From 73d7a69de212aebb59f4ff23aae0422e86c488fe Mon Sep 17 00:00:00 2001 From: SeongJae Park Date: Fri, 28 Feb 2025 09:44:50 -0800 Subject: [PATCH] mm/damon/core: initialize damos->walk_completed in damon_new_scheme() The function for allocating and initialize a 'struct damos' object, damon_new_scheme(), is not initializing damos->walk_completed field. Only damos_walk_complete() is setting the field. Hence the field will be eventually set and used correctly from second damos_walk() call for the scheme. But the first damos_walk() could mistakenly not walk on the regions. Actually, a common usage of DAMOS for taking an access pattern snapshot is installing a monitoring-purpose DAMOS scheme, doing damos_walk() to retrieve the snapshot, and then removing the scheme. DAMON user-space tool (damo) also gets runtime snapshot in the way. Hence the problem can continuously happen in such use cases. Initialize it properly in the allocation function. Link: https://lkml.kernel.org/r/20250228174450.41472-1-sj@kernel.org Fixes: bf0eaba0ff9c ("mm/damon/core: implement damos_walk()") Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton --- mm/damon/core.c | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/damon/core.c b/mm/damon/core.c index de4396519b83..384935ef4e65 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -373,6 +373,7 @@ struct damos *damon_new_scheme(struct damos_access_pattern *pattern, * or damon_attrs are updated. */ scheme->next_apply_sis = 0; + scheme->walk_completed = false; INIT_LIST_HEAD(&scheme->filters); scheme->stat = (struct damos_stat){}; INIT_LIST_HEAD(&scheme->list);