Re: MdeModulePkg/UefiBootManagerLib: recursive call of BmRepairAllControllers

[Guo Heyi <heyi.guo@linaro.org>]

Sure.

On Sat, Feb 24, 2018 at 08:40:20AM +0000, Ni, Ruiyu wrote:
> Will you submit a patch for this change?
> 
> Thanks/Ray
> 
> > -----Original Message-----
> > From: Guo Heyi [mailto:heyi.guo@linaro.org]
> > Sent: Saturday, February 24, 2018 4:29 PM
> > To: Ni, Ruiyu <ruiyu.ni@intel.com>
> > Cc: Guo Heyi <heyi.guo@linaro.org>; edk2-devel@lists.01.org; Zeng, Star
> > <star.zeng@intel.com>; Dong, Eric <eric.dong@intel.com>
> > Subject: Re: MdeModulePkg/UefiBootManagerLib: recursive call of
> > BmRepairAllControllers
> > 
> > On Sat, Feb 24, 2018 at 04:20:52PM +0800, Ni, Ruiyu wrote:
> > > On 2/24/2018 2:23 PM, Guo Heyi wrote:
> > > >Hi folks,
> > > >
> > > >In BmDriverHealth.c, function BmRepairAllControllers may recursively
> > > >call itself if some driver health protocol returns
> > EfiDriverHealthStatusReconnectRequired.
> > > >However, if there is something wrong in some 3rd party driver (e.g.
> > > >PCI oprom), the driver health protocol of that 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.
> > >
> > > yes. I agree.
> > > If a buggy PCI oprom always return ReconnectRequired, the stack
> > > overflow will happen.
> > >
> > > How about we choose maximum recursive call depth as 10 and continue to
> > > boot if call depth reaches 11?
> > 
> > That's fine for me :)
> > 
> > Thanks,
> > 
> > Gary (Heyi Guo)
> > 
> > >
> > > >
> > > >So does it make sense to set a maximum count of this recursive call
> > > >to avoid whole system hang even there is a buggy 3rd party driver?
> > > >
> > > >Thanks,
> > > >
> > > >Gary (Heyi Guo)
> > > >
> > >
> > >
> > > --
> > > Thanks,
> > > Ray