The access should fail, but it shouldn't oops.
Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
---
The oops can be triggered in qemu using -no-hpet (but not nohpet) by
running a 32-bit program and reading a couple of pages before the vdso.
This will conflict with tip/x86/vdso. Sorry.
arch/x86/vdso/vdso32-setup.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c
index 0034898..33426da 100644
--- a/arch/x86/vdso/vdso32-setup.c
+++ b/arch/x86/vdso/vdso32-setup.c
@@ -147,6 +147,8 @@ int __init sysenter_setup(void)
return 0;
}
+static struct page *no_pages[] = {NULL};
+
/* Setup a VMA at program startup for the vsyscall page */
int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
{
@@ -192,7 +194,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
addr - VDSO_OFFSET(VDSO_PREV_PAGES),
VDSO_OFFSET(VDSO_PREV_PAGES),
VM_READ,
- NULL);
+ no_pages);
if (IS_ERR(vma)) {
ret = PTR_ERR(vma);
--
1.9.0
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