The attached change defers the initialization of the variables tsk, mm
and flags until they
are needed. As a result, the code won't crash if a kernel probe is
done with a corrupt context
and the code will be better optimized.
Signed-off-by: John David Anglin <dave.anglin@xxxxxxxx>
---
diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c
index 00c0ed3..0293588 100644
--- a/arch/parisc/mm/fault.c
+++ b/arch/parisc/mm/fault.c
@@ -171,20 +171,25 @@ void do_page_fault(struct pt_regs *regs, unsigned long code,
unsigned long address)
{
struct vm_area_struct *vma, *prev_vma;
- struct task_struct *tsk = current;
- struct mm_struct *mm = tsk->mm;
+ struct task_struct *tsk;
+ struct mm_struct *mm;
unsigned long acc_type;
int fault;
- unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
+ unsigned int flags;
- if (in_atomic() || !mm)
+ if (in_atomic())
goto no_context;
+ tsk = current;
+ mm = tsk->mm;
+ if (!mm)
+ goto no_context;
+
+ flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
if (user_mode(regs))
flags |= FAULT_FLAG_USER;
acc_type = parisc_acctyp(code, regs->iir);
-
if (acc_type & VM_WRITE)
flags |= FAULT_FLAG_WRITE;
retry:
--
John David Anglin dave.anglin@xxxxxxxx
