Re: [PATCH] mm: BUG when __kmap_atomic_idx crosses boundary

From: Andrew Morton
Date: Wed Jul 30 2014 - 05:04:00 EST


On Wed, 30 Jul 2014 14:22:35 +0530 Chintan Pandya <cpandya@xxxxxxxxxxxxxx> wrote:

> __kmap_atomic_idx >= KM_TYPE_NR or < ZERO is a bug.
> Report it even if CONFIG_DEBUG_HIGHMEM is not enabled.
> That saves much debugging efforts.

Please take considerably more care when preparing patch changelogs.

kmap_atomic() is a very commonly called function so we'll need much
more detail than this to justify adding overhead to it.

I don't think CONFIG_DEBUG_HIGHMEM really needs to exist. We could do
s/CONFIG_DEBUG_HIGHMEM/CONFIG_DEBUG_VM/g and perhaps your secret bug
whatever it was would have been found more easily.

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