Index: uspace/lib/c/arch/amd64/include/elf_linux.h
===================================================================
--- uspace/lib/c/arch/amd64/include/elf_linux.h	(revision 9bcdbc542af346e7ee2aca8b5d53c39f4f87df4e)
+++ uspace/lib/c/arch/amd64/include/elf_linux.h	(revision fd418d9c9df736e34fdfef1cd5f55e0f3406b693)
@@ -66,4 +66,16 @@
 	uint64_t rsp;
 	uint64_t ss;
+
+	/*
+	 * The following registers need to be part of elf_regs_t.
+	 * Unfortunately, we don't have any information about them in our
+	 * istate_t.
+	 */
+	uint64_t unused_fs_base;
+	uint64_t unused_gs_base;
+	uint64_t unused_ds;
+	uint64_t unused_es;
+	uint64_t unused_fs;
+	uint64_t unused_gs;
 } elf_regs_t;
 
@@ -91,4 +103,14 @@
 	elf_regs->rsp = istate->rsp;
 	elf_regs->ss = istate->ss;
+
+	/*
+	 * Reset the registers for which there is not enough info in istate_t.
+	 */
+	elf_regs->unused_fs_base = 0;
+	elf_regs->unused_gs_base = 0;
+	elf_regs->unused_ds = 0;
+	elf_regs->unused_es = 0;
+	elf_regs->unused_fs = 0;
+	elf_regs->unused_gs = 0;
 }