Messages in this thread | | | From | Alan Mikhak <> | Date | Tue, 25 Jun 2019 10:27:08 -0700 | Subject | Re: [PATCH] nvme-pci: Avoid leak if pci_p2pmem_virt_to_bus() returns null |
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On Tue, Jun 25, 2019 at 12:09 AM Christoph Hellwig <hch@lst.de> wrote: > > On Mon, Jun 24, 2019 at 04:57:22PM -0700, Alan Mikhak wrote: > > Modify nvme_alloc_sq_cmds() to call pci_free_p2pmem() > > to free the memory it allocated using pci_alloc_p2pmem() > > in case pci_p2pmem_virt_to_bus() returns null. > > > > Make sure not to call pci_free_p2pmem() if pci_alloc_p2pmem() > > returned null which can happen if CONFIG_PCI_P2PDMA is not > > configured. > > Can you >
I mean this patch makes sure not to call pci_free_p2pmem() if nothing was allocated by pci_alloc_p2pmem().
> > > > Signed-off-by: Alan Mikhak <alan.mikhak@sifive.com> > > --- > > drivers/nvme/host/pci.c | 14 +++++++++----- > > 1 file changed, 9 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c > > index 524d6bd6d095..5dfa067f6506 100644 > > --- a/drivers/nvme/host/pci.c > > +++ b/drivers/nvme/host/pci.c > > @@ -1456,11 +1456,15 @@ static int nvme_alloc_sq_cmds(struct nvme_dev *dev, struct nvme_queue *nvmeq, > > > > if (qid && dev->cmb_use_sqes && (dev->cmbsz & NVME_CMBSZ_SQS)) { > > nvmeq->sq_cmds = pci_alloc_p2pmem(pdev, SQ_SIZE(depth)); > > - nvmeq->sq_dma_addr = pci_p2pmem_virt_to_bus(pdev, > > - nvmeq->sq_cmds); > > - if (nvmeq->sq_dma_addr) { > > - set_bit(NVMEQ_SQ_CMB, &nvmeq->flags); > > - return 0; > > + if (nvmeq->sq_cmds) { > > + nvmeq->sq_dma_addr = pci_p2pmem_virt_to_bus(pdev, > > + nvmeq->sq_cmds); > > + if (nvmeq->sq_dma_addr) { > > + set_bit(NVMEQ_SQ_CMB, &nvmeq->flags); > > + return 0; > > + } > > + > > + pci_free_p2pmem(pdev, nvmeq->sq_cmds, SQ_SIZE(depth)); > > pci_p2pmem_virt_to_bus should only fail when > pci_p2pmem_virt_to_bus failed. That being said I think doing the > error check on pci_alloc_p2pmem instead of relying on > pci_p2pmem_virt_to_bus "passing through" the error seems odd, I'd > rather check the pci_alloc_p2pmem return value directly.
Thanks Christoph. I could see the existing code should not leak but only after inspecting pci_p2pmem_virt_to_bus() and gen_pool_virt_to_phys(). I wondered what if these functions changed and broke the relation but that seems unlikely. Checking the return value directly may require less from the reader, if that's a good outcome.
Alan
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