diff --git a/[refs] b/[refs]
index 64893fe8d562..fe1a5df6b707 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 63e1fd41c7127650d355e7db7dd92890edf5523b
+refs/heads/master: f9a3879abf2f1a27c39915e6074b8ff15a24cb55
diff --git a/trunk/kernel/fork.c b/trunk/kernel/fork.c
index a8eab86de7f1..ccdfbb16c86d 100644
--- a/trunk/kernel/fork.c
+++ b/trunk/kernel/fork.c
@@ -1061,6 +1061,12 @@ static task_t *copy_process(unsigned long clone_flags,
 	 */
 	p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NULL;
 
+	/*
+	 * sigaltstack should be cleared when sharing the same VM
+	 */
+	if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM)
+		p->sas_ss_sp = p->sas_ss_size = 0;
+
 	/*
 	 * Syscall tracing should be turned off in the child regardless
 	 * of CLONE_PTRACE.