Commit c79ac9a3 authored by Chintan Pandya's avatar Chintan Pandya Committed by Bernhard Thoben
Browse files

mm: BUG when __kmap_atomic_idx equals KM_TYPE_NR

__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 >=

Fix the off-by-on in this test.
Signed-off-by: default avatarChintan Pandya <>
Cc: David Rientjes <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
(cherry picked from commit 1d352bfd41e8219cdf9bebe79677700bdc38b540)
parent e182d1b3
......@@ -101,7 +101,7 @@ static inline int kmap_atomic_idx_push(void)
WARN_ON_ONCE(in_irq() && !irqs_disabled());
BUG_ON(idx >= KM_TYPE_NR);
return idx;
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