Messages in this thread | | | Date | Tue, 31 Oct 2017 17:30:58 +0100 | From | Peter Zijlstra <> | Subject | Re: possible deadlock in lru_add_drain_all |
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On Tue, Oct 31, 2017 at 04:45:46PM +0100, Michal Hocko wrote: > Anyway, this lock dependecy is subtle as hell and I am worried that we > might have way too many of those. We have so many callers of > get_online_cpus that dependecies like this are just waiting to blow up.
Yes, the filesystem locks inside hotplug thing is totally annoying. I've got a few other splats that contain a similar theme and I've no real clue what to do about.
See for instance this one:
https://lkml.kernel.org/r/20171027151137.GC3165@worktop.lehotels.local
splice from devtmpfs is another common theme and links it do the pipe->mutex, which then makes another other splice op invert against that hotplug crap :/
I'm sure I've suggested simply creating possible_cpus devtmpfs files up front to get around this... maybe we should just do that.
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