diff --git a/include/qemu/coroutine_int.h b/include/qemu/coroutine_int.h index cb98892bba..59e8406398 100644 --- a/include/qemu/coroutine_int.h +++ b/include/qemu/coroutine_int.h @@ -46,14 +46,21 @@ struct Coroutine { size_t locks_held; + /* Only used when the coroutine has yielded. */ + AioContext *ctx; + + /* Used to catch and abort on illegal co-routine entry. + * Will contain the name of the function that had first + * scheduled the coroutine. */ + const char *scheduled; + + QSIMPLEQ_ENTRY(Coroutine) co_queue_next; + /* Coroutines that should be woken up when we yield or terminate. * Only used when the coroutine is running. */ QSIMPLEQ_HEAD(, Coroutine) co_queue_wakeup; - /* Only used when the coroutine has yielded. */ - AioContext *ctx; - QSIMPLEQ_ENTRY(Coroutine) co_queue_next; QSLIST_ENTRY(Coroutine) co_scheduled_next; }; diff --git a/util/async.c b/util/async.c index 0e1bd8780a..4dd9d95a9e 100644 --- a/util/async.c +++ b/util/async.c @@ -388,6 +388,9 @@ static void co_schedule_bh_cb(void *opaque) QSLIST_REMOVE_HEAD(&straight, co_scheduled_next); trace_aio_co_schedule_bh_cb(ctx, co); aio_context_acquire(ctx); + + /* Protected by write barrier in qemu_aio_coroutine_enter */ + atomic_set(&co->scheduled, NULL); qemu_coroutine_enter(co); aio_context_release(ctx); } @@ -438,6 +441,16 @@ fail: void aio_co_schedule(AioContext *ctx, Coroutine *co) { trace_aio_co_schedule(ctx, co); + const char *scheduled = atomic_cmpxchg(&co->scheduled, NULL, + __func__); + + if (scheduled) { + fprintf(stderr, + "%s: Co-routine was already scheduled in '%s'\n", + __func__, scheduled); + abort(); + } + QSLIST_INSERT_HEAD_ATOMIC(&ctx->scheduled_coroutines, co, co_scheduled_next); qemu_bh_schedule(ctx->co_schedule_bh); diff --git a/util/qemu-coroutine-sleep.c b/util/qemu-coroutine-sleep.c index 9c5655041b..254349cdbb 100644 --- a/util/qemu-coroutine-sleep.c +++ b/util/qemu-coroutine-sleep.c @@ -13,6 +13,7 @@ #include "qemu/osdep.h" #include "qemu/coroutine.h" +#include "qemu/coroutine_int.h" #include "qemu/timer.h" #include "block/aio.h" @@ -25,6 +26,8 @@ static void co_sleep_cb(void *opaque) { CoSleepCB *sleep_cb = opaque; + /* Write of schedule protected by barrier write in aio_co_schedule */ + atomic_set(&sleep_cb->co->scheduled, NULL); aio_co_wake(sleep_cb->co); } @@ -34,6 +37,15 @@ void coroutine_fn co_aio_sleep_ns(AioContext *ctx, QEMUClockType type, CoSleepCB sleep_cb = { .co = qemu_coroutine_self(), }; + + const char *scheduled = atomic_cmpxchg(&sleep_cb.co->scheduled, NULL, + __func__); + if (scheduled) { + fprintf(stderr, + "%s: Co-routine was already scheduled in '%s'\n", + __func__, scheduled); + abort(); + } sleep_cb.ts = aio_timer_new(ctx, type, SCALE_NS, co_sleep_cb, &sleep_cb); timer_mod(sleep_cb.ts, qemu_clock_get_ns(type) + ns); qemu_coroutine_yield(); diff --git a/util/qemu-coroutine.c b/util/qemu-coroutine.c index d6095c1d5a..9eff7fd450 100644 --- a/util/qemu-coroutine.c +++ b/util/qemu-coroutine.c @@ -107,8 +107,22 @@ void qemu_aio_coroutine_enter(AioContext *ctx, Coroutine *co) Coroutine *self = qemu_coroutine_self(); CoroutineAction ret; + /* Cannot rely on the read barrier for co in aio_co_wake(), as there are + * callers outside of aio_co_wake() */ + const char *scheduled = atomic_mb_read(&co->scheduled); + trace_qemu_aio_coroutine_enter(ctx, self, co, co->entry_arg); + /* if the Coroutine has already been scheduled, entering it again will + * cause us to enter it twice, potentially even after the coroutine has + * been deleted */ + if (scheduled) { + fprintf(stderr, + "%s: Co-routine was already scheduled in '%s'\n", + __func__, scheduled); + abort(); + } + if (co->caller) { fprintf(stderr, "Co-routine re-entered recursively\n"); abort();