linux-kernel - Re: Possible memory leak in request

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Message-ID: <d82e647a0907080142q65a044aeie50048cba2ac636a@mail.gmail.com>
Date:	Wed, 8 Jul 2009 16:42:30 +0800
From:	Ming Lei <tom.leiming@...il.com>
To:	David Woodhouse <dwmw2@...radead.org>
Cc:	Catalin Marinas <catalin.marinas@....com>,
	Cornelia Huck <cornelia.huck@...ibm.com>,
	Greg Kroah-Hartman <gregkh@...e.de>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	Sachin Sant <sachinp@...ibm.com>
Subject: Re: Possible memory leak in request_firmware()

2009/7/8 David Woodhouse <dwmw2@...radead.org>:
> On Wed, 2009-07-08 at 12:38 +0800, Ming Lei wrote:
>> 2009/7/8 Catalin Marinas <catalin.marinas@....com>:
>> > On Tue, 2009-07-07 at 19:01 +0200, Cornelia Huck wrote:
>> >
>> > 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).
>>
>> I guess the leak is introduced in commit :
>>              commit   6e03a201bbe8137487f340d26aa662110e324b20
>>              firmware: speed up request_firmware(), v3
>>
>> The attachment patch may fix the leak, please test and verify it.
>> Thanks.
>
> I think you need to stop it from clearing fw_priv->nr_pages too.
> With that change, it looks correct. Thanks.

IMHO, No.
If nr_pages is not cleaned, pages pointed by pages[] will be freed
by fw_dev_release, but they should be freed by vfree()
in release_firmware. Right?

>
> Acked-by: David Woodhouse <David.Woodhouse@...el.com>




-- 
Lei Ming
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