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Fri, 19 Jun 2026 20:29:39 -0700 (PDT) From: yahia To: sj@kernel.org Cc: akpm@linux-foundation.org, damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, yahia ahmed Subject: [PATCH v3] mm/damon/reclaim: fix potential memory leak Date: Sat, 20 Jun 2026 06:29:31 +0300 Message-ID: <20260620032931.14281-1-yahia.a.abdrabou@gmail.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260620003557.243313-2-yahia.a.abdrabou@gmail.com> References: <20260620003557.243313-2-yahia.a.abdrabou@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: yahia ahmed Fix a potential race condition by locking the ctx then using damon_stop() to eliminate the thread then destroy ctx. Signed-off-by: yahia ahmed v3: - Add a mutex lock to prevent possible race condition - Stop the kdamond thread before destroying ctx v2: - Remove early return - Set ctx to NULL to avoid a use after free - Fix typo --- mm/damon/reclaim.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/mm/damon/reclaim.c b/mm/damon/reclaim.c index 6601b08996c6..ec5558b7da41 100644 --- a/mm/damon/reclaim.c +++ b/mm/damon/reclaim.c @@ -480,6 +480,15 @@ static int __init damon_reclaim_init(void) enabled = false; if (err && ctx) { + /* Hold a lock and stop the thread to prevent a possible race condition */ + mutex_lock(&ctx->kdamond_lock); + + if (ctx->kdamond) { + mutex_unlock(&ctx->kdamond_lock); + damon_stop(ctx); + } else { + mutex_unlock(&ctx->kdamond_lock); + } damon_destroy_ctx(ctx); ctx = NULL; } -- 2.54.0