[PATCH -next] locking/percpu-rwsem: fix a task_struct refcount

From: Qian Cai
Date: Thu Mar 26 2020 - 23:12:14 EST


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@xxxxxx>
---
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)