mm: avoid uninitialized variable in tracepoint

A newly added tracepoint in the hugepage code uses a variable in the
error handling that is not initialized at that point:

include/trace/events/huge_memory.h:81:230: error: 'isolated' may be used uninitialized in this function [-Werror=maybe-uninitialized]

The result is relatively harmless, as the trace data will in rare
cases contain incorrect data.

This works around the problem by adding an explicit initialization.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 7d2eba0557c1 ("mm: add tracepoint for scanning pages")
Reviewed-by: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 50342eff796043e8e6c3daaac27c7c3779614a20..b1cf73bc3b12969f00740031ac60f28840ac212d 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2320,7 +2320,7 @@ 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 */