linux-kernel - Re: Possible memory leak in request

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Date:	Tue, 07 Jul 2009 22:50:45 +0100
From:	Catalin Marinas <catalin.marinas@....com>
To:	Cornelia Huck <cornelia.huck@...ibm.com>
Cc:	Greg Kroah-Hartman <gregkh@...e.de>,
	Ming Lei <tom.leiming@...il.com>,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: Possible memory leak in request_firmware()

On Tue, 2009-07-07 at 19:01 +0200, Cornelia Huck wrote:
> On Tue, 07 Jul 2009 16:17:00 +0100,
> Catalin Marinas <catalin.marinas@....com> wrote:
> 
> > The patch below may fix the problem but it's only later tonight that I
> > can test it and confirm:
> 
> Your patch looks fine to me (didn't test it either), just one minor nit:

I tested it and it solves this leak.

> > @@ -407,14 +407,13 @@ static int fw_register_device(struct device **dev_p, const char *fw_name,
> >  	retval = device_register(f_dev);
> >  	if (retval) {
> >  		dev_err(device, "%s: device_register failed\n", __func__);
> > +		kfree(fw_priv->fw_id);
> 
> fw_priv->fw_id will be freed in the release function, so you don't need
> to free it here.

OK, thanks.

There is one more leak in this area which I couldn't figure out where it
should be freed:

unreferenced object 0xc353e530 (size 512):
  comm "cat", pid 3130, jiffies 4294903232
  backtrace:
    [<c01e6f6a>] create_object+0xfa/0x250
    [<c01e753d>] kmemleak_alloc+0x5d/0x70
    [<c01e223d>] __kmalloc+0x10d/0x210
    [<c03b2d2f>] firmware_data_write+0x1df/0x270
    [<c024163a>] write+0x13a/0x1b0
    [<c01eae1c>] vfs_write+0x9c/0x190
    [<c01eafcd>] sys_write+0x3d/0x70
    [<c010319c>] sysenter_do_call+0x12/0x38
    [<ffffffff>] 0xffffffff

Any idea? It looks like this is the kmalloc() in fw_realloc_buffer()
(inlined in firmware_data_write).

-- 
Catalin

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