diff options
Diffstat (limited to 'debian/patches-rt/0310-locking-Make-spinlock_t-and-rwlock_t-a-RCU-section-o.patch')
| -rw-r--r-- | debian/patches-rt/0310-locking-Make-spinlock_t-and-rwlock_t-a-RCU-section-o.patch | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/debian/patches-rt/0310-locking-Make-spinlock_t-and-rwlock_t-a-RCU-section-o.patch b/debian/patches-rt/0310-locking-Make-spinlock_t-and-rwlock_t-a-RCU-section-o.patch new file mode 100644 index 000000000..fa066cce6 --- /dev/null +++ b/debian/patches-rt/0310-locking-Make-spinlock_t-and-rwlock_t-a-RCU-section-o.patch @@ -0,0 +1,125 @@ +From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Date: Tue, 19 Nov 2019 09:25:04 +0100 +Subject: [PATCH 310/342] locking: Make spinlock_t and rwlock_t a RCU section + on RT +Origin: https://git.kernel.org/cgit/linux/kernel/git/rt/linux-stable-rt.git/commit?id=5a4cb6344d94ce566d562e036d4fd69ead0338f3 + +[ 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 dc95a81ae3a6..fe5153fc7665 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); |