Messages in this thread | | | From | "Levin, Alexander (Sasha Levin)" <> | Subject | Re: sched: serial port lockdep warning when offlining CPUs | Date | Thu, 28 Sep 2017 11:04:29 +0000 |
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On Thu, Sep 28, 2017 at 11:38:47AM +0200, Peter Zijlstra wrote: >On Thu, Sep 28, 2017 at 02:19:46AM -0700, Sasha Levin wrote: >> Hi all, >> >> I seem to be hitting the following warning when offlining CPUs on the >> latest -next kernel: >> >> [289683102.607076] Unregister pv shared memory for cpu 8 >> [289683102.622922] select_fallback_rq: 3 callbacks suppressed > >This is because you hit a printk() from the scheduler, that's known >broken (along with the rest of printk). > >You forgot to actually include that printk() though I suspect it reads >like: > > "process %d (%s) no longer affine to cpu%d\n" > >Now that uses printk_deferred() which _should_ work lots better, but >clearly the printk() stuff went wobbly again.
Hm, so is this an actual possible lockup, or just a false positive?
>> [289683102.626292] vprintk_emit (kernel/printk/printk.c:1876) >> [289683102.626294] vprintk_default (kernel/printk/printk.c:1918) >> [289683102.626295] vprintk_func (kernel/printk/printk_safe.c:382) >> [289683102.626297] printk (kernel/printk/printk.c:1943) >> [289683102.626299] ? show_regs_print_info (kernel/printk/printk.c:1943) >> [289683102.626301] ? lock_acquire (kernel/locking/lockdep.c:4004) >> [289683102.626306] ___ratelimit (lib/ratelimit.c:52) >> [289683102.626309] __printk_ratelimit (kernel/printk/printk.c:2874) >> [289683102.626311] select_fallback_rq (kernel/sched/core.c:1525 (discriminator 1)) >> [289683102.626313] sched_cpu_dying (kernel/sched/core.c:5500 kernel/sched/core.c:5687) > >Also, could you pretty please not line wrap logs?
Sure, I had to resort to using gmail at a conference :(
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Thanks, Sasha
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