diff --git a/arch/parisc/kernel/signal.c b/arch/parisc/kernel/signal.c
index 02895a8f2c55..92223f9ff05c 100644
--- a/arch/parisc/kernel/signal.c
+++ b/arch/parisc/kernel/signal.c
@@ -238,6 +238,12 @@ setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs,
 #endif
 	
 	usp = (regs->gr[30] & ~(0x01UL));
+#ifdef CONFIG_64BIT
+	if (is_compat_task()) {
+		/* The gcc alloca implementation leaves garbage in the upper 32 bits of sp */
+		usp = (compat_uint_t)usp;
+	}
+#endif
 	/*FIXME: frame_size parameter is unused, remove it. */
 	frame = get_sigframe(&ksig->ka, usp, sizeof(*frame));