Re:

Mauro Carvalho Chehab
2012-08-09T17:29:12Z

Hi Fengguang,

Em 09-08-2012 10:54, Fengguang Wu escreveu:
...
> Date: Thu, 9 Aug 2012 21:54:16 +0800
> From: Fengguang Wu <fengguang.wu@intel.com>
> To: Mauro Carvalho Chehab <mchehab@redhat.com>
> Cc: Dave Peterson <dsp@llnl.gov>, kernel-janitors@vger.kernel.org,
> Doug Thompson <dougthompson@xmission.com>, linux-edac@vger.kernel.org,
> linux-kernel@vger.kernel.org
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> Subject: possible double free in edac_mc_alloc()
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There is an extra space between the email headers and the Subject...
due to that I almost deleted this message, considering it as spam.

>
> Hi,
>
> coccinelle warns about:
>
> + drivers/edac/edac_mc.c:429:9-23: ERROR: reference preceded by free on line 429
>
> and that line does look strange: the 'i' seems like a temporary value
> used in previous loops, and it won't change at all in the current
> loop. Which means the same mci->csrows[i] get freed once and again.
> It might also do double free for the previous kfree(csr) line.
>
> vim +429 drivers/edac/edac_mc.c
>
> 416 if (mci->dimms) {
> 417 for (i = 0; i < tot_dimms; i++)
> 418 kfree(mci->dimms[i]);
> 419 kfree(mci->dimms);
> 420 }
> 421 if (mci->csrows) {
> 422 for (chn = 0; chn < tot_channels; chn++) {
> 423 csr = mci->csrows[chn];
> 424 if (csr) {
> 425 for (chn = 0; chn < tot_channels; chn++)
> 426 kfree(csr->channels[chn]);
> 427 kfree(csr);
> 428 }
> > 429 kfree(mci->csrows[i]);

It should likely be:
kfree(mci->csrows[csr])
instead. This is likely due to one of the countless rebases I had to do on it,
in order to make everybody happy. I suspect that, in the past, this loop was also
using 'i' as the index variable.

Care to write us a patch fixing it? My HD crashed yesterday... I'm somewhat
busy today recovering from it, and doing some backup/restore stuff.

Thanks!
Mauro

> 430 }
> 431 kfree(mci->csrows);
> 432 }
>
> ---
> 0-DAY kernel build testing backend Open Source Technology Centre
> Fengguang Wu <wfg@linux.intel.com> Intel Corporation
>