From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: Aaro Koskinen <aaro.koskinen@nsn.com>,
"Hans J. Koch" <hjk@hansjkoch.de>,
linux-kernel@vger.kernel.org,
Michal Simek <michal.simek@xilinx.com>
Subject: Re: [PATCH] uio: fix devm_request_irq usage
Date: Fri, 20 Dec 2013 10:56:50 -0800 [thread overview]
Message-ID: <20131220185650.GA26584@kroah.com> (raw)
In-Reply-To: <20131220180113.GF2881@blackmetal.musicnaut.iki.fi>
On Fri, Dec 20, 2013 at 08:01:13PM +0200, Aaro Koskinen wrote:
> Hi,
>
> On Fri, Dec 20, 2013 at 08:49:13AM -0800, Greg Kroah-Hartman wrote:
> > On Fri, Dec 20, 2013 at 04:19:47PM +0200, Aaro Koskinen wrote:
> > > Commit e6789cd3dfb553077606ccafeb05e0043f072481 (uio: Simplify uio error
> > > path by using devres functions) converted uio to use devm_request_irq().
> > > This introduced a change in behaviour since the IRQ is associated with
> > > the parent device instead of the created UIO device. The IRQ will remain
> > > active after uio_unregister_device() is called, and some drivers will
> > > crash because of this. The patch fixes this.
> >
> > What drivers crash because of this? Any in-kernel drivers?
>
> I saw a crash with Intel DPDK (http://www.dpdk.org/) igb_uio
> driver. Basically, they do:
>
> uio_unregister_device
> pci_disable_msix <-- this will BUG() if there is an active IRQ
>
> I cannot test any of the in-tree UIO drivers, but at least some
> of them seem to release resources the IRQ handler might use after
> uio_unregister_device(). So if the IRQ fires results would not probably
> be very good.
Ok, thanks, I'll queue this up for 3.14-rc1 and tag it for 3.13-stable
so that people who have external modules can get the fix then.
greg k-h
prev parent reply other threads:[~2013-12-20 18:56 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-20 14:19 [PATCH] uio: fix devm_request_irq usage Aaro Koskinen
2013-12-20 16:49 ` Greg Kroah-Hartman
2013-12-20 18:01 ` Aaro Koskinen
2013-12-20 18:56 ` Greg Kroah-Hartman [this message]
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