Re: [PATCH 1/2] crypto: thunderx_zip: Fix fallout from CONFIG_VMAP_STACK

[Jan Glauber <jan.glauber@caviumnetworks.com>]

On Wed, Mar 28, 2018 at 03:05:56PM +0200, Jan Glauber wrote:
> Enabling virtual mapped kernel stacks breaks the thunderx_zip
> driver. On compression or decompression the executing CPU hangs
> in an endless loop. The reason for this is the usage of __pa
> by the driver which does no longer work for an address that is
> not part of the 1:1 mapping.
> 
> The zip driver allocates a result struct on the stack and needs
> to tell the hardware the physical address within this struct
> that is used to signal the completion of the request.
> 
> As the hardware gets the wrong address after the broken __pa
> conversion it writes to an arbitrary address. The zip driver then
> waits forever for the completion byte to contain a non-zero value.
> 
> Allocating the result struct from 1:1 mapped memory resolves this
> bug.

Hi Herbert,

Just realized that we might sleep in this path, so GFP_KERNEL wont
work here. Same with usleep in the second patch.

I'll respin the patches.

--Jan


> Signed-off-by: Jan Glauber <jglauber@cavium.com>
> Reviewed-by: Robert Richter <rrichter@cavium.com>
> Cc: stable <stable@vger.kernel.org> # 4.14
> ---
>  drivers/crypto/cavium/zip/zip_crypto.c | 22 ++++++++++++++--------
>  1 file changed, 14 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/crypto/cavium/zip/zip_crypto.c b/drivers/crypto/cavium/zip/zip_crypto.c
> index 8df4d26..2fc9b03 100644
> --- a/drivers/crypto/cavium/zip/zip_crypto.c
> +++ b/drivers/crypto/cavium/zip/zip_crypto.c
> @@ -124,7 +124,7 @@ int zip_compress(const u8 *src, unsigned int slen,
>                  struct zip_kernel_ctx *zip_ctx)
>  {
>         struct zip_operation  *zip_ops   = NULL;
> -       struct zip_state      zip_state;
> +       struct zip_state      *zip_state;
>         struct zip_device     *zip = NULL;
>         int ret;
> 
> @@ -135,20 +135,23 @@ int zip_compress(const u8 *src, unsigned int slen,
>         if (!zip)
>                 return -ENODEV;
> 
> -       memset(&zip_state, 0, sizeof(struct zip_state));
> +       zip_state = kzalloc(sizeof(*zip_state), GFP_KERNEL);
> +       if (!zip_state)
> +               return -ENOMEM;
> +
>         zip_ops = &zip_ctx->zip_comp;
> 
>         zip_ops->input_len  = slen;
>         zip_ops->output_len = *dlen;
>         memcpy(zip_ops->input, src, slen);
> 
> -       ret = zip_deflate(zip_ops, &zip_state, zip);
> +       ret = zip_deflate(zip_ops, zip_state, zip);
> 
>         if (!ret) {
>                 *dlen = zip_ops->output_len;
>                 memcpy(dst, zip_ops->output, *dlen);
>         }
> -
> +       kfree(zip_state);
>         return ret;
>  }
> 
> @@ -157,7 +160,7 @@ int zip_decompress(const u8 *src, unsigned int slen,
>                    struct zip_kernel_ctx *zip_ctx)
>  {
>         struct zip_operation  *zip_ops   = NULL;
> -       struct zip_state      zip_state;
> +       struct zip_state      *zip_state;
>         struct zip_device     *zip = NULL;
>         int ret;
> 
> @@ -168,7 +171,10 @@ int zip_decompress(const u8 *src, unsigned int slen,
>         if (!zip)
>                 return -ENODEV;
> 
> -       memset(&zip_state, 0, sizeof(struct zip_state));
> +       zip_state = kzalloc(sizeof(*zip_state), GFP_KERNEL);
> +       if (!zip_state)
> +               return -ENOMEM;
> +
>         zip_ops = &zip_ctx->zip_decomp;
>         memcpy(zip_ops->input, src, slen);
> 
> @@ -179,13 +185,13 @@ int zip_decompress(const u8 *src, unsigned int slen,
>         zip_ops->input_len  = slen;
>         zip_ops->output_len = *dlen;
> 
> -       ret = zip_inflate(zip_ops, &zip_state, zip);
> +       ret = zip_inflate(zip_ops, zip_state, zip);
> 
>         if (!ret) {
>                 *dlen = zip_ops->output_len;
>                 memcpy(dst, zip_ops->output, *dlen);
>         }
> -
> +       kfree(zip_state);
>         return ret;
>  }
> 
> --
> 2.7.4