[PATCH] lockdep: Do no validate wait context for novalidate class

From: Sebastian Andrzej Siewior
Date: Mon Jun 29 2020 - 16:15:59 EST


The novalidate class is ignored in the lockchain validation but is
considered in the wait context validation.
If a mutex and a spinlock_t is ignored by using
lockdep_set_novalidate_class() then both locks will share the same lock
class. From the wait validation point of view the mutex will then appear
like a spinlock_t and the validator will complain if another mutex will
be acquired.

Ignore the nonvalidate locks from wait context checking.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
---
kernel/locking/lockdep.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 29a8de4c50b90..fb9a642d8ebef 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -4067,7 +4067,7 @@ static int check_wait_context(struct task_struct *curr, struct held_lock *next)
*/
for (depth = curr->lockdep_depth - 1; depth >= 0; depth--) {
struct held_lock *prev = curr->held_locks + depth;
- if (prev->irq_context != next->irq_context)
+ if (prev->check && prev->irq_context != next->irq_context)
break;
}
depth++;
@@ -4078,6 +4078,9 @@ static int check_wait_context(struct task_struct *curr, struct held_lock *next)
struct held_lock *prev = curr->held_locks + depth;
short prev_inner = hlock_class(prev)->wait_type_inner;

+ if (!prev->check)
+ continue;
+
if (prev_inner) {
/*
* We can have a bigger inner than a previous one
--
2.27.0