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Groups > linux.kernel > #1295442

[patch 5/5] futex: Cleanup the goto confusion in requeue_pi()

From Thomas Gleixner <tglx@linutronix.de>
Newsgroups linux.kernel
Subject [patch 5/5] futex: Cleanup the goto confusion in requeue_pi()
Date 2015-12-19 21:10 +0100
Message-ID <qHvZf-7LF-9@gated-at.bofh.it> (permalink)
References <qHvZf-7LF-5@gated-at.bofh.it>
Organization linux.* mail to news gateway

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out_unlock: does not only drop the locks, it also drops the refcount
on the pi_state. Really intuitive.

Move the label after the put_pi_state() call and use 'break' in the
error handling path of the requeue loop.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/futex.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -1842,20 +1842,21 @@ static int futex_requeue(u32 __user *uad
 				 */
 				this->pi_state = NULL;
 				put_pi_state(pi_state);
-				goto out_unlock;
+				break;
 			}
 		}
 		requeue_futex(this, hb1, hb2, &key2);
 		drop_count++;
 	}
 
-out_unlock:
 	/*
 	 * We took an extra initial reference to the pi_state either
 	 * in futex_proxy_trylock_atomic() or in lookup_pi_state(). We
 	 * need to drop it here again.
 	 */
 	put_pi_state(pi_state);
+
+out_unlock:
 	double_unlock_hb(hb1, hb2);
 	wake_up_q(&wake_q);
 	hb_waiters_dec(hb2);


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Thread

[patch 0/5] futex: Plug a pi_state leak and clarify the refcounting Thomas Gleixner <tglx@linutronix.de> - 2015-12-19 21:10 +0100
  [patch 5/5] futex: Cleanup the goto confusion in requeue_pi() Thomas Gleixner <tglx@linutronix.de> - 2015-12-19 21:10 +0100
    Re: [patch 5/5] futex: Cleanup the goto confusion in requeue_pi() Darren Hart <dvhart@infradead.org> - 2015-12-20 06:20 +0100
      Re: [patch 5/5] futex: Cleanup the goto confusion in requeue_pi() Mike Galbraith <umgwanakikbuti@gmail.com> - 2015-12-20 06:50 +0100
        Re: [patch 5/5] futex: Cleanup the goto confusion in requeue_pi() Darren Hart <dvhart@infradead.org> - 2015-12-20 08:40 +0100
      Re: [patch 5/5] futex: Cleanup the goto confusion in requeue_pi() Darren Hart <dvhart@infradead.org> - 2015-12-20 06:50 +0100
    [tip:locking/core] futex:   Cleanup the goto confusion in requeue_pi() tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2015-12-20 14:30 +0100
  [patch 3/5] futex: Document pi_state refcounting in requeue code Thomas Gleixner <tglx@linutronix.de> - 2015-12-19 21:10 +0100
    Re: [patch 3/5] futex: Document pi_state refcounting in requeue code Darren Hart <dvhart@infradead.org> - 2015-12-20 08:50 +0100
    [tip:locking/core] futex:   Document pi_state refcounting in requeue code tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2015-12-20 14:30 +0100
  [patch 1/5] futex: Drop refcount if requeue_pi() acquired the rtmutex Thomas Gleixner <tglx@linutronix.de> - 2015-12-19 21:10 +0100
    [tip:locking/core] futex: Drop refcount if requeue_pi()   acquired the rtmutex tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2015-12-20 14:30 +0100
  [patch 2/5] futex: Rename free_pi_state() to put_pi_state() Thomas Gleixner <tglx@linutronix.de> - 2015-12-19 21:10 +0100
    [tip:locking/core] futex: Rename free_pi_state() to put_pi_state(  ) tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2015-12-20 14:30 +0100
  [patch 4/5] futex: Remove pointless put_pi_state calls in requeue() Thomas Gleixner <tglx@linutronix.de> - 2015-12-19 21:20 +0100
    [tip:locking/core] futex:   Remove pointless put_pi_state calls in requeue() tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2015-12-20 14:30 +0100

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