Re: [PATCH 1/1] MdeModulePkg/UefiBootManagerLib: limit recursive call depth

["Ni, Ruiyu" <ruiyu.ni@Intel.com>]

On 3/1/2018 10:39 AM, Heyi Guo wrote:
> Function BmRepairAllControllers may recursively call itself if some
> driver health protocol returns EfiDriverHealthStatusReconnectRequired.
> However, driver health protocol of some buggy third party driver may
> always return such status even after one and another reconnect. The
> endless iteration will cause stack overflow and then system exception,
> and it may be not easy to find that the exception is actually caused
> by stack overflow.
> 
> So we limit the number of reconnect retry to 10 to improve code
> robustness, and DEBUG_CODE is moved ahead before recursive repair to
> track the repair result.
> 
> We also remove a duplicated declaration of BmRepairAllControllers() in
> InternalBm.h in this patch, for it is only a trivial change.
> 
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Heyi Guo <heyi.guo@linaro.org>
> Cc: Star Zeng <star.zeng@intel.com>
> Cc: Eric Dong <eric.dong@intel.com>
> Cc: Ruiyu Ni <ruiyu.ni@intel.com>
> Cc: Laszlo Ersek <lersek@redhat.com>
> ---
> 
> Notes:
>      v2
>      - Use argument instead of global variable to record the recursive
>        count [Ray]
>      - Move DEBUG_CODE before recursively calling BmRepairAllControllers()
>        to track the change of each reconnect [Ray]
>      - Remove a duplicated declaration of BmRepairAllControllers() in
>        InternalBm.h.
> 
>   MdeModulePkg/Library/UefiBootManagerLib/InternalBm.h     | 19 ++++++++++---------
>   MdeModulePkg/Library/UefiBootManagerLib/BmBoot.c         |  2 +-
>   MdeModulePkg/Library/UefiBootManagerLib/BmDriverHealth.c | 18 +++++++++++++-----
>   3 files changed, 24 insertions(+), 15 deletions(-)
> 
> diff --git a/MdeModulePkg/Library/UefiBootManagerLib/InternalBm.h b/MdeModulePkg/Library/UefiBootManagerLib/InternalBm.h
> index 25a1d522fe84..21ecd8584d24 100644
> --- a/MdeModulePkg/Library/UefiBootManagerLib/InternalBm.h
> +++ b/MdeModulePkg/Library/UefiBootManagerLib/InternalBm.h
> @@ -108,6 +108,12 @@ CHAR16 *
>   #define BM_OPTION_NAME_LEN                          sizeof ("PlatformRecovery####")
>   extern CHAR16  *mBmLoadOptionName[];
>   
> +//
> +// Maximum number of reconnect retry to repair controller; it is to limit the
> +// number of recursive call of BmRepairAllControllers.
> +//
> +#define MAX_RECONNECT_REPAIR                        10
> +
>   /**
>     Visitor function to be called by BmForEachVariable for each variable
>     in variable storage.
> @@ -145,10 +151,13 @@ typedef struct {
>   
>   /**
>     Repair all the controllers according to the Driver Health status queried.
> +
> +  @param ReconnectRepairCount     To record the number of recursive call of
> +                                  this function itself.
>   **/
>   VOID
>   BmRepairAllControllers (
> -  VOID
> +  UINTN       ReconnectRepairCount
>     );
>   
>   #define BM_HOTKEY_SIGNATURE SIGNATURE_32 ('b', 'm', 'h', 'k')
> @@ -328,14 +337,6 @@ BmDelPartMatchInstance (
>     );
>   
>   /**
> -  Repair all the controllers according to the Driver Health status queried.
> -**/
> -VOID
> -BmRepairAllControllers (
> -  VOID
> -  );
> -
> -/**
>     Print the device path info.
>   
>     @param DevicePath           The device path need to print.
> diff --git a/MdeModulePkg/Library/UefiBootManagerLib/BmBoot.c b/MdeModulePkg/Library/UefiBootManagerLib/BmBoot.c
> index ce19ae400660..b842d5824aed 100644
> --- a/MdeModulePkg/Library/UefiBootManagerLib/BmBoot.c
> +++ b/MdeModulePkg/Library/UefiBootManagerLib/BmBoot.c
> @@ -1767,7 +1767,7 @@ EfiBootManagerBoot (
>       //
>       // 4. Repair system through DriverHealth protocol
>       //
> -    BmRepairAllControllers ();
> +    BmRepairAllControllers (0);
>     }
>   
>     PERF_START_EX (gImageHandle, "BdsAttempt", NULL, 0, (UINT32) OptionNumber);
> diff --git a/MdeModulePkg/Library/UefiBootManagerLib/BmDriverHealth.c b/MdeModulePkg/Library/UefiBootManagerLib/BmDriverHealth.c
> index ddcee8b0676f..db2f859ae73d 100644
> --- a/MdeModulePkg/Library/UefiBootManagerLib/BmDriverHealth.c
> +++ b/MdeModulePkg/Library/UefiBootManagerLib/BmDriverHealth.c
> @@ -423,10 +423,13 @@ EfiBootManagerFreeDriverHealthInfo (
>   
>   /**
>     Repair all the controllers according to the Driver Health status queried.
> +
> +  @param ReconnectRepairCount     To record the number of recursive call of
> +                                  this function itself.
>   **/
>   VOID
>   BmRepairAllControllers (
> -  VOID
> +  UINTN       ReconnectRepairCount
>     )
>   {
>     EFI_STATUS                          Status;
> @@ -548,10 +551,6 @@ BmRepairAllControllers (
>     EfiBootManagerFreeDriverHealthInfo (DriverHealthInfo, Count);
>   
>   
> -  if (ReconnectRequired) {
> -    BmRepairAllControllers ();
> -  }
> -
>     DEBUG_CODE (
>       CHAR16 *ControllerName;
>   
> @@ -576,6 +575,15 @@ BmRepairAllControllers (
>       EfiBootManagerFreeDriverHealthInfo (DriverHealthInfo, Count);
>       );
>   
> +  if (ReconnectRequired) {
> +    if (ReconnectRepairCount < MAX_RECONNECT_REPAIR) {
> +      BmRepairAllControllers (ReconnectRepairCount + 1);
> +    } else {
> +      DEBUG ((DEBUG_ERROR, "[%a:%d] Repair failed after %d retries.\n",
> +        __FUNCTION__, __LINE__, ReconnectRepairCount));
> +    }
> +  }
> +
>     if (RebootRequired) {
>       DEBUG ((EFI_D_INFO, "[BDS] One of the Driver Health instances requires rebooting.\n"));
>       gRT->ResetSystem (EfiResetWarm, EFI_SUCCESS, 0, NULL);
> 
Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>

-- 
Thanks,
Ray