On Fri, Aug 24, 2018 at 10:01:35AM +0200, Thomas Gleixner wrote: > On Fri, 24 Aug 2018, Heiner Kallweit wrote: > > On 24.08.2018 06:12, Frederic Weisbecker wrote: > > > On Thu, Aug 16, 2018 at 08:13:03AM +0200, Heiner Kallweit wrote: > > >> Recently I started to get warning "NOHZ: local_softirq_pending 202" and > > >> I think it's related to mentioned commit (didn't bisect it yet). > > >> See log from suspending. > > >> > > >> I have no reason to think the fix is wrong, it may just have revealed > > >> another issue which existed before and was hidden by the bug. > > >> > > >> Rgds, Heiner > > >> > > >> [ 75.073353] random: crng init done > > >> [ 75.073402] random: 7 urandom warning(s) missed due to ratelimiting > > >> [ 78.619564] PM: suspend entry (deep) > > >> [ 78.619675] PM: Syncing filesystems ... done. > > >> [ 78.653684] Freezing user space processes ... (elapsed 0.002 seconds) > > >> done. > > >> [ 78.656094] OOM killer disabled. > > >> [ 78.656113] Freezing remaining freezable tasks ... (elapsed 0.001 > > >> seconds) done. > > >> [ 78.658177] Suspending console(s) (use no_console_suspend to debug) > > >> [ 78.663066] nuvoton-cir 00:07: disabled > > >> [ 78.671817] sd 0:0:0:0: [sda] Synchronizing SCSI cache > > >> [ 78.672210] sd 0:0:0:0: [sda] Stopping disk > > >> [ 78.786651] ACPI: Preparing to enter system sleep state S3 > > >> [ 78.789613] PM: Saving platform NVS memory > > >> [ 78.789759] Disabling non-boot CPUs ... > > >> [ 78.805154] NOHZ: local_softirq_pending 202 > > >> [ 78.805182] NOHZ: local_softirq_pending 202 > > >> [ 78.807102] smpboot: CPU 1 is now offline > > > > > > I've tried to reproduce with suspend on disk but got unsuccessful. > > > > > > A small question as I see someone is having a similar issue with a stable > > > release only. On which kernel did you trigger that: upstream or stable? > > > > > > I'll continue investigating. > > > > > > Thanks. > > > > > Affected is recent linux-next, after the commit mentioned in the subject. > > I can work around the warning (not sure whether it's a proper fix), > > see here: > > https://lkml.org/lkml/2018/8/18/272 > > Can you try the one I posted in this thread: > > > https://lkml.kernel.org/r/alpine.deb.2.21.1808240851420.1...@nanos.tec.linutronix.de > > Also below for reference. > > Thanks, > > tglx > > 8<---------------- > diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c > index 5b33e2f5c0ed..6aab9d54a331 100644 > --- a/kernel/time/tick-sched.c > +++ b/kernel/time/tick-sched.c > @@ -888,7 +888,7 @@ static bool can_stop_idle_tick(int cpu, struct tick_sched > *ts) > if (unlikely(local_softirq_pending() && cpu_online(cpu))) { > static int ratelimit; > > - if (ratelimit < 10 && > + if (ratelimit < 10 && !in_softirq() && > (local_softirq_pending() & SOFTIRQ_STOP_IDLE_MASK)) { > pr_warn("NOHZ: local_softirq_pending %02x\n", > (unsigned int) local_softirq_pending());
I fear it may not work in his case because it happens in -next and we don't stop the idle tick from IRQ tail anymore. So we shouldn't be interrupting a softirq in this path. Still it's worth trying, I may well be missing something. Thanks.
