On 01/09/14 12:50, Russell King - ARM Linux wrote:
On Mon, Sep 01, 2014 at 12:46:06PM +0100, Sudeep Holla wrote:From: Sudeep Holla <sudeep.holla@xxxxxxx> Commit 01f8fa4f01d8("genirq: Allow forcing cpu affinity of interrupts") enabled the forced irq_set_affinity which previously refused to route an interrupt to an offline cpu. Commit ffde1de64012("irqchip: Gic: Support forced affinity setting") implements this force logic and disables the cpu online check for GIC interrupt controller. When __cpu_disable calls migrate_irqs, it disables the current cpu in cpu_online_mask and uses forced irq_set_affinity to migrate the IRQs away from the cpu but passes affinity mask with the cpu being offlined also included in it. If irq_set_affinity is called with force=true in a cpu hotplug path, the caller must ensure that the cpu being offlined is not present in the affinity mask or it may be selected as the target CPU, leading to the interrupt not being migrated. This patch fixes the issue by calling irq_set_affinity with force=false so that cpu_online_mask is checked while setting the affinity in the cpu hotplug path. Tested on TC2 hotpluging CPU0 in and out. Without this patch the system locks up as the IRQs are not migrated away from CPU0. Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx> Cc: Russell King <linux@xxxxxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Mark Rutland <mark.rutland@xxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> # 3.10.x --- arch/arm/kernel/irq.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) Hi Russell, If you or tglx has no objections to this patch, I will put it in your patch tracker.Post discussion, I have no objections - except to the above comment. Let me rewrite it in a programming language, and maybe you can spot what's wrong: if (russell_has_no_objection(patch) || tglx_has_no_objection(patch)) submit_patch_to_tracker(patch); Personally, I'd like to see tglx's ack on this first.
Understood, I will wait for ack from tglx. Regards, Sudeep -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html