linux-kernel - Re: [PATCH 1/3] intel_sgx: do not use BUG() in sgx_free

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Date:   Fri, 27 Jan 2017 17:45:03 +0200
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
Cc:     intel-sgx-kernel-dev@...ts.01.org,
        Darren Hart <dvhart@...radead.org>,
        "open list:X86 PLATFORM DRIVERS" 
        <platform-driver-x86@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/3] intel_sgx: do not use BUG() in sgx_free_page()

On Thu, Jan 26, 2017 at 11:20 PM, Jarkko Sakkinen
<jarkko.sakkinen@...ux.intel.com> wrote:
> EREMOVE fails on non-EPC page or when a SECS page with children is to be
> removed. These do not happen if the driver is working correctly. Log the
> error but do not crash the driver.
>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
> ---
>  drivers/platform/x86/intel_sgx_page_cache.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/platform/x86/intel_sgx_page_cache.c b/drivers/platform/x86/intel_sgx_page_cache.c
> index d073057..7f73ac7 100644
> --- a/drivers/platform/x86/intel_sgx_page_cache.c
> +++ b/drivers/platform/x86/intel_sgx_page_cache.c
> @@ -551,10 +551,8 @@ void sgx_free_page(struct sgx_epc_page *entry,
>                 ret = __eremove(epc);
>                 sgx_put_epc_page(epc);
>
> -               if (ret) {
> -                       pr_err("EREMOVE returned %d\n", ret);
> -                       BUG();
> -               }
> +               if (ret)
> +                       sgx_err(encl, "EREMOVE returned %d\n", ret);

Do you have something like critical level? For me seems reasonable to
increase the level of message if BUG() was somehow related to actual
situation.

>         }
>
>         spin_lock(&sgx_free_list_lock);

-- 
With Best Regards,
Andy Shevchenko