Re: [PATCH] fork_init: fix division by zero

From: Al Viro
Date: Wed Dec 10 2008 - 05:17:57 EST


On Wed, Dec 10, 2008 at 01:01:13PM +0300, Yuri Tikhonov wrote:

> >> + max_threads = mempages * PAGE_SIZE / (8 * THREAD_SIZE);
> > ^^^^^^^^^^^^^^^^^^^^
> >> +#endif
>
> > Can't this overflow, e.g. on 32-bit machines with HIGHMEM?
>
> The multiplier here is not PAGE_SIZE, but [PAGE_SIZE / (8 *
> THREAD_SIZE)], and this value is expected to be rather small (2, 4, or
> so).

x * y / z is parsed as (x * y) / z, not x * (y / z).

Only assignment operators (and ?:, in a sense that a ? b : c ? d : e is
parsed as a ? b : (c ? d : e)) are right-to-left. The rest is left-to-right.
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