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authorFrans Kaashoek <[email protected]>2019-07-22 15:38:08 -0400
committerFrans Kaashoek <[email protected]>2019-07-22 15:38:08 -0400
commitb2e9c8eea5d4f4edb43ae7be9e15986dbfce5b95 (patch)
tree22f78e4caee4b4481d30a1b83acd13b84841a06e /kernel/exec.c
parent38b430687cc248d7d2928e3b7cedf9d220b96013 (diff)
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Clear U bit for second stack page so that it functions as a guard page
Diffstat (limited to 'kernel/exec.c')
-rw-r--r--kernel/exec.c1
1 files changed, 1 insertions, 0 deletions
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;