From: navin patidar <navinp@cdac.in>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: gregkh@linuxfoundation.org, mfm@muteddisk.com,
devel@driverdev.osuosl.org, linux-usb@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] staging: usbip: stub_dev: Fixed oops during removal of usbip_host
Date: Tue, 18 Sep 2012 17:14:41 +0530 [thread overview]
Message-ID: <CAPV97yfRd_1Ak+DniNyg+vhg1bkOPqzGwRu-LSKXkpW2=_xw+Q@mail.gmail.com> (raw)
In-Reply-To: <20120918093619.GO13767@mwanda>
for usbip_host event_handler() handles following events. defined
in "usbip_common.h"
1. SDEV_EVENT_REMOVED (USBIP_EH_SHUTDOWN | USBIP_EH_RESET | USBIP_EH_BYE)
2. SDEV_EVENT_DOWN (USBIP_EH_SHUTDOWN | USBIP_EH_RESET)
3. SDEV_EVENT_ERROR_TCP (USBIP_EH_SHUTDOWN | USBIP_EH_RESET)
4. SDEV_EVENT_ERROR_SUBMIT (USBIP_EH_SHUTDOWN | USBIP_EH_RESET)
5. VDEV_EVENT_ERROR_MALLOC (USBIP_EH_SHUTDOWN | USBIP_EH_UNUSABLE)
In case of events(1,2,3,4), stub_shoutdown_connection() gets executed
first and than stub_device_reset() .
In case of event 5, stub_shoutdown_connection() kills kernel threads
and stub_device_unusable() changes devices status to
"SDEV_ST_ERROR"(fatal error).
thus stub_device_reset() can't be called without
stub_shutdown_connection(), so there is no problem of resource leak .
you are also right, i could have set pointers to NULL in
stub_shutdown_connection() but i used stub_device_reset() which is
intended to reset usbip_device stuct member variables.
i'll resend patches, if maintainer ask for that.
thanks
--navin-patidar
On Tue, Sep 18, 2012 at 3:06 PM, Dan Carpenter <dan.carpenter@oracle.com> wrote:
> On Tue, Sep 18, 2012 at 03:02:15PM +0530, navin patidar wrote:
>> On Tue, Sep 18, 2012 at 1:10 PM, Dan Carpenter <dan.carpenter@oracle.com> wrote:
>> > On Tue, Sep 18, 2012 at 09:30:06AM +0530, navin patidar wrote:
>> >> stub_device_reset should set kernel thread pointers to NULL.
>> >> so that at the time of usbip_host removal stub_shoutdown_connection
>> >> doesn't try to kill kernel threads which are already killed.
>> >>
>> >
>> > If you have the Oops output, that's always nice to put in the commit
>> > message.
>>
>> i'll surely keep this in mind before submitting further patches.
>>
>> > Why don't you set the pointers to NULL in stub_shutdown_connection()
>> > since that's where you actually kill the threads. Setting them to
>> > NULL in stub_device_reset() will (sometimes) solve the problem but
>> > it gives you a new problem of a resource leak.
>>
>> stub_device_reset() always gets executed after
>> stub_shutdown_connection() , never before.
>>
>
> No it isn't. Read event_handler() more carefully. They can be
> executed independently.
>
> In other words, stub_shutdown_connection() can be called without
> calling stub_device_reset() and stub_device_reset() can be called
> without stub_shutdown_connection(). If either of those happen then
> it causes a problem with the patch you have just sent.
>
> regards,
> dan carpenter
>
next prev parent reply other threads:[~2012-09-18 11:44 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-18 4:00 [PATCH] staging: usbip: stub_dev: Fixed oops during removal of usbip_host navin patidar
2012-09-18 7:40 ` Dan Carpenter
2012-09-18 9:32 ` navin patidar
2012-09-18 9:36 ` Dan Carpenter
2012-09-18 11:44 ` navin patidar [this message]
2012-09-18 13:15 ` Dan Carpenter
-- strict thread matches above, loose matches on Subject: below --
2012-09-14 13:21 navin patidar
2012-09-14 14:16 ` Dan Carpenter
2012-09-14 14:28 ` Sebastian Andrzej Siewior
2012-09-14 14:41 ` Dan Carpenter
2012-09-14 9:53 navin patidar
2012-09-14 11:42 ` Sergei Shtylyov
2012-09-14 12:04 ` Sebastian Andrzej Siewior
2012-09-14 14:29 ` navin patidar
[not found] ` <CAPV97yfV27x8hB2WUCVmGWEU7i21Y5K5trig2fzQBx+VB_Yk2g@mail.gmail.com>
2012-09-14 14:16 ` Sergei Shtylyov
2012-09-17 12:19 ` Greg KH
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