Messages in this thread | | | Date | Tue, 5 Jan 2021 10:48:32 +0800 (GMT+08:00) | From | dinghao.liu@zju ... | Subject | Re: Re: [PATCH] iommu/intel: Fix memleak in intel_irq_remapping_alloc |
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> On 1/3/21 2:22 PM, dinghao.liu@zju.edu.cn wrote: > >> On 2021/1/3 12:08, dinghao.liu@zju.edu.cn wrote: > >>>> Hi, > >>>> > >>>> On 2021/1/2 17:50, Dinghao Liu wrote: > >>>>> When irq_domain_get_irq_data() or irqd_cfg() fails > >>>>> meanwhile i == 0, data allocated by kzalloc() has not > >>>>> been freed before returning, which leads to memleak. > >>>>> > >>>>> Fixes: b106ee63abccb ("irq_remapping/vt-d: Enhance Intel IR driver to support hierarchical irqdomains") > >>>>> Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn> > >>>>> --- > >>>>> drivers/iommu/intel/irq_remapping.c | 2 ++ > >>>>> 1 file changed, 2 insertions(+) > >>>>> > >>>>> diff --git a/drivers/iommu/intel/irq_remapping.c b/drivers/iommu/intel/irq_remapping.c > >>>>> index aeffda92b10b..cdaeed36750f 100644 > >>>>> --- a/drivers/iommu/intel/irq_remapping.c > >>>>> +++ b/drivers/iommu/intel/irq_remapping.c > >>>>> @@ -1354,6 +1354,8 @@ static int intel_irq_remapping_alloc(struct irq_domain *domain, > >>>>> irq_cfg = irqd_cfg(irq_data); > >>>>> if (!irq_data || !irq_cfg) { > >>>>> ret = -EINVAL; > >>>>> + kfree(data); > >>>>> + data = NULL; > >>>> > >>>> Do you need to check (i == 0) here? @data will not be used anymore as it > >>>> goes to out branch, why setting it to NULL here? > >>>> > >>> > >>> data will be passed to ire_data->chip_data when i == 0 and > >>> intel_free_irq_resources() will free it on failure. Thus I > >> > >> Isn't it going to "goto out_free_data"? If "i == 0", the allocated @data > >> won't be freed by intel_free_irq_resources(), hence memory leaking. Does > >> this patch aim to fix this? > >> > >> Best regards, > >> baolu > >> > > > > Correct, this is what I mean. When i > 0, data has been passed to > > irq_data->chip_data, which will be freed in intel_free_irq_resources() > > on failure. So there is no memleak in this case. The memleak only occurs > > on failure when i == 0 (data has not been passed to irq_data->chip_data). > > So how about > > diff --git a/drivers/iommu/intel/irq_remapping.c > b/drivers/iommu/intel/irq_remapping.c > index aeffda92b10b..685200a5cff0 100644 > --- a/drivers/iommu/intel/irq_remapping.c > +++ b/drivers/iommu/intel/irq_remapping.c > @@ -1353,6 +1353,8 @@ static int intel_irq_remapping_alloc(struct > irq_domain *domain, > irq_data = irq_domain_get_irq_data(domain, virq + i); > irq_cfg = irqd_cfg(irq_data); > if (!irq_data || !irq_cfg) { > + if (!i) > + kfree(data); > ret = -EINVAL; > goto out_free_data; > } > > > I set data to NULL after kfree() in this patch to prevent double-free > > when the failure occurs at i > 0. > > if i>0, @data has been passed and will be freed by > intel_free_irq_resources() on the failure path. No need to free or > clear, right?
Right, this is clearer. Thank you for your advice and I will resend a new patch soon.
Regards, Dinghao
> > Best regards, > baolu > > > > > Regards, > > Dinghao > > > >>> set it to NULL to prevent double-free. However, if we add > >>> a check (i == 0) here, we will not need to set it to NULL. > >>> If this is better, I will resend a new patch soon. > >>> > >>> Regards, > >>> Dinghao > >>>
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