diff options
Diffstat (limited to 'debian/patches-rt/0228-locking-Make-spinlock_t-and-rwlock_t-a-RCU-section-o.patch')
| -rw-r--r-- | debian/patches-rt/0228-locking-Make-spinlock_t-and-rwlock_t-a-RCU-section-o.patch | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/debian/patches-rt/0228-locking-Make-spinlock_t-and-rwlock_t-a-RCU-section-o.patch b/debian/patches-rt/0228-locking-Make-spinlock_t-and-rwlock_t-a-RCU-section-o.patch new file mode 100644 index 000000000..77ce72c24 --- /dev/null +++ b/debian/patches-rt/0228-locking-Make-spinlock_t-and-rwlock_t-a-RCU-section-o.patch @@ -0,0 +1,126 @@ +From 166485c3d38dd51a1a9a35edb7b2d3c1054a2418 Mon Sep 17 00:00:00 2001 +From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Date: Tue, 19 Nov 2019 09:25:04 +0100 +Subject: [PATCH 228/323] locking: Make spinlock_t and rwlock_t a RCU section + on RT +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz + +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> +--- + 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 2fe178651254..31b374d36d04 100644 +--- a/kernel/locking/rtmutex.c ++++ b/kernel/locking/rtmutex.c +@@ -1136,6 +1136,7 @@ void __lockfunc rt_spin_lock(spinlock_t *lock) + { + spin_acquire(&lock->dep_map, 0, 0, _RET_IP_); + rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock); ++ rcu_read_lock(); + migrate_disable(); + } + EXPORT_SYMBOL(rt_spin_lock); +@@ -1150,6 +1151,7 @@ void __lockfunc rt_spin_lock_nested(spinlock_t *lock, int subclass) + { + spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_); + rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock); ++ rcu_read_lock(); + migrate_disable(); + } + EXPORT_SYMBOL(rt_spin_lock_nested); +@@ -1159,6 +1161,7 @@ void __lockfunc rt_spin_lock_nest_lock(spinlock_t *lock, + { + spin_acquire_nest(&lock->dep_map, 0, 0, nest_lock, _RET_IP_); + rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock); ++ rcu_read_lock(); + migrate_disable(); + } + EXPORT_SYMBOL(rt_spin_lock_nest_lock); +@@ -1169,6 +1172,7 @@ void __lockfunc rt_spin_unlock(spinlock_t *lock) + /* NOTE: we always pass in '1' for nested, for simplicity */ + spin_release(&lock->dep_map, _RET_IP_); + migrate_enable(); ++ rcu_read_unlock(); + rt_spin_lock_fastunlock(&lock->lock, rt_spin_lock_slowunlock); + } + EXPORT_SYMBOL(rt_spin_unlock); +@@ -1198,6 +1202,7 @@ 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(); + migrate_disable(); + } + return ret; +@@ -1212,6 +1217,7 @@ int __lockfunc rt_spin_trylock_bh(spinlock_t *lock) + ret = __rt_mutex_trylock(&lock->lock); + if (ret) { + spin_acquire(&lock->dep_map, 0, 1, _RET_IP_); ++ rcu_read_lock(); + migrate_disable(); + } else { + local_bh_enable(); +diff --git a/kernel/locking/rwlock-rt.c b/kernel/locking/rwlock-rt.c +index 16be7111aae7..3d2d1f14b513 100644 +--- a/kernel/locking/rwlock-rt.c ++++ b/kernel/locking/rwlock-rt.c +@@ -270,6 +270,7 @@ int __lockfunc rt_read_trylock(rwlock_t *rwlock) + ret = __read_rt_trylock(rwlock); + if (ret) { + rwlock_acquire_read(&rwlock->dep_map, 0, 1, _RET_IP_); ++ rcu_read_lock(); + migrate_disable(); + } + return ret; +@@ -283,6 +284,7 @@ int __lockfunc rt_write_trylock(rwlock_t *rwlock) + ret = __write_rt_trylock(rwlock); + if (ret) { + rwlock_acquire(&rwlock->dep_map, 0, 1, _RET_IP_); ++ rcu_read_lock(); + migrate_disable(); + } + return ret; +@@ -293,6 +295,7 @@ void __lockfunc rt_read_lock(rwlock_t *rwlock) + { + rwlock_acquire_read(&rwlock->dep_map, 0, 0, _RET_IP_); + __read_rt_lock(rwlock); ++ rcu_read_lock(); + migrate_disable(); + } + EXPORT_SYMBOL(rt_read_lock); +@@ -301,6 +304,7 @@ void __lockfunc rt_write_lock(rwlock_t *rwlock) + { + rwlock_acquire(&rwlock->dep_map, 0, 0, _RET_IP_); + __write_rt_lock(rwlock); ++ rcu_read_lock(); + migrate_disable(); + } + EXPORT_SYMBOL(rt_write_lock); +@@ -309,6 +313,7 @@ void __lockfunc rt_read_unlock(rwlock_t *rwlock) + { + rwlock_release(&rwlock->dep_map, _RET_IP_); + migrate_enable(); ++ rcu_read_unlock(); + __read_rt_unlock(rwlock); + } + EXPORT_SYMBOL(rt_read_unlock); +@@ -317,6 +322,7 @@ void __lockfunc rt_write_unlock(rwlock_t *rwlock) + { + rwlock_release(&rwlock->dep_map, _RET_IP_); + migrate_enable(); ++ rcu_read_unlock(); + __write_rt_unlock(rwlock); + } + EXPORT_SYMBOL(rt_write_unlock); +-- +2.43.0 + |