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 >=
KM_TYPE_NR.

Fix the off-by-on in this test.
Signed-off-by: default avatarChintan Pandya <cpandya@codeaurora.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit 1d352bfd41e8219cdf9bebe79677700bdc38b540)
parent e182d1b3
......@@ -101,7 +101,7 @@ 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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