diff --git a/arch/parisc/kernel/signal.c b/arch/parisc/kernel/signal.c
index 2264f68f3c2f9716030cb8fab53487f6db22e667..d9a4d6ffc0a8d52ac88f4a86882a02c356d41cc9 100644
--- a/arch/parisc/kernel/signal.c
+++ b/arch/parisc/kernel/signal.c
@@ -239,6 +239,12 @@ 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));