netdev - Re: [PATCH] wlcore: spi: Fix a memory leaking bug in wl1271

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Date:   Tue, 28 May 2019 20:38:58 +0800
From:   Gen Zhang <blackgod016574@...il.com>
To:     Kalle Valo <kvalo@...eaurora.org>
Cc:     davem@...emloft.net, linux-wireless@...r.kernel.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] wlcore: spi: Fix a memory leaking bug in wl1271_probe()

On Tue, May 28, 2019 at 03:33:09PM +0300, Kalle Valo wrote:
> Yeah, I don't see how that thread proves that these patches are correct.
> 
Sure, I didn't mean that we came to an agreement that these patches are
correct.
> > Further, I e-mailed Greg K-H about when should we use devm_kmalloc().
> >
> > On Tue, May 28, 2019 at 08:32:57AM +0800, Gen Zhang wrote:
> >> devm_kmalloc() is used to allocate memory for a driver dev. Comments
> >> above the definition and doc 
> >> (https://www.kernel.org/doc/Documentation/driver-model/devres.txt) all
> >> imply that allocated the memory is automatically freed on driver attach,
> >> no matter allocation fail or not. However, I examined the code, and
> >> there are many sites that devm_kfree() is used to free devm_kmalloc().
> >> e.g. hisi_sas_debugfs_init() in drivers/scsi/hisi_sas/hisi_sas_main.c.
> >> So I am totally confused about this issue. Can anybody give me some
> >> guidance? When should we use devm_kfree()?
> > He replied: If you "know" you need to free the memory now, 
> > call devm_kfree(). If you want to wait for it to be cleaned up latter, 
> > like normal, then do not call it.
> >
> > So could please look in to this issue?
> 
> Sorry, no time to investigate this in detail. If you think the patches
> are correct you can resend them and get someone familiar with the driver
> to provide Reviewed-by, then I will apply them.
> 
> -- 
> Kalle Valo
Ok, thanks for your time. I will follow your suggestions.

Thanks
Gen