51 lines
2.3 KiB
Diff
51 lines
2.3 KiB
Diff
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Date: Mon, 12 Dec 2016 16:14:18 +0100
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Subject: [PATCH] workqueue: use rcu_readlock() in put_pwq_unlocked()
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.8/older/patches-4.8.14-rt9.tar.xz
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The RCU sched protection was changed to RCU only and so all IRQ-off and
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preempt-off disabled region were changed to the relevant rcu-read-lock
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primitives. One was missed and triggered:
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|[ BUG: bad unlock balance detected! ]
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|4.4.30-rt41 #51 Tainted: G W
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|btattach/345 is trying to release lock (
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|Unable to handle kernel paging request at virtual address 6b6b6bbb
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|Backtrace:
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|[<c016b5a0>] (lock_release) from [<c0804844>] (rt_spin_unlock+0x20/0x30)
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|[<c0804824>] (rt_spin_unlock) from [<c0138954>] (put_pwq_unlocked+0xa4/0x118)
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|[<c01388b0>] (put_pwq_unlocked) from [<c0138b2c>] (destroy_workqueue+0x164/0x1b0)
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|[<c01389c8>] (destroy_workqueue) from [<c078e1ac>] (hci_unregister_dev+0x120/0x21c)
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|[<c078e08c>] (hci_unregister_dev) from [<c054f658>] (hci_uart_tty_close+0x90/0xbc)
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|[<c054f5c8>] (hci_uart_tty_close) from [<c03a2be8>] (tty_ldisc_close+0x50/0x58)
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|[<c03a2b98>] (tty_ldisc_close) from [<c03a2cb4>] (tty_ldisc_kill+0x18/0x78)
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|[<c03a2c9c>] (tty_ldisc_kill) from [<c03a3528>] (tty_ldisc_release+0x100/0x134)
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|[<c03a3428>] (tty_ldisc_release) from [<c039cd68>] (tty_release+0x3bc/0x460)
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|[<c039c9ac>] (tty_release) from [<c020cc08>] (__fput+0xe0/0x1b4)
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|[<c020cb28>] (__fput) from [<c020cd3c>] (____fput+0x10/0x14)
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|[<c020cd2c>] (____fput) from [<c013e0d4>] (task_work_run+0xa4/0xb8)
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|[<c013e030>] (task_work_run) from [<c0121754>] (do_exit+0x40c/0x8b0)
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|[<c0121348>] (do_exit) from [<c0122ff8>] (do_group_exit+0x54/0xc4)
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Cc: stable-rt@vger.kernel.org
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Reported-by: John Keeping <john@metanate.com>
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Tested-by: John Keeping <john@metanate.com>
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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kernel/workqueue.c | 2 ++
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1 file changed, 2 insertions(+)
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--- a/kernel/workqueue.c
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+++ b/kernel/workqueue.c
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@@ -1104,9 +1104,11 @@ static void put_pwq_unlocked(struct pool
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* As both pwqs and pools are RCU protected, the
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* following lock operations are safe.
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*/
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+ rcu_read_lock();
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local_spin_lock_irq(pendingb_lock, &pwq->pool->lock);
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put_pwq(pwq);
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local_spin_unlock_irq(pendingb_lock, &pwq->pool->lock);
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+ rcu_read_unlock();
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}
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}
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