57 lines
2 KiB
Diff
57 lines
2 KiB
Diff
From: Thomas Gleixner <tglx@linutronix.de>
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Date: Fri, 8 Sep 2023 18:22:53 +0200
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Subject: [PATCH 6/7] locking/rtmutex: Add a lockdep assert to catch potential
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nested blocking
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz
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There used to be a BUG_ON(current->pi_blocked_on) in the lock acquisition
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functions, but that vanished in one of the rtmutex overhauls.
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Bring it back in form of a lockdep assert to catch code paths which take
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rtmutex based locks with current::pi_blocked_on != NULL.
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Reported-by: Crystal Wood <swood@redhat.com>
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Signed-off-by: "Peter Zijlstra (Intel)" <peterz@infradead.org>
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
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Link: https://lkml.kernel.org/r/20230908162254.999499-7-bigeasy@linutronix.de
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---
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kernel/locking/rtmutex.c | 2 ++
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kernel/locking/rwbase_rt.c | 2 ++
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kernel/locking/spinlock_rt.c | 2 ++
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3 files changed, 6 insertions(+)
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--- a/kernel/locking/rtmutex.c
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+++ b/kernel/locking/rtmutex.c
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@@ -1784,6 +1784,8 @@ static int __sched rt_mutex_slowlock(str
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static __always_inline int __rt_mutex_lock(struct rt_mutex_base *lock,
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unsigned int state)
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{
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+ lockdep_assert(!current->pi_blocked_on);
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+
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if (likely(rt_mutex_try_acquire(lock)))
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return 0;
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--- a/kernel/locking/rwbase_rt.c
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+++ b/kernel/locking/rwbase_rt.c
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@@ -133,6 +133,8 @@ static int __sched __rwbase_read_lock(st
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static __always_inline int rwbase_read_lock(struct rwbase_rt *rwb,
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unsigned int state)
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{
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+ lockdep_assert(!current->pi_blocked_on);
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+
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if (rwbase_read_trylock(rwb))
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return 0;
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--- a/kernel/locking/spinlock_rt.c
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+++ b/kernel/locking/spinlock_rt.c
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@@ -37,6 +37,8 @@
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static __always_inline void rtlock_lock(struct rt_mutex_base *rtm)
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{
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+ lockdep_assert(!current->pi_blocked_on);
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+
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if (unlikely(!rt_mutex_cmpxchg_acquire(rtm, NULL, current)))
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rtlock_slowlock(rtm);
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}
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