From: Mauro Carvalho Chehab <mchehab@redhat.com>
To: Chris Rankin <rankincj@yahoo.com>
Cc: linux-media@vger.kernel.org
Subject: Re: [PATCH v3] EM28xx - fix deadlock when unplugging and replugging a DVB adapter
Date: Sun, 25 Sep 2011 16:45:12 -0300 [thread overview]
Message-ID: <4E7F84C8.6010505@redhat.com> (raw)
In-Reply-To: <1316978885.75743.YahooMailClassic@web121708.mail.ne1.yahoo.com>
Em 25-09-2011 16:28, Chris Rankin escreveu:
> --- On Sun, 25/9/11, Mauro Carvalho Chehab <mchehab@redhat.com> wrote:
>> Ok, I've applied it, but it doesn't sound a good idea to me
>> to do:
>>
>> + mutex_unlock(&dev->lock);
>> em28xx_init_extension(dev);
>> + mutex_lock(&dev->lock);
>>
>
> Yes, I suppose it's the logical equivalent of moving the em28xx_init_extension(dev) call from em28xx_init_dev(), and placing it immediately after the final mutex_unlock(&dev->lock) call in em28xx_usb_probe() instead. Which would be cleaner, quite frankly.
>
> Which stage of the v4l2 initialisation triggers the race with udev? v4l2_device_register()?
Yes. Just after creating a device, udev tries to access it. This bug is more sensitive on
multi-CPU machines, as udev may run on another CPU.
>
> Cheers,
> Chris
>
next prev parent reply other threads:[~2011-09-25 19:45 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-24 20:54 [PATCH v3] EM28xx - fix deadlock when unplugging and replugging a DVB adapter Chris Rankin
2011-09-25 12:49 ` Mauro Carvalho Chehab
2011-09-25 13:20 ` Chris Rankin
2011-09-25 19:28 ` Chris Rankin
2011-09-25 19:45 ` Mauro Carvalho Chehab [this message]
2011-09-25 21:36 ` Chris Rankin
2011-09-25 13:00 ` Mauro Carvalho Chehab
2011-09-25 13:32 ` Chris Rankin
2011-09-25 19:43 ` Mauro Carvalho Chehab
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