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From: Sergei Shtylyov <>
To: "" <>
Cc: "" <>,
Subject: Re: [PATCH v2] ravb: Fixed the problem that rmmod can not be done
Date: Fri, 31 Jul 2020 19:28:38 +0300
Message-ID: <> (raw)
In-Reply-To: <>


On 7/31/20 1:18 PM, wrote:

> I understand that the commit log needs to be corrected.

   The subject also could be more concise...

> (Shimoda-san's point is also correct)
> If there is anything else that needs to be corrected, please point it out.

   OK, I'll try to post a proper patch review...

>>    That seems a common pattern, inlluding the Renesas sh_eth
>> driver...
> Yes.

    Not at all so common as I thought! Only 4 drivers use mdio-bitbang, 2 of them are
for the Renesas SoCs...

> If I can get an R-Car Gen2 board, I will also fix sh_eth driver.

    Do yuo have R-Car V3H at hand, by chance? It does have a GEther controler used for
booting up... 

>>    No, the driver's remove() method calls ravb_mdio_release() and
>> that one calls
>> free_mdio_bitbang() that calls module_put(); the actual reason lies
>> somewehre deeper than this...
> No.
> Running rmmod calls delete_module() in kernel/module.c before ravb_mdio_release() is called.
> delete_module()
>    -> try_stop_module()
>      -> try_release_module_ref()
> In try_release_module_ref(), check refcnt and if it is counted up, ravb_mdio_release() is not
> called and rmmod is terminated.

   Yes, after some rummaging in the module support code, I have to agree here. I was
just surprised with you finding such a critical bug so late in the drivers' life cycle.
Well, due to usually using NFS the EtherAVB (and Ether too) driver is probably alwaysbuilt in-kernel...

> Thanks & Best Regards,
> Yuusuke Ashizuka <>

   Trim your messages after your goodbye. That original message stuff typically isn't
tolerated in the Linux mailing lists, nearly the same as top-posting...


MBR, Sergei

  reply index

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-30  3:56 [PATCH] " Yuusuke Ashizuka
2020-07-30  7:55 ` kernel test robot
2020-07-30 10:01 ` [PATCH v2] " Yuusuke Ashizuka
2020-07-30 11:37   ` Yoshihiro Shimoda
2020-07-30 16:24     ` Sergei Shtylyov
2020-07-31  6:43       ` Yoshihiro Shimoda
2020-07-31 17:45         ` Sergei Shtylyov
2020-07-30 16:04   ` Sergei Shtylyov
2020-07-31 10:18     ` ashiduka
2020-07-31 16:28       ` Sergei Shtylyov [this message]
2020-08-06  2:26         ` ashiduka
2020-07-31 18:32   ` Sergei Shtylyov
2020-08-06  2:28     ` ashiduka

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