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From: Peter Zijlstra <peterz@infradead.org>
To: tglx@linutronix.de
Cc: mingo@kernel.org, juri.lelli@arm.com, rostedt@goodmis.org,
	xlpang@redhat.com, bigeasy@linutronix.de,
	linux-kernel@vger.kernel.org, mathieu.desnoyers@efficios.com,
	jdesfossez@efficios.com, bristot@redhat.com,
	dvhart@infradead.org, peterz@infradead.org,
	Darren Hart <dvhart@linux.intel.com>
Subject: [PATCH -v5 02/14] futex: Add missing error handling to FUTEX_REQUEUE_PI
Date: Sat, 04 Mar 2017 10:27:19 +0100
Message-ID: <20170304093558.867401760@infradead.org> (raw)
In-Reply-To: <20170304092717.762954142@infradead.org>

[-- Attachment #0: peter_zijlstra-futex-fix_missing_error_handling.patch --]
[-- Type: text/plain, Size: 787 bytes --]

Thomas spotted that fixup_pi_state_owner() can return errors and we
fail to unlock the rt_mutex in that case.

Reviewed-by: Darren Hart <dvhart@linux.intel.com>
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 kernel/futex.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2896,6 +2896,8 @@ static int futex_wait_requeue_pi(u32 __u
 		if (q.pi_state && (q.pi_state->owner != current)) {
 			spin_lock(q.lock_ptr);
 			ret = fixup_pi_state_owner(uaddr2, &q, current);
+			if (ret && rt_mutex_owner(&q.pi_state->pi_mutex) == current)
+				rt_mutex_unlock(&q.pi_state->pi_mutex);
 			/*
 			 * Drop the reference to the pi state which
 			 * the requeue_pi() code acquired for us.

  parent reply index

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-04  9:27 [PATCH -v5 00/14] the saga of FUTEX_UNLOCK_PI wobbles continues Peter Zijlstra
2017-03-04  9:27 ` [PATCH -v5 01/14] futex: Fix potential use-after-free in FUTEX_REQUEUE_PI Peter Zijlstra
2017-03-14 20:48   ` [tip:locking/urgent] " tip-bot for Peter Zijlstra
2017-03-04  9:27 ` Peter Zijlstra [this message]
2017-03-14 20:49   ` [tip:locking/urgent] futex: Add missing error handling to FUTEX_REQUEUE_PI tip-bot for Peter Zijlstra
2017-03-04  9:27 ` [PATCH -v5 03/14] futex: Cleanup variable names for futex_top_waiter() Peter Zijlstra
2017-03-04  9:27 ` [PATCH -v5 04/14] futex: Use smp_store_release() in mark_wake_futex() Peter Zijlstra
2017-03-04  9:27 ` [PATCH -v5 05/14] futex: Remove rt_mutex_deadlock_account_*() Peter Zijlstra
2017-03-04  9:27 ` [PATCH -v5 06/14] futex,rt_mutex: Provide futex specific rt_mutex API Peter Zijlstra
2017-03-04  9:27 ` [PATCH -v5 07/14] futex: Change locking rules Peter Zijlstra
2017-03-07 13:22   ` Thomas Gleixner
2017-03-07 16:47     ` Sebastian Andrzej Siewior
2017-03-07 18:01       ` Peter Zijlstra
2017-03-04  9:27 ` [PATCH -v5 08/14] futex: Cleanup refcounting Peter Zijlstra
2017-03-04  9:27 ` [PATCH -v5 09/14] futex: Rework inconsistent rt_mutex/futex_q state Peter Zijlstra
2017-03-07 13:26   ` Thomas Gleixner
2017-03-04  9:27 ` [PATCH -v5 10/14] futex: Pull rt_mutex_futex_unlock() out from under hb->lock Peter Zijlstra
2017-03-07 14:08   ` Thomas Gleixner
2017-03-07 18:01     ` Peter Zijlstra
2017-03-04  9:27 ` [PATCH -v5 11/14] futex,rt_mutex: Introduce rt_mutex_init_waiter() Peter Zijlstra
2017-03-04  9:27 ` [PATCH -v5 12/14] futex,rt_mutex: Restructure rt_mutex_finish_proxy_lock() Peter Zijlstra
2017-03-07 14:18   ` Thomas Gleixner
2017-03-07 17:57     ` Peter Zijlstra
2017-03-07 17:59       ` Thomas Gleixner
2017-03-08 15:29   ` [PATCH] futex: move debug_rt_mutex_free_waiter() further down Sebastian Andrzej Siewior
2017-03-08 15:37     ` Sebastian Andrzej Siewior
2017-03-08 16:21       ` Steven Rostedt
2017-03-08 16:20     ` Steven Rostedt
2017-03-13  9:16     ` Peter Zijlstra
2017-03-04  9:27 ` [PATCH -v5 13/14] futex: Rework futex_lock_pi() to use rt_mutex_*_proxy_lock() Peter Zijlstra
2017-03-04  9:27 ` [PATCH -v5 14/14] futex: futex_unlock_pi() determinism Peter Zijlstra
2017-03-07 14:31   ` Thomas Gleixner
2017-03-07 17:59     ` Peter Zijlstra
2017-03-13  9:25     ` Peter Zijlstra
2017-03-13 14:25       ` Thomas Gleixner
2017-03-13 15:11         ` Peter Zijlstra

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