diff options
| -rw-r--r-- | include/linux/sched.h | 46 | ||||
| -rw-r--r-- | kernel/sched/core.c | 13 |
2 files changed, 57 insertions, 2 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index 320a9779f1b4..4648e07f7d6f 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -243,6 +243,43 @@ extern char ___assert_task_state[1 - 2*!!( ((task->state & TASK_UNINTERRUPTIBLE) != 0 && \ (task->flags & PF_FROZEN) == 0) +#ifdef CONFIG_DEBUG_ATOMIC_SLEEP + +#define __set_task_state(tsk, state_value) \ + do { \ + (tsk)->task_state_change = _THIS_IP_; \ + (tsk)->state = (state_value); \ + } while (0) +#define set_task_state(tsk, state_value) \ + do { \ + (tsk)->task_state_change = _THIS_IP_; \ + set_mb((tsk)->state, (state_value)); \ + } while (0) + +/* + * set_current_state() includes a barrier so that the write of current->state + * is correctly serialised wrt the caller's subsequent test of whether to + * actually sleep: + * + * set_current_state(TASK_UNINTERRUPTIBLE); + * if (do_i_need_to_sleep()) + * schedule(); + * + * If the caller does not need such serialisation then use __set_current_state() + */ +#define __set_current_state(state_value) \ + do { \ + current->task_state_change = _THIS_IP_; \ + current->state = (state_value); \ + } while (0) +#define set_current_state(state_value) \ + do { \ + current->task_state_change = _THIS_IP_; \ + set_mb(current->state, (state_value)); \ + } while (0) + +#else + #define __set_task_state(tsk, state_value) \ do { (tsk)->state = (state_value); } while (0) #define set_task_state(tsk, state_value) \ @@ -259,11 +296,13 @@ extern char ___assert_task_state[1 - 2*!!( * * If the caller does not need such serialisation then use __set_current_state() */ -#define __set_current_state(state_value) \ +#define __set_current_state(state_value) \ do { current->state = (state_value); } while (0) -#define set_current_state(state_value) \ +#define set_current_state(state_value) \ set_mb(current->state, (state_value)) +#endif + /* Task command name length */ #define TASK_COMM_LEN 16 @@ -1661,6 +1700,9 @@ struct task_struct { unsigned int sequential_io; unsigned int sequential_io_avg; #endif +#ifdef CONFIG_DEBUG_ATOMIC_SLEEP + unsigned long task_state_change; +#endif }; /* Future-safe accessor for struct task_struct's cpus_allowed. */ diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 0456a55fc27f..5b4b96b27cd7 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7298,6 +7298,19 @@ void __might_sleep(const char *file, int line, int preempt_offset) { static unsigned long prev_jiffy; /* ratelimiting */ + /* + * Blocking primitives will set (and therefore destroy) current->state, + * since we will exit with TASK_RUNNING make sure we enter with it, + * otherwise we will destroy state. + */ + if (WARN(current->state != TASK_RUNNING, + "do not call blocking ops when !TASK_RUNNING; " + "state=%lx set at [<%p>] %pS\n", + current->state, + (void *)current->task_state_change, + (void *)current->task_state_change)) + __set_current_state(TASK_RUNNING); + rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */ if ((preempt_count_equals(preempt_offset) && !irqs_disabled() && !is_idle_task(current)) || |