LKML Archive on
help / color / mirror / Atom feed
From: Gen Zhang <>
To: Kalle Valo <>
Subject: Re: [PATCH] wlcore: spi: Fix a memory leaking bug in wl1271_probe()
Date: Tue, 28 May 2019 20:14:52 +0800	[thread overview]
Message-ID: <20190528121452.GA23464@zhanggen-UX430UQ> (raw)
In-Reply-To: <>

On Tue, May 28, 2019 at 11:39:22AM +0000, Kalle Valo wrote:
> Gen Zhang <> wrote:
> > In wl1271_probe(), 'glue->core' is allocated by platform_device_alloc(),
> > when this allocation fails, ENOMEM is returned. However, 'pdev_data'
> > and 'glue' are allocated by devm_kzalloc() before 'glue->core'. When
> > platform_device_alloc() returns NULL, we should also free 'pdev_data'
> > and 'glue' before wl1271_probe() ends to prevent leaking memory.
> > 
> > Similarly, we shoulf free 'pdev_data' when 'glue' is NULL. And we should
> > free 'pdev_data' and 'glue' when 'glue->reg' is error and when 'ret' is
> > error.
> > 
> > Further, we should free 'glue->core', 'pdev_data' and 'glue' when this 
> > function normally ends to prevent leaking memory.
> > 
> > Signed-off-by: Gen Zhang <>
> Same questions as with similar SDIO patch:
> Patch set to Changes Requested.
> -- 
Thanks for your reply, Kalle. I had debate with Jon about this patch. 
You could kindly refer to lkml: 
And I don't think a practical conclusion is made there.

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 
> ( 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?


  parent reply	other threads:[~2019-05-28 12:15 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-24  3:02 Gen Zhang
2019-05-28 11:39 ` Kalle Valo
     [not found] ` <>
2019-05-28 12:14   ` Gen Zhang [this message]
2019-05-28 12:33     ` Kalle Valo
2019-05-28 12:38       ` Gen Zhang

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190528121452.GA23464@zhanggen-UX430UQ \ \ \ \ \ \ \
    --subject='Re: [PATCH] wlcore: spi: Fix a memory leaking bug in wl1271_probe()' \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).