Re: [PATCH] acpi, nfit: fix register dimm error handling

[Dan Williams]

On Fri, Feb 2, 2018 at 1:00 PM, Toshi Kani <toshi.kani@xxxxxxx> wrote:
> A NULL pointer reference kernel bug was observed when
> acpi_nfit_add_dimm() called in acpi_nfit_register_dimms()
> failed. This error path does not set nfit_mem->nvdimm, but
> the 2nd list_for_each_entry() loop in the function assumes
> it's always set. Add a check to nfit_mem->nvdimm.
>
> Signed-off-by: Toshi Kani <toshi.kani@xxxxxxx>
> Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
> Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
> ---
>  drivers/acpi/nfit/core.c |    3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
> index abeb4df4f22e..b28ce440a06f 100644
> --- a/drivers/acpi/nfit/core.c
> +++ b/drivers/acpi/nfit/core.c
> @@ -1867,6 +1867,9 @@ static int acpi_nfit_register_dimms(struct acpi_nfit_desc *acpi_desc)
>                 struct kernfs_node *nfit_kernfs;
>
>                 nvdimm = nfit_mem->nvdimm;
> +               if (!nvdimm)
> +                       continue;
> +
>                 nfit_kernfs = sysfs_get_dirent(nvdimm_kobj(nvdimm)->sd, "nfit");
>                 if (nfit_kernfs)
>                         nfit_mem->flags_attr = sysfs_get_dirent(nfit_kernfs,

Yes, I assume this also needs:

Cc: <stable@xxxxxxxxxxxxxxx>
Fixes: ba9c8dd3c222 ("acpi, nfit: add dimm device notification support")