[PATCH] nvme-pci: fix NULL pointer dereference in nvme_free_host_mem()
Minwoo Im
minwoo.im.dev at gmail.com
Thu Nov 30 06:37:52 PST 2017
On Sat, Nov 25, 2017 at 3:03 AM, Minwoo Im <minwoo.im.dev at gmail.com> wrote:
> Following condition which will cause NULL pointer dereference will
> occur in nvme_free_host_mem() when it tries to remove pci device via
> nvme_remove() especially after a failure of host memory allocation for HMB.
>
> "(host_mem_descs == NULL) && (nr_host_mem_descs != 0)"
>
> It's because __nr_host_mem_descs__ is not cleared to 0 unlike
> __host_mem_descs__ is so.
>
> Signed-off-by: Minwoo Im <minwoo.im.dev at gmail.com>
> ---
> drivers/nvme/host/pci.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
> index 6173747..f5800c3 100644
> --- a/drivers/nvme/host/pci.c
> +++ b/drivers/nvme/host/pci.c
> @@ -1759,6 +1759,7 @@ static void nvme_free_host_mem(struct nvme_dev *dev)
> dev->nr_host_mem_descs * sizeof(*dev->host_mem_descs),
> dev->host_mem_descs, dev->host_mem_descs_dma);
> dev->host_mem_descs = NULL;
> + dev->nr_host_mem_descs = 0;
> }
>
> static int __nvme_alloc_host_mem(struct nvme_dev *dev, u64 preferred,
> --
> 2.7.4
>
Hi Christoph,
I saw a commit (7e5dd57ef3081ff6c03908d786ed5087f6fbb7ae) for this
patch on nvme-4.15.
Thanks to you for picking it up.
Is there anything I missed or need to know about "freeing host memory"?
Thanks,
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