---

yaml
---
r: 180338
b: refs/heads/master
c: 944a343
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 1dca56f13899b9e256f56198026019835aaf9a3a
+refs/heads/master: 944a3438615da65f11e2559840404a2cac5f65ea

trunk/arch/sh/kernel/dwarf.c

@@ -540,6 +540,8 @@ void dwarf_free_frame(struct dwarf_frame *frame)
 	mempool_free(frame, dwarf_frame_pool);
 }
 
+extern void ret_from_irq(void);
+
 /**
  *	dwarf_unwind_stack - unwind the stack
  *
@@ -678,6 +680,24 @@ struct dwarf_frame * dwarf_unwind_stack(unsigned long pc,
 	addr = frame->cfa + reg->addr;
 	frame->return_addr = __raw_readl(addr);
 
+	/*
+	 * Ah, the joys of unwinding through interrupts.
+	 *
+	 * Interrupts are tricky - the DWARF info needs to be _really_
+	 * accurate and unfortunately I'm seeing a lot of bogus DWARF
+	 * info. For example, I've seen interrupts occur in epilogues
+	 * just after the frame pointer (r14) had been restored. The
+	 * problem was that the DWARF info claimed that the CFA could be
+	 * reached by using the value of the frame pointer before it was
+	 * restored.
+	 *
+	 * So until the compiler can be trusted to produce reliable
+	 * DWARF info when it really matters, let's stop unwinding once
+	 * we've calculated the function that was interrupted.
+	 */
+	if (prev && prev->pc == (unsigned long)ret_from_irq)
+		frame->return_addr = 0;
+
 	return frame;
 
 bail: