34 lines
1.2 KiB
Diff
34 lines
1.2 KiB
Diff
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Date: Thu, 16 Nov 2017 16:48:48 +0100
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Subject: [PATCH] locking/rtmutex: re-init the wait_lock in
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rt_mutex_init_proxy_locked()
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.1-rt3.tar.xz
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We could provide a key-class for the lockdep (and fixup all callers) or
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move the init to all callers (like it was) in order to avoid lockdep
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seeing a double-lock of the wait_lock.
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Reported-by: Fernando Lopez-Lezcano <nando@ccrma.Stanford.EDU>
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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kernel/locking/rtmutex.c | 8 ++++++++
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1 file changed, 8 insertions(+)
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--- a/kernel/locking/rtmutex.c
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+++ b/kernel/locking/rtmutex.c
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@@ -2281,6 +2281,14 @@ void rt_mutex_init_proxy_locked(struct r
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struct task_struct *proxy_owner)
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{
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__rt_mutex_init(lock, NULL, NULL);
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+#ifdef CONFIG_DEBUG_SPINLOCK
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+ /*
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+ * get another key class for the wait_lock. LOCK_PI and UNLOCK_PI is
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+ * holding the ->wait_lock of the proxy_lock while unlocking a sleeping
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+ * lock.
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+ */
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+ raw_spin_lock_init(&lock->wait_lock);
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+#endif
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debug_rt_mutex_proxy_lock(lock, proxy_owner);
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rt_mutex_set_owner(lock, proxy_owner);
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}
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