+ /* Wait for futex wakeup */
+ if (uatomic_read((int32_t *) sock_info->wait_shm_mmap) == 0) {
+ ret = futex_async((int32_t *) sock_info->wait_shm_mmap,
+ FUTEX_WAIT, 0, NULL, NULL, 0);
+ if (ret < 0) {
+ if (errno == EFAULT) {
+ wait_poll_fallback = 1;
+ ERR(
+"Linux kernels 2.6.33 to 3.0 (with the exception of stable versions) "
+"do not support FUTEX_WAKE on read-only memory mappings correctly. "
+"Please upgrade your kernel "
+"(fix is commit 9ea71503a8ed9184d2d0b8ccc4d269d05f7940ae in Linux kernel "
+"mainline). LTTng-UST will use polling mode fallback.");
+ }
+ PERROR("futex");
+ }
+ }