Index: kernel/arch/ia32/include/barrier.h
===================================================================
--- kernel/arch/ia32/include/barrier.h	(revision f902d362683090a4d4d8714b068ea5f2987efb8c)
+++ kernel/arch/ia32/include/barrier.h	(revision 3a3d4ca595a9beb21ff6843f12c73a08d87978e7)
@@ -54,4 +54,5 @@
 NO_TRACE static inline void cpuid_serialization(void)
 {
+#ifndef __IN_SHARED_LIBC__
 	asm volatile (
 		"xorl %%eax, %%eax\n"
@@ -59,4 +60,14 @@
 		::: "eax", "ebx", "ecx", "edx", "memory"
 	);
+#else
+	/* Must not clobber PIC register ebx */
+	asm volatile (
+		"movl %%ebx, %%esi\n"
+		"xorl %%eax, %%eax\n"
+		"cpuid\n"
+		"movl %%esi, %%ebx\n"
+		::: "eax", "ecx", "edx", "esi", "memory"
+	);
+#endif
 }