diff --git a/libc/kernel/uapi/linux/seccomp.h b/libc/kernel/uapi/linux/seccomp.h
index 6f7cbbe..d535f50 100644
--- a/libc/kernel/uapi/linux/seccomp.h
+++ b/libc/kernel/uapi/linux/seccomp.h
@@ -31,6 +31,7 @@
 #define SECCOMP_FILTER_FLAG_LOG (1UL << 1)
 #define SECCOMP_FILTER_FLAG_SPEC_ALLOW (1UL << 2)
 #define SECCOMP_FILTER_FLAG_NEW_LISTENER (1UL << 3)
+#define SECCOMP_FILTER_FLAG_TSYNC_ESRCH (1UL << 4)
 #define SECCOMP_RET_KILL_PROCESS 0x80000000U
 #define SECCOMP_RET_KILL_THREAD 0x00000000U
 #define SECCOMP_RET_KILL SECCOMP_RET_KILL_THREAD