diff options
| -rw-r--r-- | include/linux/hung_task.h | 18 | ||||
| -rw-r--r-- | kernel/hung_task.c | 29 | ||||
| -rw-r--r-- | kernel/locking/rwsem.c | 17 |
3 files changed, 50 insertions, 14 deletions
diff --git a/include/linux/hung_task.h b/include/linux/hung_task.h index 1bc2b3244613..34e615c76ca5 100644 --- a/include/linux/hung_task.h +++ b/include/linux/hung_task.h @@ -21,17 +21,17 @@ * type. * * Type encoding: - * 00 - Blocked on mutex (BLOCKER_TYPE_MUTEX) - * 01 - Blocked on semaphore (BLOCKER_TYPE_SEM) - * 10 - Blocked on rt-mutex (BLOCKER_TYPE_RTMUTEX) - * 11 - Blocked on rw-semaphore (BLOCKER_TYPE_RWSEM) + * 00 - Blocked on mutex (BLOCKER_TYPE_MUTEX) + * 01 - Blocked on semaphore (BLOCKER_TYPE_SEM) + * 10 - Blocked on rw-semaphore as READER (BLOCKER_TYPE_RWSEM_READER) + * 11 - Blocked on rw-semaphore as WRITER (BLOCKER_TYPE_RWSEM_WRITER) */ -#define BLOCKER_TYPE_MUTEX 0x00UL -#define BLOCKER_TYPE_SEM 0x01UL -#define BLOCKER_TYPE_RTMUTEX 0x02UL -#define BLOCKER_TYPE_RWSEM 0x03UL +#define BLOCKER_TYPE_MUTEX 0x00UL +#define BLOCKER_TYPE_SEM 0x01UL +#define BLOCKER_TYPE_RWSEM_READER 0x02UL +#define BLOCKER_TYPE_RWSEM_WRITER 0x03UL -#define BLOCKER_TYPE_MASK 0x03UL +#define BLOCKER_TYPE_MASK 0x03UL #ifdef CONFIG_DETECT_HUNG_TASK_BLOCKER static inline void hung_task_set_blocker(void *lock, unsigned long type) diff --git a/kernel/hung_task.c b/kernel/hung_task.c index d2432df2b905..8708a1205f82 100644 --- a/kernel/hung_task.c +++ b/kernel/hung_task.c @@ -23,6 +23,7 @@ #include <linux/sched/debug.h> #include <linux/sched/sysctl.h> #include <linux/hung_task.h> +#include <linux/rwsem.h> #include <trace/events/sched.h> @@ -100,6 +101,7 @@ static void debug_show_blocker(struct task_struct *task) { struct task_struct *g, *t; unsigned long owner, blocker, blocker_type; + const char *rwsem_blocked_by, *rwsem_blocked_as; RCU_LOCKDEP_WARN(!rcu_read_lock_held(), "No rcu lock held"); @@ -111,12 +113,20 @@ static void debug_show_blocker(struct task_struct *task) switch (blocker_type) { case BLOCKER_TYPE_MUTEX: - owner = mutex_get_owner( - (struct mutex *)hung_task_blocker_to_lock(blocker)); + owner = mutex_get_owner(hung_task_blocker_to_lock(blocker)); break; case BLOCKER_TYPE_SEM: - owner = sem_last_holder( - (struct semaphore *)hung_task_blocker_to_lock(blocker)); + owner = sem_last_holder(hung_task_blocker_to_lock(blocker)); + break; + case BLOCKER_TYPE_RWSEM_READER: + case BLOCKER_TYPE_RWSEM_WRITER: + owner = (unsigned long)rwsem_owner( + hung_task_blocker_to_lock(blocker)); + rwsem_blocked_as = (blocker_type == BLOCKER_TYPE_RWSEM_READER) ? + "reader" : "writer"; + rwsem_blocked_by = is_rwsem_reader_owned( + hung_task_blocker_to_lock(blocker)) ? + "reader" : "writer"; break; default: WARN_ON_ONCE(1); @@ -134,6 +144,11 @@ static void debug_show_blocker(struct task_struct *task) pr_err("INFO: task %s:%d is blocked on a semaphore, but the last holder is not found.\n", task->comm, task->pid); break; + case BLOCKER_TYPE_RWSEM_READER: + case BLOCKER_TYPE_RWSEM_WRITER: + pr_err("INFO: task %s:%d is blocked on an rw-semaphore, but the owner is not found.\n", + task->comm, task->pid); + break; } return; } @@ -152,6 +167,12 @@ static void debug_show_blocker(struct task_struct *task) pr_err("INFO: task %s:%d blocked on a semaphore likely last held by task %s:%d\n", task->comm, task->pid, t->comm, t->pid); break; + case BLOCKER_TYPE_RWSEM_READER: + case BLOCKER_TYPE_RWSEM_WRITER: + pr_err("INFO: task %s:%d <%s> blocked on an rw-semaphore likely owned by task %s:%d <%s>\n", + task->comm, task->pid, rwsem_blocked_as, t->comm, + t->pid, rwsem_blocked_by); + break; } sched_show_task(t); return; diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c index a310eb9896de..92c6332da401 100644 --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -27,6 +27,7 @@ #include <linux/export.h> #include <linux/rwsem.h> #include <linux/atomic.h> +#include <linux/hung_task.h> #include <trace/events/lock.h> #ifndef CONFIG_PREEMPT_RT @@ -1065,10 +1066,13 @@ queue: wake_up_q(&wake_q); trace_contention_begin(sem, LCB_F_READ); + set_current_state(state); + + if (state == TASK_UNINTERRUPTIBLE) + hung_task_set_blocker(sem, BLOCKER_TYPE_RWSEM_READER); /* wait to be given the lock */ for (;;) { - set_current_state(state); if (!smp_load_acquire(&waiter.task)) { /* Matches rwsem_mark_wake()'s smp_store_release(). */ break; @@ -1083,8 +1087,12 @@ queue: } schedule_preempt_disabled(); lockevent_inc(rwsem_sleep_reader); + set_current_state(state); } + if (state == TASK_UNINTERRUPTIBLE) + hung_task_clear_blocker(); + __set_current_state(TASK_RUNNING); lockevent_inc(rwsem_rlock); trace_contention_end(sem, 0); @@ -1146,6 +1154,9 @@ rwsem_down_write_slowpath(struct rw_semaphore *sem, int state) set_current_state(state); trace_contention_begin(sem, LCB_F_WRITE); + if (state == TASK_UNINTERRUPTIBLE) + hung_task_set_blocker(sem, BLOCKER_TYPE_RWSEM_WRITER); + for (;;) { if (rwsem_try_write_lock(sem, &waiter)) { /* rwsem_try_write_lock() implies ACQUIRE on success */ @@ -1179,6 +1190,10 @@ rwsem_down_write_slowpath(struct rw_semaphore *sem, int state) trylock_again: raw_spin_lock_irq(&sem->wait_lock); } + + if (state == TASK_UNINTERRUPTIBLE) + hung_task_clear_blocker(); + __set_current_state(TASK_RUNNING); raw_spin_unlock_irq(&sem->wait_lock); lockevent_inc(rwsem_wlock); |