang, Ying
2016-02-15 9:36 ` Linus Walleij
2016-02-23 6:35 ` Huang, Ying
2016-02-23 21:50 ` Michael Welling
2016-02-24 16:01 ` Linus Walleij
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