Messages in this thread | | | Date | Thu, 31 Jul 2014 00:02:38 -0700 (PDT) | From | David Rientjes <> | Subject | Re: [PATCH v2] mm: BUG when __kmap_atomic_idx equals KM_TYPE_NR |
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On Thu, 31 Jul 2014, Chintan Pandya wrote:
> __kmap_atomic_idx is per_cpu variable. Each CPU can > use KM_TYPE_NR entries from FIXMAP i.e. from 0 to > KM_TYPE_NR - 1. Allowing __kmap_atomic_idx to over- > shoot to KM_TYPE_NR can mess up with next CPU's 0th > entry which is a bug. Hence BUG_ON if > __kmap_atomic_idx >= KM_TYPE_NR. >
This appears to be a completely different patch, not a v2. Why is this check only done for CONFIG_DEBUG_HIGHMEM?
I think Andrew's comment earlier was referring to the changelog only and not the patch, which looked correct.
> Signed-off-by: Chintan Pandya <cpandya@codeaurora.org> > --- > Changes: > > V1 --> V2 > > Not touching CONFIG_DEBUG_HIGHMEM. > > include/linux/highmem.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/highmem.h b/include/linux/highmem.h > index 7fb31da..9286a46 100644 > --- a/include/linux/highmem.h > +++ b/include/linux/highmem.h > @@ -93,7 +93,7 @@ static inline int kmap_atomic_idx_push(void) > > #ifdef CONFIG_DEBUG_HIGHMEM > WARN_ON_ONCE(in_irq() && !irqs_disabled()); > - BUG_ON(idx > KM_TYPE_NR); > + BUG_ON(idx >= KM_TYPE_NR); > #endif > return idx; > }
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