From: Jackie Liu <liuyun01@kylinos.cn>
Date: Tue, 31 Mar 2026 10:15:53 +0000 (+0800)
Subject: mm/damon/stat: fix memory leak on damon_start() failure in damon_stat_start()
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=e04ed278d25bf15769800bf6e35c6737f137186f;p=thirdparty%2Fkernel%2Flinux.git

mm/damon/stat: fix memory leak on damon_start() failure in damon_stat_start()

Destroy the DAMON context and reset the global pointer when damon_start()
fails.  Otherwise, the context allocated by damon_stat_build_ctx() is
leaked, and the stale damon_stat_context pointer will be overwritten on
the next enable attempt, making the old allocation permanently
unreachable.

Link: https://lore.kernel.org/20260331101553.88422-1-liu.yun@linux.dev
Fixes: 369c415e6073 ("mm/damon: introduce DAMON_STAT module")
Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> # 6.17.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/damon/stat.c b/mm/damon/stat.c
index cf2c5a541eee..5a742fc157e4 100644
--- a/mm/damon/stat.c
+++ b/mm/damon/stat.c
@@ -249,8 +249,11 @@ static int damon_stat_start(void)
 	if (!damon_stat_context)
 		return -ENOMEM;
 	err = damon_start(&damon_stat_context, 1, true);
-	if (err)
+	if (err) {
+		damon_destroy_ctx(damon_stat_context);
+		damon_stat_context = NULL;
 		return err;
+	}
 
 	damon_stat_last_refresh_jiffies = jiffies;
 	call_control.data = damon_stat_context;