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Diffstat (limited to 'arch/s390/kernel/process.c')
-rw-r--r--arch/s390/kernel/process.c26
1 files changed, 18 insertions, 8 deletions
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
index 63873aa6693f..b0afec673f77 100644
--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -184,20 +184,30 @@ unsigned long get_wchan(struct task_struct *p)
if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
return 0;
+
+ if (!try_get_task_stack(p))
+ return 0;
+
low = task_stack_page(p);
high = (struct stack_frame *) task_pt_regs(p);
sf = (struct stack_frame *) p->thread.ksp;
- if (sf <= low || sf > high)
- return 0;
+ if (sf <= low || sf > high) {
+ return_address = 0;
+ goto out;
+ }
for (count = 0; count < 16; count++) {
- sf = (struct stack_frame *) sf->back_chain;
- if (sf <= low || sf > high)
- return 0;
- return_address = sf->gprs[8];
+ sf = (struct stack_frame *)READ_ONCE_NOCHECK(sf->back_chain);
+ if (sf <= low || sf > high) {
+ return_address = 0;
+ goto out;
+ }
+ return_address = READ_ONCE_NOCHECK(sf->gprs[8]);
if (!in_sched_functions(return_address))
- return return_address;
+ goto out;
}
- return 0;
+out:
+ put_task_stack(p);
+ return return_address;
}
unsigned long arch_align_stack(unsigned long sp)