Re: [PATCHES] Networking fixes for -stable.

Re: [PATCHES] Networking fixes for -stable.

[Ben Hutchings]

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On Mon, 2012-11-12 at 00:25 -0500, David Miller wrote:
> Please queue up the following networking bug fixes for
> 3.0.x, 3.2.x, 3.4.x, and 3.6.x, respectively.
[...]
> From 2204849a85383fbde75680aa199142abe504adbb Mon Sep 17 00:00:00 2001
> From: Peter Senna Tschudin <peter.senna@gmail.com>
> Date: Sun, 28 Oct 2012 06:12:01 +0000
> Subject: [PATCH 7/9] drivers/net/phy/mdio-bitbang.c: Call mdiobus_unregister
>  before mdiobus_free
> 
> [ Upstream commit aa731872f7d33dcb8b54dad0cfb82d4e4d195d7e ]
> 
> Based on commit b27393aecf66199f5ddad37c302d3e0cfadbe6c0
> 
> Calling mdiobus_free without calling mdiobus_unregister causes
> BUG_ON(). This patch fixes the issue.
[...]

This introduces a regresssion, as mdiobus_unregister() is not safe to
call if the bus isn't registered.  Registration is controlled by the
drivers that use mdio-bitbang, and they should take care of
unregistration too - and most of them do.

This should be reverted in mainline and not applied to any stable
series.

Ben.

-- 
Ben Hutchings
For every complex problem
there is a solution that is simple, neat, and wrong.

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Re: [PATCHES] Networking fixes for -stable.

[Peter Senna Tschudin]

Hi Ben,

On Tue, Nov 13, 2012 at 8:51 PM, Ben Hutchings <ben@decadent.org.uk> wrote:
> On Mon, 2012-11-12 at 00:25 -0500, David Miller wrote:
>> Please queue up the following networking bug fixes for
>> 3.0.x, 3.2.x, 3.4.x, and 3.6.x, respectively.
> [...]
>> From 2204849a85383fbde75680aa199142abe504adbb Mon Sep 17 00:00:00 2001
>> From: Peter Senna Tschudin <peter.senna@gmail.com>
>> Date: Sun, 28 Oct 2012 06:12:01 +0000
>> Subject: [PATCH 7/9] drivers/net/phy/mdio-bitbang.c: Call mdiobus_unregister
>>  before mdiobus_free
>>
>> [ Upstream commit aa731872f7d33dcb8b54dad0cfb82d4e4d195d7e ]
>>
>> Based on commit b27393aecf66199f5ddad37c302d3e0cfadbe6c0
>>
>> Calling mdiobus_free without calling mdiobus_unregister causes
>> BUG_ON(). This patch fixes the issue.
> [...]
>
> This introduces a regresssion, as mdiobus_unregister() is not safe to
> call if the bus isn't registered.  Registration is controlled by the
> drivers that use mdio-bitbang, and they should take care of
> unregistration too - and most of them do.

Is mdiobus_free() safe to call if the bus isn't registered?

I found calls to free_mdio_bitbang() after call to
mdiobus_unregister() that may be the worst cases for my patch. But I
also found places that call free_mdio_bitbang() without first calling
mdiobus_unregister(). See:

linux-next/arch/powerpc/platforms/82xx/ep8248e.c:152
linux-next/drivers/net/ethernet/8390/ax88796.c:647
linux-next/drivers/net/ethernet/freescale/fs_enet/mii-bitbang.c:197
linux-next/drivers/net/phy/mdio-gpio.c:157
linux-next/drivers/net/phy/mdio-gpio.c:172

Are those calls to free_mdio_bitbang() wrong by not calling
mdiobus_unregister() before?

>
> This should be reverted in mainline and not applied to any stable
> series.
>
> Ben.
>
> --
> Ben Hutchings
> For every complex problem
> there is a solution that is simple, neat, and wrong.

Thank you for reviewing,

Peter

--
Peter

Re: [PATCHES] Networking fixes for -stable.

