linux-kernel - [PATCH] mm/highmem: Fix CONFIG_DEBUG_KMAP_LOCAL_FORCE

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Date:   Thu, 18 Mar 2021 16:06:57 -0700
From:   ira.weiny@...el.com
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     Ira Weiny <ira.weiny@...el.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Oliver Sang <oliver.sang@...el.com>,
        Chaitanya Kulkarni <Chaitanya.Kulkarni@....com>,
        David Sterba <dsterba@...e.com>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] mm/highmem: Fix CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP

From: Ira Weiny <ira.weiny@...el.com>

The kernel test robot found that __kmap_local_sched_out() was not
correctly skipping the guard pages when
CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP was set.[1]  This was due to
CONFIG_DEBUG_HIGHMEM check being used.

Change the configuration check to be correct.

[1] https://lore.kernel.org/lkml/20210304083825.GB17830@xsang-OptiPlex-9020/

Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Oliver Sang <oliver.sang@...el.com>
Cc: Chaitanya Kulkarni <Chaitanya.Kulkarni@....com>
Cc: David Sterba <dsterba@...e.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Fixes: 0e91a0c6984c ("mm/highmem: Provide CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP")
Reported-by: kernel test robot <oliver.sang@...el.com>
Signed-off-by: Ira Weiny <ira.weiny@...el.com>
---
 mm/highmem.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/highmem.c b/mm/highmem.c
index 86f2b9495f9c..6ef8f5e05e7e 100644
--- a/mm/highmem.c
+++ b/mm/highmem.c
@@ -618,7 +618,7 @@ void __kmap_local_sched_out(void)
 		int idx;
 
 		/* With debug all even slots are unmapped and act as guard */
-		if (IS_ENABLED(CONFIG_DEBUG_HIGHMEM) && !(i & 0x01)) {
+		if (IS_ENABLED(CONFIG_DEBUG_KMAP_LOCAL) && !(i & 0x01)) {
 			WARN_ON_ONCE(!pte_none(pteval));
 			continue;
 		}
@@ -654,7 +654,7 @@ void __kmap_local_sched_in(void)
 		int idx;
 
 		/* With debug all even slots are unmapped and act as guard */
-		if (IS_ENABLED(CONFIG_DEBUG_HIGHMEM) && !(i & 0x01)) {
+		if (IS_ENABLED(CONFIG_DEBUG_KMAP_LOCAL) && !(i & 0x01)) {
 			WARN_ON_ONCE(!pte_none(pteval));
 			continue;
 		}
-- 
2.28.0.rc0.12.gb6a658bd00c9