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-rw-r--r--arch/arm64/kernel/stacktrace.c17
1 files changed, 8 insertions, 9 deletions
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index 4fad9787ab46..d9751a4769e7 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -44,14 +44,13 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame)
unsigned long irq_stack_ptr;
/*
- * Use raw_smp_processor_id() to avoid false-positives from
- * CONFIG_DEBUG_PREEMPT. get_wchan() calls unwind_frame() on sleeping
- * task stacks, we can be pre-empted in this case, so
- * {raw_,}smp_processor_id() may give us the wrong value. Sleeping
- * tasks can't ever be on an interrupt stack, so regardless of cpu,
- * the checks will always fail.
+ * Switching between stacks is valid when tracing current and in
+ * non-preemptible context.
*/
- irq_stack_ptr = IRQ_STACK_PTR(raw_smp_processor_id());
+ if (tsk == current && !preemptible())
+ irq_stack_ptr = IRQ_STACK_PTR(smp_processor_id());
+ else
+ irq_stack_ptr = 0;
low = frame->sp;
/* irq stacks are not THREAD_SIZE aligned */
@@ -64,8 +63,8 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame)
return -EINVAL;
frame->sp = fp + 0x10;
- frame->fp = *(unsigned long *)(fp);
- frame->pc = *(unsigned long *)(fp + 8);
+ frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp));
+ frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp + 8));
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
if (tsk && tsk->ret_stack &&