i386: allow debuggers to access the vsyscall page with compat vDSO

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/arch/i386/kernel/sysenter.c b/arch/i386/kernel/sysenter.c
index ff4ee6f3326b..6deb159d08e0 100644
--- a/arch/i386/kernel/sysenter.c
+++ b/arch/i386/kernel/sysenter.c
@@ -336,7 +336,9 @@ struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
 
 int in_gate_area(struct task_struct *task, unsigned long addr)
 {
-        return 0;
+        const struct vm_area_struct *vma = get_gate_vma(task);
+
+        return vma && addr >= vma->vm_start && addr < vma->vm_end;
 }
 
 int in_gate_area_no_task(unsigned long addr)