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    SubjectRe: "BUG: Invalid wait context" in invalidate_batched_entropy
    On 2022-01-27 23:26:32 [+0100], Jason A. Donenfeld wrote:
    > Hi Jonathan,
    Hi Jason,

    > Thanks for the report. I'll try to reproduce this and see what's going on.
    >
    > I'm emailing back right away, though, so that I can CC in Andy
    > Lutomirski, who I know has been sitting on a stack of patches that fix
    > up (actually, remove) the locking, so this might be one path to fixing
    > this.

    This report is due to CONFIG_PROVE_LOCKING=y _and_
    CONFIG_PROVE_RAW_LOCK_NESTING=y. It reports a nesting problem
    (raw_spinlock_t -> spinlock_t lock ordering) which becomes a real
    problem on PREEMPT_RT.

    I've been testing my old series on top of 5.17-rc1. With blake2 the
    numbers lowered a little. I'm gettin 3-6us on average and 16-26us
    worstcase and with NUMA it still goes up to 40-50us.
    If you still object the previous approach and neither tglx/peterz
    disagree we could try making the lock raw_spinlock_t and add a mutex_t
    around the userspace interface to lower the lock contention. But even
    then we need to find a way to move the crng init part (crng_fast_load())
    out of the hard-IRQ.

    > Thanks,
    > Jason

    Sebastian

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