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-rw-r--r--arch/s390/kernel/process.c14
1 files changed, 11 insertions, 3 deletions
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
index 2ff90a1a1056..008c74526fd3 100644
--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -58,10 +58,18 @@ asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
*/
unsigned long thread_saved_pc(struct task_struct *tsk)
{
- struct stack_frame *sf;
+ struct stack_frame *sf, *low, *high;
- sf = (struct stack_frame *) tsk->thread.ksp;
- sf = (struct stack_frame *) sf->back_chain;
+ if (!tsk || !task_stack_page(tsk))
+ return 0;
+ low = task_stack_page(tsk);
+ high = (struct stack_frame *) task_pt_regs(tsk);
+ sf = (struct stack_frame *) (tsk->thread.ksp & PSW_ADDR_INSN);
+ if (sf <= low || sf > high)
+ return 0;
+ sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
+ if (sf <= low || sf > high)
+ return 0;
return sf->gprs[8];
}