[Ben Hutchings]

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On Wed, 2012-11-14 at 15:02 +0100, Peter Senna Tschudin wrote:
> Hi Ben,
> 
> On Tue, Nov 13, 2012 at 8:51 PM, Ben Hutchings <ben@decadent.org.uk> wrote:
> > On Mon, 2012-11-12 at 00:25 -0500, David Miller wrote:
> >> Please queue up the following networking bug fixes for
> >> 3.0.x, 3.2.x, 3.4.x, and 3.6.x, respectively.
> > [...]
> >> From 2204849a85383fbde75680aa199142abe504adbb Mon Sep 17 00:00:00 2001
> >> From: Peter Senna Tschudin <peter.senna@gmail.com>
> >> Date: Sun, 28 Oct 2012 06:12:01 +0000
> >> Subject: [PATCH 7/9] drivers/net/phy/mdio-bitbang.c: Call mdiobus_unregister
> >>  before mdiobus_free
> >>
> >> [ Upstream commit aa731872f7d33dcb8b54dad0cfb82d4e4d195d7e ]
> >>
> >> Based on commit b27393aecf66199f5ddad37c302d3e0cfadbe6c0
> >>
> >> Calling mdiobus_free without calling mdiobus_unregister causes
> >> BUG_ON(). This patch fixes the issue.
> > [...]
> >
> > This introduces a regresssion, as mdiobus_unregister() is not safe to
> > call if the bus isn't registered.  Registration is controlled by the
> > drivers that use mdio-bitbang, and they should take care of
> > unregistration too - and most of them do.
> 
> Is mdiobus_free() safe to call if the bus isn't registered?
[...]

It must be, otherwise what do you do if mdiobus_register() fails?

Ben.

-- 
Ben Hutchings
friends: People who know you well, but like you anyway.

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Re: [PATCHES] Networking fixes for -stable.

[David Miller]

From: Ben Hutchings <ben@decadent.org.uk>
Date: Tue, 13 Nov 2012 19:51:26 +0000

> On Mon, 2012-11-12 at 00:25 -0500, David Miller wrote:
>> Please queue up the following networking bug fixes for
>> 3.0.x, 3.2.x, 3.4.x, and 3.6.x, respectively.
> [...]
>> From 2204849a85383fbde75680aa199142abe504adbb Mon Sep 17 00:00:00 2001
>> From: Peter Senna Tschudin <peter.senna@gmail.com>
>> Date: Sun, 28 Oct 2012 06:12:01 +0000
>> Subject: [PATCH 7/9] drivers/net/phy/mdio-bitbang.c: Call mdiobus_unregister
>>  before mdiobus_free
>> 
>> [ Upstream commit aa731872f7d33dcb8b54dad0cfb82d4e4d195d7e ]
>> 
>> Based on commit b27393aecf66199f5ddad37c302d3e0cfadbe6c0
>> 
>> Calling mdiobus_free without calling mdiobus_unregister causes
>> BUG_ON(). This patch fixes the issue.
> [...]
> 
> This introduces a regresssion, as mdiobus_unregister() is not safe to
> call if the bus isn't registered.  Registration is controlled by the
> drivers that use mdio-bitbang, and they should take care of
> unregistration too - and most of them do.
> 
> This should be reverted in mainline and not applied to any stable
> series.

Ok, I'll revert.

Greg, please toss it from your -stable queue as well.

Thanks!

Re: [PATCHES] Networking fixes for -stable.

[Greg KH]

On Wed, Nov 14, 2012 at 10:31:45PM -0500, David Miller wrote:
> From: Ben Hutchings <ben@decadent.org.uk>
> Date: Tue, 13 Nov 2012 19:51:26 +0000
> 
> > On Mon, 2012-11-12 at 00:25 -0500, David Miller wrote:
> >> Please queue up the following networking bug fixes for
> >> 3.0.x, 3.2.x, 3.4.x, and 3.6.x, respectively.
> > [...]
> >> From 2204849a85383fbde75680aa199142abe504adbb Mon Sep 17 00:00:00 2001
> >> From: Peter Senna Tschudin <peter.senna@gmail.com>
> >> Date: Sun, 28 Oct 2012 06:12:01 +0000
> >> Subject: [PATCH 7/9] drivers/net/phy/mdio-bitbang.c: Call mdiobus_unregister
> >>  before mdiobus_free
> >> 
> >> [ Upstream commit aa731872f7d33dcb8b54dad0cfb82d4e4d195d7e ]
> >> 
> >> Based on commit b27393aecf66199f5ddad37c302d3e0cfadbe6c0
> >> 
> >> Calling mdiobus_free without calling mdiobus_unregister causes
> >> BUG_ON(). This patch fixes the issue.
> > [...]
> > 
> > This introduces a regresssion, as mdiobus_unregister() is not safe to
> > call if the bus isn't registered.  Registration is controlled by the
> > drivers that use mdio-bitbang, and they should take care of
> > unregistration too - and most of them do.
> > 
> > This should be reverted in mainline and not applied to any stable
> > series.
> 
> Ok, I'll revert.
> 
> Greg, please toss it from your -stable queue as well.

Now tossed, thanks.

greg k-h