Index: uspace/lib/c/generic/rtld/module.c
===================================================================
--- uspace/lib/c/generic/rtld/module.c	(revision eff458dc0610e2e236a23436d7688091d3843237)
+++ uspace/lib/c/generic/rtld/module.c	(revision bf0716fb24686e0ffa4f402f6a89bd163f14b753)
@@ -403,5 +403,9 @@
 	rtld->tls_size = ALIGN_UP(rtld->tls_size, rtld->tls_align);
 
-	/* Space for the TCB. */
+	/* Space for the TCB.
+	 * Later, the TLS zero offset is equal to the pointer to tcb_t, so
+	 * adding the sizeof(tcb_t) block AFTER we calculated the alignment
+	 * of the remainder above is correct.
+	 */
 	rtld->tls_size += sizeof(tcb_t);
 #endif