Messages in this thread | | | Date | Wed, 14 Sep 2016 18:15:41 -0400 | From | Waiman Long <> | Subject | Re: [PATCH] random: Fix kernel panic due to system_wq use before init |
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On 09/14/2016 05:06 PM, Linus Torvalds wrote: > On Wed, Sep 14, 2016 at 12:34 PM, Waiman Long<waiman.long@hpe.com> wrote: >> I can try, but the 16-socket system that I have at the moment takes a long >> time (more than an hour) for one shutdown-reboot cycle. It may not be really >> more interrupts in 4.8, it may be that the random driver just somehow run >> very slow on my test machine as it seems to have a major rewrite in the 4.8 >> cycle. > Looking at the random driver updates since 4.7, the only thing I see > is that .crng_fast_load() for the chacha20 randomness. And that should > trigger only until it's been initialized, so the cost looks like it > should be limited. > > Is there some fundamental reason you think it's the random driver? > Other than the oops? Because I'd be more inclined to suspect just some > apic issue or something, where an actual interrupt line ends up > screaming or whatever. Is this UV? There's also the CPU hotplug state > machine changes etc.
Yes, it is because of the oops that I suspect the random driver may be the cause.
> But a few rounds of bisecting should hopefully cut down on the > suspects a lot. A *full* bisect might be 16-17 rounds, but if you can > do just four or five rounds of bisection, that should still cut it > down from 14k commits to "only" several hundred.. > > Linus
Yes, I will do a few rounds to see if we can isolate the problem. In the mean time, I will also reconfigure the system with less sockets to see if it is reproduced in a smaller configuration.
Cheers, Longman
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