| Message ID | 20180210142020.30212-1-marc.zyngier@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 10/02/18 14:20, Marc Zyngier wrote: > Calling request_irq() followed by disable_irq() is usually a bad idea, > specially if the interrupt can be pending, and you're not yet in a > position to handle it. > > This is exactly what happens on my kevin system when rebooting in a > second kernel using kexec: Some interrupt is left pending from > the previous kernel, and we take it too early, before disable_irq() > could do anything. > > A better way of ensuring safety is to set the IRQ_NOAUTOEN flag > on the irq before requesting it. > > Cc: stable@vger.kernel.org > Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> For the record, I've posted a (much) improved version of this as part of a series here[1]. Thanks, M. [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2018-February/560703.html
diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c index 19128b4dea54..72554f404b7e 100644 --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c @@ -32,6 +32,7 @@ #include <linux/of_device.h> #include <linux/pm_runtime.h> #include <linux/component.h> +#include <linux/irq.h> #include <linux/reset.h> #include <linux/delay.h> @@ -1569,14 +1570,12 @@ static int vop_bind(struct device *dev, struct device *master, void *data) mutex_init(&vop->vsync_mutex); + irq_set_status_flags(vop->irq, IRQ_NOAUTOEN); ret = devm_request_irq(dev, vop->irq, vop_isr, IRQF_SHARED, dev_name(dev), vop); if (ret) return ret; - /* IRQ is initially disabled; it gets enabled in power_on */ - disable_irq(vop->irq); - ret = vop_create_crtc(vop); if (ret) goto err_enable_irq;
Calling request_irq() followed by disable_irq() is usually a bad idea, specially if the interrupt can be pending, and you're not yet in a position to handle it. This is exactly what happens on my kevin system when rebooting in a second kernel using kexec: Some interrupt is left pending from the previous kernel, and we take it too early, before disable_irq() could do anything. A better way of ensuring safety is to set the IRQ_NOAUTOEN flag on the irq before requesting it. Cc: stable@vger.kernel.org Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> --- drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)