From: Thomas Gleixner <tglx@xxxxxxxxxxxxx> commit 1d21f2af8571c6a6a44e7c1911780614847b0253 upstream. The function might sleep, so it cannot be called from interrupt context. Not even with care. Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Marc Zyngier <marc.zyngier@xxxxxxx> Link: https://lkml.kernel.org/r/20190628111440.189241552@xxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- kernel/irq/manage.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -96,7 +96,8 @@ EXPORT_SYMBOL(synchronize_hardirq); * to complete before returning. If you use this function while * holding a resource the IRQ handler may need you will deadlock. * - * This function may be called - with care - from IRQ context. + * Can only be called from preemptible code as it might sleep when + * an interrupt thread is associated to @irq. */ void synchronize_irq(unsigned int irq) {
