diff --git a/src/core/iomgr/fd_posix.c b/src/core/iomgr/fd_posix.c index 4ba7c5df943..3edafa0b070 100644 --- a/src/core/iomgr/fd_posix.c +++ b/src/core/iomgr/fd_posix.c @@ -72,6 +72,9 @@ static grpc_fd *fd_freelist = NULL; static gpr_mu fd_freelist_mu; static void freelist_fd(grpc_fd *fd) { + // Note that this function must be called after a release store (or + // full-barrier operation) on refst so that prior actions on the fd are + // ordered before the fd becomes visible to the freelist gpr_mu_lock(&fd_freelist_mu); fd->freelist_next = fd_freelist; fd_freelist = fd; @@ -92,7 +95,6 @@ static grpc_fd *alloc_fd(int fd) { gpr_mu_init(&r->mu); } - gpr_atm_rel_store(&r->refst, 1); r->shutdown = 0; r->read_closure = CLOSURE_NOT_READY; r->write_closure = CLOSURE_NOT_READY; @@ -104,6 +106,11 @@ static grpc_fd *alloc_fd(int fd) { r->on_done_closure = NULL; r->closed = 0; r->released = 0; + // The last operation on r before returning it should be a release-store + // so that all the above fields are globally visible before the value of + // r could escape to another thread. Our refcount itself needs a release-store + // so use this + gpr_atm_rel_store(&r->refst, 1); return r; }