Messages in this thread | | | From | "Winiarska, Iwona" <> | Subject | Re: [PATCH] peci: fix potential memory leak in devm_adev_add() | Date | Tue, 5 Jul 2022 10:18:51 +0000 |
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On Mon, 2022-07-04 at 20:59 +0800, Jianglei Nie wrote: > devm_adev_add() allocates a memory chunk for "adev" and "adev->name" > with adev_alloc(). When auxiliary_device_add() fails, the function calls > auxiliary_device_uninit(), which doesn't release the allocated "adev" > and "adev->name", thus leading to a memory leak bug. > > We should call adev_release() instead of auxiliary_device_uninit() to > release the "adev" and "adev->name". > > Signed-off-by: Jianglei Nie <niejianglei2021@163.com> > --- > drivers/peci/cpu.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/peci/cpu.c b/drivers/peci/cpu.c > index 68eb61c65d34..de865997ccde 100644 > --- a/drivers/peci/cpu.c > +++ b/drivers/peci/cpu.c > @@ -248,7 +248,7 @@ static int devm_adev_add(struct device *dev, int idx) > > ret = auxiliary_device_add(adev); > if (ret) { > - auxiliary_device_uninit(adev); > + adev_release(&adev->dev); > return ret; > } >
When we call auxiliary_device_uninit() the .release callback (adev_release()) will be triggered, so there's no memory leak here.
But thank you for pointing to this - it made me realize that we have a bug in adev_release(), because we call auxiliary_device_uninit() there, which will cause a use-after-free with refcount underflow in this case.
I'd appreciate if you could review it: https://lore.kernel.org/lkml/20220705101501.298395-1-iwona.winiarska@intel.com/
Thanks -Iwona
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