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 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.
Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
---
I'll resend the tip/x86/vdso version of this patch once this one gets
picked up.
arch/x86/vdso/vdso32-setup.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c
index 0034898..3adf2e6 100644
--- a/arch/x86/vdso/vdso32-setup.c
+++ b/arch/x86/vdso/vdso32-setup.c
@@ -154,6 +154,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
unsigned long addr;
int ret = 0;
struct vm_area_struct *vma;
+ static struct page *no_pages[] = {NULL};
#ifdef CONFIG_X86_X32_ABI
if (test_thread_flag(TIF_X32))
@@ -192,7 +193,7 @@ 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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