From: Chintan Pandya <cpandya@codeaurora.org>
To: akpm@linux-foundation.org
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Chintan Pandya <cpandya@codeaurora.org>
Subject: [PATCH v2] mm: BUG when __kmap_atomic_idx equals KM_TYPE_NR
Date: Thu, 31 Jul 2014 11:54:31 +0530 [thread overview]
Message-ID: <1406787871-2951-1-git-send-email-cpandya@codeaurora.org> (raw)
__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.
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;
}
--
Chintan Pandya
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a
member of the Code Aurora Forum, hosted by The Linux Foundation
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next reply other threads:[~2014-07-31 6:24 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-31 6:24 Chintan Pandya [this message]
2014-07-31 7:02 ` [PATCH v2] mm: BUG when __kmap_atomic_idx equals KM_TYPE_NR David Rientjes
2014-07-31 9:28 ` Chintan Pandya
2014-07-31 22:45 ` Andrew Morton
2014-08-04 9:25 ` Chintan Pandya
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