[PATCH 3/5] sched: Detect call to schedule from critical entry code

[Frederic Weisbecker]

Detect calls to schedule() between user_enter() and user_exit(). Those
are symptoms of early entry code that either forgot to protect a call
to schedule() inside exception_enter()/exception_exit() or, in the case
of HAVE_CONTEXT_TRACKING_OFFSTACK, enabled interrupts or preemption in
a wrong spot.

Signed-off-by: Frederic Weisbecker <frede...@kernel.org>
Cc: Marcelo Tosatti <mtosa...@redhat.com>
Cc: Paul E. McKenney <paul...@kernel.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Phil Auld <pa...@redhat.com>
Cc: Thomas Gleixner <t...@linutronix.de>
---
 kernel/sched/core.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index d2003a7d5ab5..c23d7cb5aee3 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4291,6 +4291,7 @@ static inline void schedule_debug(struct task_struct 
*prev, bool preempt)
                preempt_count_set(PREEMPT_DISABLED);
        }
        rcu_sleep_check();
+       SCHED_WARN_ON(ct_state() == CONTEXT_USER);
 
        profile_hit(SCHED_PROFILING, __builtin_return_address(0));
 
-- 
2.25.1