linux-kernel - Re: mwifiex: don't do unbalanced free()'ing in cleanup

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Date:   Fri, 18 Nov 2016 11:25:21 +0000 (UTC)
From:   Kalle Valo <kvalo@...eaurora.org>
To:     Brian Norris <briannorris@...omium.org>
Cc:     Amitkumar Karwar <akarwar@...vell.com>,
        Nishant Sarmukadam <nishants@...vell.com>,
        <linux-kernel@...r.kernel.org>, linux-wireless@...r.kernel.org,
        Cathy Luo <cluo@...vell.com>, Rajat Jain <rajatja@...gle.com>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Brian Norris <briannorris@...omium.org>
Subject: Re: mwifiex: don't do unbalanced free()'ing in cleanup_if()

Brian Norris <briannorris@...omium.org> wrote:
> The cleanup_if() callback is the inverse of init_if(). We allocate our
> 'card' interface structure in the probe() function, but we free it in
> cleanup_if(). That gives a few problems:
> (a) we leak this memory if probe() fails before we reach init_if()
> (b) we can't safely utilize 'card' after cleanup_if() -- namely, in
>     remove() or suspend(), both of which might race with the cleanup
>     paths in our asynchronous FW initialization path
> 
> Solution: just use devm_kzalloc(), which will free this structure
> properly when the device is removed -- and drop the set_drvdata(...,
> NULL), since the driver core does this for us. This also removes the
> temptation to use drvdata == NULL as a hack for checking if the device
> has been "cleaned up."
> 
> I *do* leave the set_drvdata(..., NULL) for the hacky SDIO
> mwifiex_recreate_adapter(), since the device core won't be able to clear
> that one for us.
> 
> Signed-off-by: Brian Norris <briannorris@...omium.org>

Patch applied to wireless-drivers-next.git, thanks.

66b9c182538e mwifiex: don't do unbalanced free()'ing in cleanup_if()

-- 
https://patchwork.kernel.org/patch/9398689/

Documentation about submitting wireless patches and checking status
from patchwork:

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches