sparc64: Fix hardirq tracing in trap return path. (28a1f533) · Commits · 戴 / test

We can overflow the hardirq stack if we set the %pil here so early, just let the normal control flow do it. This is fine as we are allowed to do the actual IRQ enable at any point after we call trace_hardirqs_on. Signed-off-by:

David S. Miller <davem@davemloft.net>

arch/sparc/kernel/rtrap_64.S

+11 −1

Original line number	Diff line number	Diff line
		@@ -130,7 +130,17 @@ rtrap_xcall:
		nop
		call trace_hardirqs_on
		nop
		wrpr %l4, %pil
		/* Do not actually set the %pil here. We will do that
		* below after we clear PSTATE_IE in the %pstate register.
		* If we re-enable interrupts here, we can recurse down
		* the hardirq stack potentially endlessly, causing a
		* stack overflow.
		*
		* It is tempting to put this test and trace_hardirqs_on
		* call at the 'rt_continue' label, but that will not work
		* as that path hits unconditionally and we do not want to
		* execute this in NMI return paths, for example.
		*/
		#endif
		rtrap_no_irq_enable:
		andcc %l1, TSTATE_PRIV, %l3

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