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From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org,
	linux-rt-users <linux-rt-users@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Carsten Emde <C.Emde@osadl.org>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	John Kacur <jkacur@redhat.com>,
	Paul Gortmaker <paul.gortmaker@windriver.com>,
	stable-rt@vger.kernel.org, John Keeping <john@metanate.com>
Subject: [PATCH RT 4/5] workqueue: use rcu_readlock() in put_pwq_unlocked()
Date: Thu, 09 Feb 2017 10:21:19 -0500	[thread overview]
Message-ID: <20170209152229.750478840@goodmis.org> (raw)
In-Reply-To: 20170209152115.146963512@goodmis.org

[-- Attachment #1: 0004-workqueue-use-rcu_readlock-in-put_pwq_unlocked.patch --]
[-- Type: text/plain, Size: 2427 bytes --]

4.4.47-rt59-rc1 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

The RCU sched protection was changed to RCU only and so all IRQ-off and
preempt-off disabled region were changed to the relevant rcu-read-lock
primitives. One was missed and triggered:
|[ BUG: bad unlock balance detected! ]
|4.4.30-rt41 #51 Tainted: G        W
|btattach/345 is trying to release lock (
|Unable to handle kernel paging request at virtual address 6b6b6bbb
|Backtrace:
|[<c016b5a0>] (lock_release) from [<c0804844>] (rt_spin_unlock+0x20/0x30)
|[<c0804824>] (rt_spin_unlock) from [<c0138954>] (put_pwq_unlocked+0xa4/0x118)
|[<c01388b0>] (put_pwq_unlocked) from [<c0138b2c>] (destroy_workqueue+0x164/0x1b0)
|[<c01389c8>] (destroy_workqueue) from [<c078e1ac>] (hci_unregister_dev+0x120/0x21c)
|[<c078e08c>] (hci_unregister_dev) from [<c054f658>] (hci_uart_tty_close+0x90/0xbc)
|[<c054f5c8>] (hci_uart_tty_close) from [<c03a2be8>] (tty_ldisc_close+0x50/0x58)
|[<c03a2b98>] (tty_ldisc_close) from [<c03a2cb4>] (tty_ldisc_kill+0x18/0x78)
|[<c03a2c9c>] (tty_ldisc_kill) from [<c03a3528>] (tty_ldisc_release+0x100/0x134)
|[<c03a3428>] (tty_ldisc_release) from [<c039cd68>] (tty_release+0x3bc/0x460)
|[<c039c9ac>] (tty_release) from [<c020cc08>] (__fput+0xe0/0x1b4)
|[<c020cb28>] (__fput) from [<c020cd3c>] (____fput+0x10/0x14)
|[<c020cd2c>] (____fput) from [<c013e0d4>] (task_work_run+0xa4/0xb8)
|[<c013e030>] (task_work_run) from [<c0121754>] (do_exit+0x40c/0x8b0)
|[<c0121348>] (do_exit) from [<c0122ff8>] (do_group_exit+0x54/0xc4)

Cc: stable-rt@vger.kernel.org
Reported-by: John Keeping <john@metanate.com>
Tested-by: John Keeping <john@metanate.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/workqueue.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 965d5f65e847..d5b0f4fc0eb0 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1135,9 +1135,11 @@ static void put_pwq_unlocked(struct pool_workqueue *pwq)
 		 * As both pwqs and pools are RCU protected, the
 		 * following lock operations are safe.
 		 */
+		rcu_read_lock();
 		local_spin_lock_irq(pendingb_lock, &pwq->pool->lock);
 		put_pwq(pwq);
 		local_spin_unlock_irq(pendingb_lock, &pwq->pool->lock);
+		rcu_read_unlock();
 	}
 }
 
-- 
2.10.2

  parent reply	other threads:[~2017-02-09 15:21 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-09 15:21 [PATCH RT 0/5] Linux 4.4.47-rt59-rc1 Steven Rostedt
2017-02-09 15:21 ` [PATCH RT 1/5] arm: kprobe: replace patch_lock to raw lock Steven Rostedt
2017-02-09 15:21 ` [PATCH RT 2/5] net: free the sbs in skbufhead Steven Rostedt
2017-02-09 15:21 ` [PATCH RT 3/5] net: Have __napi_schedule_irqoff() disable interrupts on RT Steven Rostedt
2017-02-09 15:21 ` Steven Rostedt [this message]
2017-02-09 15:21 ` [PATCH RT 5/5] Linux 4.4.47-rt59-rc1 Steven Rostedt
  -- strict thread matches above, loose matches on Subject: below --
2017-02-09 15:32 [PATCH RT 0/5] Linux 4.1.38-rt45-rc1 Steven Rostedt
2017-02-09 15:32 ` [PATCH RT 4/5] workqueue: use rcu_readlock() in put_pwq_unlocked() Steven Rostedt

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