diff --git a/sys/alpha/linux/linux.h b/sys/alpha/linux/linux.h
index 3bb46547aed..8887ec36f67 100644
--- a/sys/alpha/linux/linux.h
+++ b/sys/alpha/linux/linux.h
@@ -157,6 +157,9 @@ struct linux_new_utsname {
 #define	LINUX_SIGISMEMBER(set, sig)	SIGISMEMBER(set, sig)
 #define	LINUX_SIGADDSET(set, sig)	SIGADDSET(set, sig)
 
+/* sigaltstack */
+#define LINUX_MINSIGSTKSZ	2048
+
 typedef void	(*linux_handler_t)(int);
 typedef u_long	linux_osigset_t;
 
diff --git a/sys/alpha/linux/linux_machdep.c b/sys/alpha/linux/linux_machdep.c
index 14e8a535730..afcfd4c734f 100644
--- a/sys/alpha/linux/linux_machdep.c
+++ b/sys/alpha/linux/linux_machdep.c
@@ -612,7 +612,8 @@ linux_sigaltstack(p, uap)
 
 	ss = stackgap_alloc(&sg, sizeof(stack_t));
 	ss->ss_sp = lss.ss_sp;
-	ss->ss_size = lss.ss_size;
+	ss->ss_size = (lss.ss_size >= LINUX_MINSIGSTKSZ &&
+	    lss.ss_size < MINSIGSTKSZ) ? MINSIGSTKSZ : lss.ss_size;
 	ss->ss_flags = lss.ss_flags;
 
 	oss = (uap->uoss != NULL)
diff --git a/sys/i386/linux/linux.h b/sys/i386/linux/linux.h
index 3bb46547aed..8887ec36f67 100644
--- a/sys/i386/linux/linux.h
+++ b/sys/i386/linux/linux.h
@@ -157,6 +157,9 @@ struct linux_new_utsname {
 #define	LINUX_SIGISMEMBER(set, sig)	SIGISMEMBER(set, sig)
 #define	LINUX_SIGADDSET(set, sig)	SIGADDSET(set, sig)
 
+/* sigaltstack */
+#define LINUX_MINSIGSTKSZ	2048
+
 typedef void	(*linux_handler_t)(int);
 typedef u_long	linux_osigset_t;
 
diff --git a/sys/i386/linux/linux_machdep.c b/sys/i386/linux/linux_machdep.c
index 14e8a535730..afcfd4c734f 100644
--- a/sys/i386/linux/linux_machdep.c
+++ b/sys/i386/linux/linux_machdep.c
@@ -612,7 +612,8 @@ linux_sigaltstack(p, uap)
 
 	ss = stackgap_alloc(&sg, sizeof(stack_t));
 	ss->ss_sp = lss.ss_sp;
-	ss->ss_size = lss.ss_size;
+	ss->ss_size = (lss.ss_size >= LINUX_MINSIGSTKSZ &&
+	    lss.ss_size < MINSIGSTKSZ) ? MINSIGSTKSZ : lss.ss_size;
 	ss->ss_flags = lss.ss_flags;
 
 	oss = (uap->uoss != NULL)