From: zanussi@kernel.org
To: LKML <linux-kernel@vger.kernel.org>,
linux-rt-users <linux-rt-users@vger.kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Thomas Gleixner <tglx@linutronix.de>,
Carsten Emde <C.Emde@osadl.org>, John Kacur <jkacur@redhat.com>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Daniel Wagner <wagi@monom.org>, Tom Zanussi <zanussi@kernel.org>
Subject: [PATCH RT 15/23] locking: Make spinlock_t and rwlock_t a RCU section on RT
Date: Thu, 27 Feb 2020 08:33:26 -0600 [thread overview]
Message-ID: <186fec3947a0cc8b99cbf8211a91c52140813302.1582814004.git.zanussi@kernel.org> (raw)
In-Reply-To: <cover.1582814004.git.zanussi@kernel.org>
In-Reply-To: <cover.1582814004.git.zanussi@kernel.org>
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
v4.14.170-rt75-rc2 stable review patch.
If anyone has any objections, please let me know.
-----------
[ 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: Tom Zanussi <zanussi@kernel.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 4bc01a2a9a88..848d9ed6f053 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);
--
2.14.1
next prev parent reply other threads:[~2020-02-27 14:34 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-27 14:33 [PATCH RT 00/23] Linux v4.14.170-rt75-rc2 zanussi
2020-02-27 14:33 ` [PATCH RT 01/23] Fix wrong-variable use in irq_set_affinity_notifier zanussi
2020-02-27 14:33 ` [PATCH RT 02/23] i2c: exynos5: Remove IRQF_ONESHOT zanussi
2020-02-27 14:33 ` [PATCH RT 03/23] i2c: hix5hd2: " zanussi
2020-02-27 14:33 ` [PATCH RT 04/23] x86: preempt: Check preemption level before looking at lazy-preempt zanussi
2020-02-27 14:33 ` [PATCH RT 05/23] sched: migrate_dis/enable: Use sleeping_lock…() to annotate sleeping points zanussi
2020-02-27 14:33 ` [PATCH RT 06/23] sched: __set_cpus_allowed_ptr: Check cpus_mask, not cpus_ptr zanussi
2020-02-27 14:33 ` [PATCH RT 07/23] sched: Remove dead __migrate_disabled() check zanussi
2020-02-27 14:33 ` [PATCH RT 08/23] sched: migrate disable: Protect cpus_ptr with lock zanussi
2020-02-27 14:33 ` [PATCH RT 09/23] lib/smp_processor_id: Don't use cpumask_equal() zanussi
2020-02-27 14:33 ` [PATCH RT 10/23] futex: Make the futex_hash_bucket spinlock_t again and bring back its old state zanussi
2020-02-27 14:33 ` [PATCH RT 11/23] locking/rtmutex: Clean ->pi_blocked_on in the error case zanussi
2020-02-27 14:33 ` [PATCH RT 12/23] lib/ubsan: Don't seralize UBSAN report zanussi
2020-02-27 14:33 ` [PATCH RT 13/23] kmemleak: Change the lock of kmemleak_object to raw_spinlock_t zanussi
2020-02-27 14:33 ` [PATCH RT 14/23] Revert "ARM: Initialize split page table locks for vector page" zanussi
2020-02-27 14:33 ` zanussi [this message]
2020-02-27 14:33 ` [PATCH RT 16/23] sched: migrate_enable: Use select_fallback_rq() zanussi
2020-02-27 14:33 ` [PATCH RT 17/23] sched: Lazy migrate_disable processing zanussi
2020-02-27 14:33 ` [PATCH RT 18/23] sched: migrate_enable: Use stop_one_cpu_nowait() zanussi
2020-02-27 14:33 ` [PATCH RT 19/23] sched/core: migrate_enable() must access takedown_cpu_task on !HOTPLUG_CPU zanussi
2020-02-27 14:33 ` [PATCH RT 20/23] lib/smp_processor_id: Adjust check_preemption_disabled() zanussi
2020-02-27 14:33 ` [PATCH RT 21/23] sched: migrate_enable: Busy loop until the migration request is completed zanussi
2020-03-03 19:56 ` Scott Wood
2020-03-03 20:39 ` Tom Zanussi
2020-03-03 21:19 ` Scott Wood
2020-03-03 21:54 ` Steven Rostedt
2020-03-05 13:38 ` David Laight
2020-03-05 17:58 ` Tom Zanussi
2020-02-27 14:33 ` [PATCH RT 22/23] sched/deadline: Ensure inactive_timer runs in hardirq context zanussi
2020-02-27 14:33 ` [PATCH RT 23/23] Linux 4.14.170-rt75-rc2 zanussi
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=186fec3947a0cc8b99cbf8211a91c52140813302.1582814004.git.zanussi@kernel.org \
--to=zanussi@kernel.org \
--cc=C.Emde@osadl.org \
--cc=bigeasy@linutronix.de \
--cc=jkacur@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-rt-users@vger.kernel.org \
--cc=rostedt@goodmis.org \
--cc=tglx@linutronix.de \
--cc=wagi@monom.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).