RE: Re：Re: [PATCH] powerpc: Fix a bug in __div64_32 if divisor is zero

[David Laight]

From: Guohua Zhong
> Sent: 24 August 2020 14:26
> 
> >> >In generic version in lib/math/div64.c, there is no checking of 'base'
> >> >either.
> >> >Do we really want to add this check in the powerpc version only ?
> >>
> >> >The only user of __div64_32() is do_div() in
> >> >include/asm-generic/div64.h. Wouldn't it be better to do the check there ?
> >>
> >> >Christophe
> >>
> >> Yet, I have noticed that there is no checking of 'base' in these functions.
> >> But I am not sure how to check is better.As we know that the result is
> >> undefined when divisor is zero. It maybe good to print error and dump stack.

I thought that the onus was put on the caller to avoid divide by zero.

On x86 divide by zero causes an exception which (I'm pretty sure)
leads to a oops/panic.

	David

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