linux-kernel - [PATCH -next] locking/percpu-rwsem: fix a task

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Message-Id: <20200327031057.10866-1-cai@lca.pw>
Date:   Thu, 26 Mar 2020 23:10:57 -0400
From:   Qian Cai <cai@....pw>
To:     peterz@...radead.org, mingo@...hat.com
Cc:     will@...nel.org, dbueso@...e.de, juri.lelli@...hat.com,
        longman@...hat.com, linux-kernel@...r.kernel.org,
        Qian Cai <cai@....pw>
Subject: [PATCH -next] locking/percpu-rwsem: fix a task_struct refcount

There are some memory leaks due to a missing put_task_struct().

Fixes: 7f26482a872c ("locking/percpu-rwsem: Remove the embedded rwsem")
Signed-off-by: Qian Cai <cai@....pw>
---
 kernel/locking/percpu-rwsem.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/locking/percpu-rwsem.c b/kernel/locking/percpu-rwsem.c
index a008a1ba21a7..6f487e5d923f 100644
--- a/kernel/locking/percpu-rwsem.c
+++ b/kernel/locking/percpu-rwsem.c
@@ -123,8 +123,10 @@ static int percpu_rwsem_wake_function(struct wait_queue_entry *wq_entry,
 	struct percpu_rw_semaphore *sem = key;
 
 	/* concurrent against percpu_down_write(), can get stolen */
-	if (!__percpu_rwsem_trylock(sem, reader))
+	if (!__percpu_rwsem_trylock(sem, reader)) {
+		put_task_struct(p);
 		return 1;
+	}
 
 	list_del_init(&wq_entry->entry);
 	smp_store_release(&wq_entry->private, NULL);
-- 
2.21.0 (Apple Git-122.2)