From b2e9c8eea5d4f4edb43ae7be9e15986dbfce5b95 Mon Sep 17 00:00:00 2001 From: Frans Kaashoek Date: Mon, 22 Jul 2019 15:38:08 -0400 Subject: Clear U bit for second stack page so that it functions as a guard page --- kernel/exec.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel/exec.c') diff --git a/kernel/exec.c b/kernel/exec.c index b21afbb..c25dfb0 100644 --- a/kernel/exec.c +++ b/kernel/exec.c @@ -68,6 +68,7 @@ exec(char *path, char **argv) sz = PGROUNDUP(sz); if((sz = uvmalloc(pagetable, sz, sz + 2*PGSIZE)) == 0) goto bad; + clearpteu(pagetable, sz-2*PGSIZE); sp = sz; stackbase = sp - PGSIZE; -- cgit v1.2.3