From a53fbc9b19eee875c4ef5c3fff85826c73839a6f Mon Sep 17 00:00:00 2001
From: Joshua Saxby <Joshua2.Saxby@live.uwe.ac.uk>
Date: Mon, 2 Dec 2019 16:42:02 +0000
Subject: [PATCH] Fix issue where void pointers were being dereferenced In
calls to move_stack_pointer(), intial_stack_pointer should not be
dereferenced in the call This was causing page faults but this has now been
corrected
---
userprog/populate_stack.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/userprog/populate_stack.c b/userprog/populate_stack.c
index 2ac4652..d82e18f 100644
--- a/userprog/populate_stack.c
+++ b/userprog/populate_stack.c
@@ -29,27 +29,27 @@ void populate_stack(void** stack_pointer, int argc, char** argv) {
memcpy(*stack_pointer, argv[i], strlen(argv[i]) + 1);
}
- move_stack_pointer(*stack_pointer, -4); //Moves the stack pointer back 4
+ move_stack_pointer(stack_pointer, -4); //Moves the stack pointer back 4
(*(int *)(*stack_pointer)) = 0;//sentinel
i = argc;
while (--i >= 0)
{
- move_stack_pointer(*stack_pointer, -4); //32bit Moves the stack pointer back 4
+ move_stack_pointer(stack_pointer, -4); //32bit Moves the stack pointer back 4
(*(uint32_t **)(*stack_pointer)) = arr[i];
}
- move_stack_pointer(*stack_pointer, -4);
- move_stack_pointer(*stack_pointer, 4); //Moves the stack pointer forwards 4
+ move_stack_pointer(stack_pointer, -4);
+ move_stack_pointer(stack_pointer, 4); //Moves the stack pointer forwards 4
// TODO: Test if still required in later version
(*(uintptr_t **)(*stack_pointer)) = *stack_pointer;
- move_stack_pointer(*stack_pointer, -4); //Moves the stack pointer back 4
+ move_stack_pointer(stack_pointer, -4); //Moves the stack pointer back 4
*(int *)(*stack_pointer) = argc;
- move_stack_pointer(*stack_pointer, -4); //Moves the stack pointer back 4
+ move_stack_pointer(stack_pointer, -4); //Moves the stack pointer back 4
(*(int *)(*stack_pointer)) = 0;
}
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--
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