[PATCH 1/3] mm/memcontrol: fix reclaim_options leak in try_charge_memcg()

[Bing Jiao]

In try_charge_memcg(), the 'reclaim_options' variable is initialized
once at the start of the function. However, the function contains a
retry loop. If reclaim_options were modified during an iteration
(e.g., by encountering a memsw limit), the modified state would
persist into subsequent retries.

This could lead to incorrect reclaim behavior, such as anon pages
cannot be reclaimed if memsw has quotas after retries.

Fix by moving the initialization of 'reclaim_options' inside the
retry loop, ensuring a clean state for every reclaim attempt.

Fixes: 73b73bac90d9 ("mm: vmpressure: don't count proactive reclaim in vmpressure")
Signed-off-by: Bing Jiao <bingjiao@xxxxxxxxxx>
---
 mm/memcontrol.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index a47fb68dd65f..303ac622d22d 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2558,7 +2558,7 @@ static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask,
 	struct page_counter *counter;
 	unsigned long nr_reclaimed;
 	bool passed_oom = false;
-	unsigned int reclaim_options = MEMCG_RECLAIM_MAY_SWAP;
+	unsigned int reclaim_options;
 	bool drained = false;
 	bool raised_max_event = false;
 	unsigned long pflags;
@@ -2572,6 +2572,7 @@ static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask,
 		/* Avoid the refill and flush of the older stock */
 		batch = nr_pages;

+	reclaim_options = MEMCG_RECLAIM_MAY_SWAP;
 	if (!do_memsw_account() ||
 	    page_counter_try_charge(&memcg->memsw, batch, &counter)) {
 		if (page_counter_try_charge(&memcg->memory, batch, &counter))
--
2.53.0.851.ga537e3e6e9-goog