On Fri, Oct 14, 2022 at 12:00:31PM -0700, Bhatnagar, Rishabh wrote: > > On 10/9/22 10:50 AM, Bhatnagar, Rishabh wrote: > > > > On 10/6/22 8:07 PM, Herrenschmidt, Benjamin wrote: > > > (putting my @amazon.com hat on) > > > > > > On Sun, 2022-10-02 at 17:30 +0200, Greg KH wrote: > > > > > > > > > > On Thu, Sep 29, 2022 at 09:06:45PM +0000, Rishabh Bhatnagar wrote: > > > > > This patch series backports a bunch of patches related IRQ handling > > > > > with respect to freeing the irq line while IRQ is in flight at CPU > > > > > or at the hardware level. > > > > > Recently we saw this issue in serial 8250 driver where the IRQ was > > > > > being > > > > > freed while the irq was in flight or not yet delivered to the CPU. > > > > > As a > > > > > result the irqchip was going into a wedged state and IRQ was not > > > > > getting > > > > > delivered to the cpu. These patches helped fixed the issue in 4.14 > > > > > kernel. > > > > Why is the serial driver freeing an irq while the system is running? > > > > Ah, this could happen on a tty hangup, right? > > > Right. Rishabh answered that separately. > > > > > > > > Let us know if more patches need backporting. > > > > What hardware platform were these patches tested on to verify they > > > > work properly? And why can't they move to 4.19 or newer if they > > > > really need this fix? What's preventing that? > > > > > > > > As Amazon doesn't seem to be testing 4.14.y -rc releases, I find it > > > > odd that you all did this backport. Is this a kernel that you all > > > > care about? > > > These were tested on a collection of EC2 instances, virtual and metal I > > > believe (Rishabh, please confirm). > > Yes these patches were tested on multiple virt/metal EC2 instances. > > > > > > Amazon Linux 2 runs 4.14 or 5.10. Unfortunately we still have to > > > support customers running the former. > > > > > > We'll be including these patches in our releases, we thought it would > > > be nice to have them in -stable as well for the sake of whoever else > > > might be still using this kernel. No huge deal if they don't. > > > > > > As for testing -rc's, yes, we need to get better at that (and publish > > > what we test). Point taken :-) > > > > > > Cheers, > > > Ben. > > > > Hi Greg > > Let us know if you think it would be beneficial to take these backports for > 4.14 stable. Give me some time after -rc1 is out to review this then as we are swamped right now. > We can drop this patch set otherwise. You can do whatever you want with your tree :) thanks, greg k-h
