The oops can be triggered in qemu using -no-hpet (but not nohpet) by
reading a couple of pages past the end of the vdso text. This
should send SIGBUS instead of OOPSing.
The bug was introduced by:
commit 7a59ed415f5b57469e22e41fc4188d5399e0b194
Author: Stefani Seibold <stefani@xxxxxxxxxxx>
Date: Mon Mar 17 23:22:09 2014 +0100
x86, vdso: Add 32 bit VDSO time support for 32 bit kernel
which is new in 3.15.
This will be fixed separately in 3.15, but that patch will not apply
to tip/x86/vdso. This is the equivalent fix for tip/x86/vdso and,
presumably, 3.16.
Cc: Stefani Seibold <stefani@xxxxxxxxxxx>
Reported-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
---
arch/x86/vdso/vma.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/x86/vdso/vma.c b/arch/x86/vdso/vma.c
index e915eae..8ad0081 100644
--- a/arch/x86/vdso/vma.c
+++ b/arch/x86/vdso/vma.c
@@ -90,6 +90,7 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr)
struct vm_area_struct *vma;
unsigned long addr;
int ret = 0;
+ static struct page *no_pages[] = {NULL};
if (calculate_addr) {
addr = vdso_addr(current->mm->start_stack,
@@ -125,7 +126,7 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr)
addr + image->size,
image->sym_end_mapping - image->size,
VM_READ,
- NULL);
+ no_pages);
if (IS_ERR(vma)) {
ret = PTR_ERR(vma);
--
1.9.0
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