From e68d343d2720779362cb7160cb7f4bd24979b2b4 Mon Sep 17 00:00:00 2001 From: Waiman Long Date: Fri, 25 Aug 2023 12:49:47 -0400 Subject: mm/kmemleak: move up cond_resched() call in page scanning loop Commit bde5f6bc68db ("kmemleak: add scheduling point to kmemleak_scan()") added a cond_resched() call to the struct page scanning loop to prevent soft lockup from happening. However, soft lockup can still happen in that loop in some corner cases when the pages that satisfy the "!(pfn & 63)" check are skipped for some reasons. Fix this corner case by moving up the cond_resched() check so that it will be called every 64 pages unconditionally. Link: https://lkml.kernel.org/r/20230825164947.1317981-1-longman@redhat.com Fixes: bde5f6bc68db ("kmemleak: add scheduling point to kmemleak_scan()") Signed-off-by: Waiman Long Cc: Catalin Marinas Cc: Yisheng Xie Signed-off-by: Andrew Morton --- mm/kmemleak.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'mm') diff --git a/mm/kmemleak.c b/mm/kmemleak.c index 2918150e31bd..54c2c90d3abc 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -1584,6 +1584,9 @@ static void kmemleak_scan(void) for (pfn = start_pfn; pfn < end_pfn; pfn++) { struct page *page = pfn_to_online_page(pfn); + if (!(pfn & 63)) + cond_resched(); + if (!page) continue; @@ -1594,8 +1597,6 @@ static void kmemleak_scan(void) if (page_count(page) == 0) continue; scan_block(page, page + 1, NULL); - if (!(pfn & 63)) - cond_resched(); } } put_online_mems(); -- cgit v1.2.3