The following commit has been merged into the locking/core branch of tip:
Commit-ID: 45f67f30a22f264bc7a0a61255c2ee1a838e9403
Gitweb: https://git.kernel.org/tip/45f67f30a22f264bc7a0a61255c2ee1a838e9403
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Fri, 08 Sep 2023 18:22:53 +02:00
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Wed, 20 Sep 2023 09:31:14 +02:00
locking/rtmutex: Add a lockdep assert to catch potential nested blocking
There used to be a BUG_ON(current->pi_blocked_on) in the lock acquisition
functions, but that vanished in one of the rtmutex overhauls.
Bring it back in form of a lockdep assert to catch code paths which take
rtmutex based locks with current::pi_blocked_on != NULL.
Reported-by: Crystal Wood <swood@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: "Peter Zijlstra (Intel)" <peterz@xxxxxxxxxxxxx>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/20230908162254.999499-7-bigeasy@xxxxxxxxxxxxx
---
kernel/locking/rtmutex.c | 2 ++
kernel/locking/rwbase_rt.c | 2 ++
kernel/locking/spinlock_rt.c | 2 ++
3 files changed, 6 insertions(+)
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index a3fe05d..4a10e8c 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1784,6 +1784,8 @@ static int __sched rt_mutex_slowlock(struct rt_mutex_base *lock,
static __always_inline int __rt_mutex_lock(struct rt_mutex_base *lock,
unsigned int state)
{
+ lockdep_assert(!current->pi_blocked_on);
+
if (likely(rt_mutex_try_acquire(lock)))
return 0;
diff --git a/kernel/locking/rwbase_rt.c b/kernel/locking/rwbase_rt.c
index c7258cb..34a5956 100644
--- a/kernel/locking/rwbase_rt.c
+++ b/kernel/locking/rwbase_rt.c
@@ -133,6 +133,8 @@ static int __sched __rwbase_read_lock(struct rwbase_rt *rwb,
static __always_inline int rwbase_read_lock(struct rwbase_rt *rwb,
unsigned int state)
{
+ lockdep_assert(!current->pi_blocked_on);
+
if (rwbase_read_trylock(rwb))
return 0;
diff --git a/kernel/locking/spinlock_rt.c b/kernel/locking/spinlock_rt.c
index 842037b..38e2924 100644
--- a/kernel/locking/spinlock_rt.c
+++ b/kernel/locking/spinlock_rt.c
@@ -37,6 +37,8 @@
static __always_inline void rtlock_lock(struct rt_mutex_base *rtm)
{
+ lockdep_assert(!current->pi_blocked_on);
+
if (unlikely(!rt_mutex_cmpxchg_acquire(rtm, NULL, current)))
rtlock_slowlock(rtm);
}
|