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>, Julia Cartwright <julia@ni.com>, Daniel Wagner <wagi@monom.org>, Tom Zanussi <zanussi@kernel.org> Subject: [PATCH RT 26/30] locking: Make spinlock_t and rwlock_t a RCU section on RT Date: Thu, 23 Jan 2020 15:39:56 -0500 [thread overview] Message-ID: <20200123203946.055628942@goodmis.org> (raw) In-Reply-To: <20200123203930.646725253@goodmis.org> 4.19.94-rt39-rc2 stable review patch. If anyone has any objections, please let me know. ------------------ From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> [ Upstream commit 84440022a0e1c8c936d61f8f97593674a295d409 ] On !RT a locked spinlock_t and rwlock_t disables preemption which implies a RCU read section. There is code that relies on that behaviour. Add an explicit RCU read section on RT while a sleeping lock (a lock which would disables preemption on !RT) acquired. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> --- kernel/locking/rtmutex.c | 6 ++++++ kernel/locking/rwlock-rt.c | 6 ++++++ 2 files changed, 12 insertions(+) diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c index 63b3d6f306fa..c7d3ae01b4e5 100644 --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -1142,6 +1142,7 @@ void __sched rt_spin_lock_slowunlock(struct rt_mutex *lock) void __lockfunc rt_spin_lock(spinlock_t *lock) { sleeping_lock_inc(); + rcu_read_lock(); migrate_disable(); spin_acquire(&lock->dep_map, 0, 0, _RET_IP_); rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock); @@ -1157,6 +1158,7 @@ void __lockfunc __rt_spin_lock(struct rt_mutex *lock) void __lockfunc rt_spin_lock_nested(spinlock_t *lock, int subclass) { sleeping_lock_inc(); + rcu_read_lock(); migrate_disable(); spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_); rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock); @@ -1170,6 +1172,7 @@ void __lockfunc rt_spin_unlock(spinlock_t *lock) spin_release(&lock->dep_map, 1, _RET_IP_); rt_spin_lock_fastunlock(&lock->lock, rt_spin_lock_slowunlock); migrate_enable(); + rcu_read_unlock(); sleeping_lock_dec(); } EXPORT_SYMBOL(rt_spin_unlock); @@ -1201,6 +1204,7 @@ int __lockfunc rt_spin_trylock(spinlock_t *lock) ret = __rt_mutex_trylock(&lock->lock); if (ret) { spin_acquire(&lock->dep_map, 0, 1, _RET_IP_); + rcu_read_lock(); } else { migrate_enable(); sleeping_lock_dec(); @@ -1217,6 +1221,7 @@ int __lockfunc rt_spin_trylock_bh(spinlock_t *lock) ret = __rt_mutex_trylock(&lock->lock); if (ret) { sleeping_lock_inc(); + rcu_read_lock(); migrate_disable(); spin_acquire(&lock->dep_map, 0, 1, _RET_IP_); } else @@ -1233,6 +1238,7 @@ int __lockfunc rt_spin_trylock_irqsave(spinlock_t *lock, unsigned long *flags) ret = __rt_mutex_trylock(&lock->lock); if (ret) { sleeping_lock_inc(); + rcu_read_lock(); migrate_disable(); spin_acquire(&lock->dep_map, 0, 1, _RET_IP_); } diff --git a/kernel/locking/rwlock-rt.c b/kernel/locking/rwlock-rt.c index c3b91205161c..0ae8c62ea832 100644 --- a/kernel/locking/rwlock-rt.c +++ b/kernel/locking/rwlock-rt.c @@ -310,6 +310,7 @@ int __lockfunc rt_read_trylock(rwlock_t *rwlock) ret = do_read_rt_trylock(rwlock); if (ret) { rwlock_acquire_read(&rwlock->dep_map, 0, 1, _RET_IP_); + rcu_read_lock(); } else { migrate_enable(); sleeping_lock_dec(); @@ -327,6 +328,7 @@ int __lockfunc rt_write_trylock(rwlock_t *rwlock) ret = do_write_rt_trylock(rwlock); if (ret) { rwlock_acquire(&rwlock->dep_map, 0, 1, _RET_IP_); + rcu_read_lock(); } else { migrate_enable(); sleeping_lock_dec(); @@ -338,6 +340,7 @@ EXPORT_SYMBOL(rt_write_trylock); void __lockfunc rt_read_lock(rwlock_t *rwlock) { sleeping_lock_inc(); + rcu_read_lock(); migrate_disable(); rwlock_acquire_read(&rwlock->dep_map, 0, 0, _RET_IP_); do_read_rt_lock(rwlock); @@ -347,6 +350,7 @@ EXPORT_SYMBOL(rt_read_lock); void __lockfunc rt_write_lock(rwlock_t *rwlock) { sleeping_lock_inc(); + rcu_read_lock(); migrate_disable(); rwlock_acquire(&rwlock->dep_map, 0, 0, _RET_IP_); do_write_rt_lock(rwlock); @@ -358,6 +362,7 @@ void __lockfunc rt_read_unlock(rwlock_t *rwlock) rwlock_release(&rwlock->dep_map, 1, _RET_IP_); do_read_rt_unlock(rwlock); migrate_enable(); + rcu_read_unlock(); sleeping_lock_dec(); } EXPORT_SYMBOL(rt_read_unlock); @@ -367,6 +372,7 @@ void __lockfunc rt_write_unlock(rwlock_t *rwlock) rwlock_release(&rwlock->dep_map, 1, _RET_IP_); do_write_rt_unlock(rwlock); migrate_enable(); + rcu_read_unlock(); sleeping_lock_dec(); } EXPORT_SYMBOL(rt_write_unlock); -- 2.24.1
