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SubjectRe: [PATCH] drivers/macintosh: Correct potential double free
FromBenjamin Herrenschmidt <>
DateMon, 29 Mar 2010 21:57:15 +1100
On Mon, 2010-03-29 at 11:39 +0200, Julia Lawall wrote:
> From: Julia Lawall <julia@diku.dk>
>
> The conditionals were testing different values, but then all freeing the
> same one, which could result in a double free.
>
> A simplified version of the semantic match that finds this problem is as
> follows: (http://coccinelle.lip6.fr/)

Thanks. I'll stick that in my -next branch as soon as I open it :-)

Cheers,
Ben.

> // <smpl>
> @@
> expression x,e;
> identifier f;
> iterator I;
> statement S;
> @@
>
> *kfree(x);
> ... when != &x
> when != x = e
> when != I(x,...) S
> *x
> // </smpl>
>
> Signed-off-by: Julia Lawall <julia@diku.dk>
>
> ---
> drivers/macintosh/windfarm_pm91.c | 9 +++------
> 1 files changed, 3 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/macintosh/windfarm_pm91.c b/drivers/macintosh/windfarm_pm91.c
> index bea9916..3442732 100644
> --- a/drivers/macintosh/windfarm_pm91.c
> +++ b/drivers/macintosh/windfarm_pm91.c
> @@ -687,12 +687,9 @@ static int __devexit wf_smu_remove(struct platform_device *ddev)
> wf_put_control(cpufreq_clamp);
>
> /* Destroy control loops state structures */
> - if (wf_smu_slots_fans)
> - kfree(wf_smu_cpu_fans);
> - if (wf_smu_drive_fans)
> - kfree(wf_smu_cpu_fans);
> - if (wf_smu_cpu_fans)
> - kfree(wf_smu_cpu_fans);
> + kfree(wf_smu_slots_fans);
> + kfree(wf_smu_drive_fans);
> + kfree(wf_smu_cpu_fans);
>
> return 0;
> }




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