diff options
| -rw-r--r-- | include/linux/rhashtable-types.h | 3 | ||||
| -rw-r--r-- | include/linux/rhashtable.h | 3 | ||||
| -rw-r--r-- | lib/rhashtable.c | 31 |
3 files changed, 33 insertions, 4 deletions
diff --git a/include/linux/rhashtable-types.h b/include/linux/rhashtable-types.h index 72082428d6c6..fc2f596a6df1 100644 --- a/include/linux/rhashtable-types.h +++ b/include/linux/rhashtable-types.h @@ -12,6 +12,7 @@ #include <linux/alloc_tag.h> #include <linux/atomic.h> #include <linux/compiler.h> +#include <linux/irq_work_types.h> #include <linux/mutex.h> #include <linux/workqueue_types.h> @@ -77,6 +78,7 @@ struct rhashtable_params { * @p: Configuration parameters * @rhlist: True if this is an rhltable * @run_work: Deferred worker to expand/shrink asynchronously + * @run_irq_work: Bounces the @run_work kick through hard IRQ context. * @mutex: Mutex to protect current/future table swapping * @lock: Spin lock to protect walker list * @nelems: Number of elements in table @@ -88,6 +90,7 @@ struct rhashtable { struct rhashtable_params p; bool rhlist; struct work_struct run_work; + struct irq_work run_irq_work; struct mutex mutex; spinlock_t lock; atomic_t nelems; diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h index 7def3f0f556b..ef5230cece36 100644 --- a/include/linux/rhashtable.h +++ b/include/linux/rhashtable.h @@ -20,6 +20,7 @@ #include <linux/err.h> #include <linux/errno.h> +#include <linux/irq_work.h> #include <linux/jhash.h> #include <linux/list_nulls.h> #include <linux/workqueue.h> @@ -847,7 +848,7 @@ slow_path: rht_assign_unlock(tbl, bkt, obj, flags); if (rht_grow_above_75(ht, tbl)) - schedule_work(&ht->run_work); + irq_work_queue(&ht->run_irq_work); data = NULL; out: diff --git a/lib/rhashtable.c b/lib/rhashtable.c index fb2b7bc137ba..7a67ef5b67b6 100644 --- a/lib/rhashtable.c +++ b/lib/rhashtable.c @@ -441,10 +441,33 @@ static void rht_deferred_worker(struct work_struct *work) mutex_unlock(&ht->mutex); + /* + * Re-arm via @run_work, not @run_irq_work. + * rhashtable_free_and_destroy() drains async work as irq_work_sync() + * followed by cancel_work_sync(). If this site queued irq_work while + * cancel_work_sync() was waiting for us, irq_work_sync() would already + * have returned and the stale irq_work could fire post-teardown. + * cancel_work_sync() natively handles self-requeue on @run_work. + */ if (err) schedule_work(&ht->run_work); } +/* + * Insert-path callers can run under a raw spinlock (e.g. an insecure_elasticity + * user). Calling schedule_work() under that lock records caller_lock -> + * pool->lock -> pi_lock -> rq->__lock, closing a locking cycle if any of + * these is acquired in the reverse direction elsewhere. Bounce through + * irq_work so the schedule_work() runs with the caller's lock no longer held. + */ +static void rht_deferred_irq_work(struct irq_work *irq_work) +{ + struct rhashtable *ht = container_of(irq_work, struct rhashtable, + run_irq_work); + + schedule_work(&ht->run_work); +} + static int rhashtable_insert_rehash(struct rhashtable *ht, struct bucket_table *tbl) { @@ -477,7 +500,7 @@ static int rhashtable_insert_rehash(struct rhashtable *ht, if (err == -EEXIST) err = 0; } else - schedule_work(&ht->run_work); + irq_work_queue(&ht->run_irq_work); return err; @@ -488,7 +511,7 @@ fail: /* Schedule async rehash to retry allocation in process context. */ if (err == -ENOMEM) - schedule_work(&ht->run_work); + irq_work_queue(&ht->run_irq_work); return err; } @@ -630,7 +653,7 @@ static void *rhashtable_try_insert(struct rhashtable *ht, const void *key, rht_unlock(tbl, bkt, flags); if (inserted && rht_grow_above_75(ht, tbl)) - schedule_work(&ht->run_work); + irq_work_queue(&ht->run_irq_work); } } while (!IS_ERR_OR_NULL(new_tbl)); @@ -1085,6 +1108,7 @@ int rhashtable_init_noprof(struct rhashtable *ht, RCU_INIT_POINTER(ht->tbl, tbl); INIT_WORK(&ht->run_work, rht_deferred_worker); + init_irq_work(&ht->run_irq_work, rht_deferred_irq_work); return 0; } @@ -1150,6 +1174,7 @@ void rhashtable_free_and_destroy(struct rhashtable *ht, struct bucket_table *tbl, *next_tbl; unsigned int i; + irq_work_sync(&ht->run_irq_work); cancel_work_sync(&ht->run_work); mutex_lock(&ht->mutex); |