next prev parent reply other threads:[~2020-01-23 20:40 UTC|newest] Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-01-23 20:39 [PATCH RT 00/30] Linux 4.19.94-rt39-rc2 Steven Rostedt 2020-01-23 20:39 ` [PATCH RT 01/30] i2c: exynos5: Remove IRQF_ONESHOT Steven Rostedt 2020-01-23 20:39 ` [PATCH RT 02/30] i2c: hix5hd2: " Steven Rostedt 2020-01-23 20:39 ` [PATCH RT 03/30] sched/deadline: Ensure inactive_timer runs in hardirq context Steven Rostedt 2020-01-23 20:39 ` [PATCH RT 04/30] thermal/x86_pkg_temp: make pkg_temp_lock a raw spinlock Steven Rostedt 2020-01-23 20:39 ` [PATCH RT 05/30] dma-buf: Use seqlock_t instread disabling preemption Steven Rostedt 2020-01-23 20:39 ` [PATCH RT 06/30] KVM: arm/arm64: Let the timer expire in hardirq context on RT Steven Rostedt 2020-01-23 20:39 ` [PATCH RT 07/30] x86: preempt: Check preemption level before looking at lazy-preempt Steven Rostedt 2020-01-23 20:39 ` [PATCH RT 08/30] hrtimer: Use READ_ONCE to access timer->base in hrimer_grab_expiry_lock() Steven Rostedt 2020-01-23 20:39 ` [PATCH RT 09/30] hrtimer: Dont grab the expiry lock for non-soft hrtimer Steven Rostedt 2020-01-23 20:39 ` [PATCH RT 10/30] hrtimer: Prevent using hrtimer_grab_expiry_lock() on migration_base Steven Rostedt 2020-04-27 13:10 ` Rasmus Villemoes 2020-04-27 19:06 ` Steven Rostedt 2020-04-27 19:26 ` Tom Zanussi 2020-04-28 6:51 ` Rasmus Villemoes 2020-04-28 7:03 ` Rasmus Villemoes 2020-04-28 12:59 ` Tom Zanussi 2020-04-28 13:07 ` Rasmus Villemoes 2020-04-28 13:43 ` Tom Zanussi 2020-01-23 20:39 ` [PATCH RT 11/30] hrtimer: Add a missing bracket and hide `migration_base on !SMP Steven Rostedt 2020-01-23 20:39 ` [PATCH RT 12/30] posix-timers: Unlock expiry lock in the early return Steven Rostedt 2020-01-23 20:39 ` [PATCH RT 14/30] sched: __set_cpus_allowed_ptr: Check cpus_mask, not cpus_ptr Steven Rostedt 2020-01-23 20:39 ` [PATCH RT 15/30] sched: Remove dead __migrate_disabled() check Steven Rostedt 2020-01-23 20:39 ` [PATCH RT 16/30] sched: migrate disable: Protect cpus_ptr with lock Steven Rostedt 2020-01-23 20:39 ` [PATCH RT 17/30] lib/smp_processor_id: Dont use cpumask_equal() Steven Rostedt 2020-01-23 20:39 ` [PATCH RT 18/30] futex: Make the futex_hash_bucket spinlock_t again and bring back its old state Steven Rostedt 2020-01-23 20:39 ` [PATCH RT 19/30] locking/rtmutex: Clean ->pi_blocked_on in the error case Steven Rostedt 2020-01-23 20:39 ` [PATCH RT 20/30] lib/ubsan: Dont seralize UBSAN report Steven Rostedt 2020-01-23 20:39 ` [PATCH RT 21/30] kmemleak: Change the lock of kmemleak_object to raw_spinlock_t Steven Rostedt 2020-01-23 20:39 ` [PATCH RT 22/30] sched: migrate_enable: Use select_fallback_rq() Steven Rostedt 2020-01-23 20:39 ` [PATCH RT 23/30] sched: Lazy migrate_disable processing Steven Rostedt 2020-01-23 20:39 ` [PATCH RT 24/30] sched: migrate_enable: Use stop_one_cpu_nowait() Steven Rostedt 2020-01-23 20:39 ` [PATCH RT 25/30] Revert "ARM: Initialize split page table locks for vector page" Steven Rostedt 2020-01-23 20:39 ` Steven Rostedt [this message] 2020-01-23 20:39 ` [PATCH RT 27/30] sched/core: migrate_enable() must access takedown_cpu_task on !HOTPLUG_CPU Steven Rostedt 2020-01-23 20:39 ` [PATCH RT 28/30] lib/smp_processor_id: Adjust check_preemption_disabled() Steven Rostedt 2020-01-23 20:39 ` [PATCH RT 29/30] sched: migrate_enable: Busy loop until the migration request is completed Steven Rostedt 2020-01-23 20:40 ` [PATCH RT 30/30] Linux 4.19.94-rt39-rc2 Steven Rostedt
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