Fix tsan failures
diff --git a/src/core/lib/iomgr/ev_epoll_linux.c b/src/core/lib/iomgr/ev_epoll_linux.c
index a8a874c..35a15e0 100644
--- a/src/core/lib/iomgr/ev_epoll_linux.c
+++ b/src/core/lib/iomgr/ev_epoll_linux.c
@@ -236,6 +236,17 @@
static gpr_mu g_pi_freelist_mu;
static polling_island *g_pi_freelist = NULL;
+#ifdef _GRPC_TSAN
+/* Currently TSAN may incorrectly flag data races between epoll_ctl and
+ epoll_wait for any grpc_fd structs that are added to the epoll set via
+ epoll_ctl and are returned (within a very short window) via epoll_wait().
+
+ To work-around this race, we establish a happens-before relation between
+ the code just-before epoll_ctl() and the code after epoll_wait() by using
+ this atomic */
+gpr_atm g_epoll_sync;
+#endif
+
/* The caller is expected to hold pi->mu lock before calling this function */
static void polling_island_add_fds_locked(polling_island *pi, grpc_fd **fds,
size_t fd_count, bool add_fd_refs) {
@@ -243,6 +254,11 @@
size_t i;
struct epoll_event ev;
+#ifdef _GRPC_TSAN
+ /* See the definition of g_epoll_sync for more context */
+ gpr_atm_rel_store(&g_epoll_sync, 0);
+#endif
+
for (i = 0; i < fd_count; i++) {
ev.events = (uint32_t)(EPOLLIN | EPOLLOUT | EPOLLET);
ev.data.ptr = fds[i];
@@ -361,6 +377,7 @@
}
pi->epoll_fd = epoll_create1(EPOLL_CLOEXEC);
+
if (pi->epoll_fd < 0) {
gpr_log(GPR_ERROR, "epoll_create1() failed with error: %s",
strerror(errno));
@@ -1144,6 +1161,11 @@
}
}
+#ifdef _GRPC_TSAN
+ /* See the definition of g_poll_sync for more details */
+ gpr_atm_acq_load(&g_epoll_sync);
+#endif
+
for (int i = 0; i < ep_rv; ++i) {
void *data_ptr = ep_ev[i].data.ptr;
if (data_ptr == &grpc_global_wakeup_fd) {
@@ -1514,10 +1536,13 @@
return &vtable;
}
-#else /* defined(GPR_LINUX_EPOLL) */
+#else /* defined(GPR_LINUX_EPOLL) */
+#if defined(GPR_POSIX_SOCKET)
+#include "src/core/lib/iomgr/ev_posix.h"
/* If GPR_LINUX_EPOLL is not defined, it means epoll is not available. Return
* NULL */
const grpc_event_engine_vtable *grpc_init_epoll_linux(void) { return NULL; }
+#endif /* defined(GPR_POSIX_SOCKET) */
void grpc_use_signal(int signum) {}
#endif /* !defined(GPR_LINUX_EPOLL) */