[PATCH] khugepaged: avoid usage of uninitialized variable 'isolated'

From: Kirill A. Shutemov
Date: Thu Sep 17 2015 - 09:35:57 EST


In file included from include/trace/events/huge_memory.h:7:0,
from mm/huge_memory.c:62:
include/linux/tracepoint.h:141:5: warning: âisolatedâ may be used uninitialized in this function [-Wmaybe-uninitialized]
((void(*)(proto))(it_func))(args); \
^
mm/huge_memory.c:2327:6: note: âisolatedâ was declared here
int isolated, result = 0;

We make use of isolated in error path before it get initialized.

The patch also makes trivial cleanup of exit path of the function.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
mm/huge_memory.c | 7 +------
1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 5ad5c443cc94..857f92e85c38 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2656,8 +2656,6 @@ static void __collapse_huge_page_swapin(struct mm_struct *mm,
trace_mm_collapse_huge_page_swapin(mm, swapped_in, 1);
}

-
-
static void collapse_huge_page(struct mm_struct *mm,
unsigned long address,
struct page **hpage,
@@ -2669,7 +2667,7 @@ static void collapse_huge_page(struct mm_struct *mm,
pgtable_t pgtable;
struct page *new_page;
spinlock_t *pmd_ptl, *pte_ptl;
- int isolated, result = 0;
+ int isolated = 0, result = 0;
unsigned long hstart, hend;
struct mem_cgroup *memcg;
unsigned long mmun_start; /* For mmu_notifiers */
@@ -2805,9 +2803,6 @@ static void collapse_huge_page(struct mm_struct *mm,
result = SCAN_SUCCEED;
out_up_write:
up_write(&mm->mmap_sem);
- trace_mm_collapse_huge_page(mm, isolated, result);
- return;
-
out_nolock:
trace_mm_collapse_huge_page(mm, isolated, result);
return;
--
Kirill A. Shutemov
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