Re: [PATCH -next] scsi: hisi_sas: drop free_irq of devm_request_irq allocated irq

[Yang Yingliang]

On 2021/5/18 23:34, John Garry wrote:
> On 18/05/2021 14:09, Yang Yingliang wrote:
> > irq allocated with devm_request_irq should not be freed using
> > free_irq, because doing so causes a dangling pointer, and a
> > subsequent double free.
> >
> > Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
> > Signed-off-by: Yang Yingliang <yangyingliang@xxxxxxxxxx>
> > ---
> >   drivers/scsi/hisi_sas/hisi_sas_v3_hw.c | 6 +++---
> >   1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c 
> > b/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
> > index 499c770d405c..684f762bcfb3 100644
> > --- a/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
> > +++ b/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
> > @@ -4811,9 +4811,9 @@ hisi_sas_v3_destroy_irqs(struct pci_dev *pdev, 
> > struct hisi_hba *hisi_hba)
> >   {
> >       int i;
> >   -    free_irq(pci_irq_vector(pdev, 1), hisi_hba);
> > -    free_irq(pci_irq_vector(pdev, 2), hisi_hba);
> > -    free_irq(pci_irq_vector(pdev, 11), hisi_hba);
> > +    devm_free_irq(&pdev->dev, pci_irq_vector(pdev, 1), hisi_hba);
> > +    devm_free_irq(&pdev->dev, pci_irq_vector(pdev, 2), hisi_hba);
> > +    devm_free_irq(&pdev->dev, pci_irq_vector(pdev, 11), hisi_hba);
> >       for (i = 0; i < hisi_hba->cq_nvecs; i++) {
> >           struct hisi_sas_cq *cq = &hisi_hba->cq[i];
> >           int nr = hisi_sas_intr_conv ? 16 : 16 + i;
>
> Does the free_irq(pci_irq_vector(pdev, nr, cq)) call also need to 
> change (not shown)?
Yes, I missed that, it should be changed too.
> Having said that, why have these at all if we use devm_request_irq()? 
> devm_irq_release() calls free_irq().
I keep the original logic here, only avoid double free.
> Thanks,
> John
>
> .