Update Linux to v5.4.148

Sourced from [1]

[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.4.148.tar.gz

Change-Id: Ib3d26c5ba9b022e2e03533005c4fed4d7c30b61b
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/kernel/locking/spinlock_debug.c b/kernel/locking/spinlock_debug.c
index 399669f..472dd46 100644
--- a/kernel/locking/spinlock_debug.c
+++ b/kernel/locking/spinlock_debug.c
@@ -51,19 +51,19 @@
 
 static void spin_dump(raw_spinlock_t *lock, const char *msg)
 {
-	struct task_struct *owner = NULL;
+	struct task_struct *owner = READ_ONCE(lock->owner);
 
-	if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT)
-		owner = lock->owner;
+	if (owner == SPINLOCK_OWNER_INIT)
+		owner = NULL;
 	printk(KERN_EMERG "BUG: spinlock %s on CPU#%d, %s/%d\n",
 		msg, raw_smp_processor_id(),
 		current->comm, task_pid_nr(current));
 	printk(KERN_EMERG " lock: %pS, .magic: %08x, .owner: %s/%d, "
 			".owner_cpu: %d\n",
-		lock, lock->magic,
+		lock, READ_ONCE(lock->magic),
 		owner ? owner->comm : "<none>",
 		owner ? task_pid_nr(owner) : -1,
-		lock->owner_cpu);
+		READ_ONCE(lock->owner_cpu));
 	dump_stack();
 }
 
@@ -80,16 +80,16 @@
 static inline void
 debug_spin_lock_before(raw_spinlock_t *lock)
 {
-	SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
-	SPIN_BUG_ON(lock->owner == current, lock, "recursion");
-	SPIN_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
+	SPIN_BUG_ON(READ_ONCE(lock->magic) != SPINLOCK_MAGIC, lock, "bad magic");
+	SPIN_BUG_ON(READ_ONCE(lock->owner) == current, lock, "recursion");
+	SPIN_BUG_ON(READ_ONCE(lock->owner_cpu) == raw_smp_processor_id(),
 							lock, "cpu recursion");
 }
 
 static inline void debug_spin_lock_after(raw_spinlock_t *lock)
 {
-	lock->owner_cpu = raw_smp_processor_id();
-	lock->owner = current;
+	WRITE_ONCE(lock->owner_cpu, raw_smp_processor_id());
+	WRITE_ONCE(lock->owner, current);
 }
 
 static inline void debug_spin_unlock(raw_spinlock_t *lock)
@@ -99,8 +99,8 @@
 	SPIN_BUG_ON(lock->owner != current, lock, "wrong owner");
 	SPIN_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
 							lock, "wrong CPU");
-	lock->owner = SPINLOCK_OWNER_INIT;
-	lock->owner_cpu = -1;
+	WRITE_ONCE(lock->owner, SPINLOCK_OWNER_INIT);
+	WRITE_ONCE(lock->owner_cpu, -1);
 }
 
 /*
@@ -187,8 +187,8 @@
 
 static inline void debug_write_lock_after(rwlock_t *lock)
 {
-	lock->owner_cpu = raw_smp_processor_id();
-	lock->owner = current;
+	WRITE_ONCE(lock->owner_cpu, raw_smp_processor_id());
+	WRITE_ONCE(lock->owner, current);
 }
 
 static inline void debug_write_unlock(rwlock_t *lock)
@@ -197,8 +197,8 @@
 	RWLOCK_BUG_ON(lock->owner != current, lock, "wrong owner");
 	RWLOCK_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
 							lock, "wrong CPU");
-	lock->owner = SPINLOCK_OWNER_INIT;
-	lock->owner_cpu = -1;
+	WRITE_ONCE(lock->owner, SPINLOCK_OWNER_INIT);
+	WRITE_ONCE(lock->owner_cpu, -1);
 }
 
 void do_raw_write_lock(rwlock_t *lock)