From: Waiman Long <Waiman.Long@hpe.com>
To: Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@redhat.com>
Cc: linux-kernel@vger.kernel.org, Davidlohr Bueso <dave@stgolabs.net>,
Jason Low <jason.low2@hp.com>, Dave Chinner <david@fromorbit.com>,
Peter Hurley <peter@hurleysoftware.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Scott J Norton <scott.norton@hpe.com>,
Douglas Hatch <doug.hatch@hpe.com>,
Waiman Long <Waiman.Long@hpe.com>
Subject: [PATCH resend v4 3/5] locking/rwsem: Don't wake up one's own task
Date: Fri, 20 May 2016 19:16:26 -0400 [thread overview]
Message-ID: <1463786186-1065-1-git-send-email-Waiman.Long@hpe.com> (raw)
As rwsem_down_read_failed() will queue itself and potentially call
__rwsem_do_wake(sem, RWSEM_WAKE_ANY), it is possible that a reader
will try to wake up its own task. This patch adds a check to make
sure that this won't happen.
Signed-off-by: Waiman Long <Waiman.Long@hpe.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
---
kernel/locking/rwsem-xadd.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c
index c278f5a..007814f 100644
--- a/kernel/locking/rwsem-xadd.c
+++ b/kernel/locking/rwsem-xadd.c
@@ -202,7 +202,8 @@ __rwsem_do_wake(struct rw_semaphore *sem, enum rwsem_wake_type wake_type)
*/
smp_mb();
waiter->task = NULL;
- wake_up_process(tsk);
+ if (likely(tsk != current))
+ wake_up_process(tsk);
put_task_struct(tsk);
} while (--loop);
--
1.7.1
reply other threads:[~2016-05-20 23:16 UTC|newest]
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