Messages in this thread | | | Subject | Re: [PATCH -next] scsi: hisi_sas: drop free_irq of devm_request_irq allocated irq | From | John Garry <> | Date | Wed, 19 May 2021 12:19:09 +0100 |
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On 19/05/2021 04:36, Yang Yingliang wrote: > > 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@huawei.com> >>> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> >>> --- >>> 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.
So I think that we need this addition: devm_free_irq(&pdev->dev, pci_irq_vector(pdev, nr), cq);
>> >> 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.
Kasan doesn't complain. Anyway, I think we can't rely on device-managed method (for calling free_irq()) as it conflicts with pci free vectors call. I thought that someone was developed a device-managed version of that (pci_alloc_irq_vectors()).
Anyway, please proceed with your change, but with the suggested addition.
Thanks
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