Almost certainly the latter. Is the disk interrupt shared with any
other interrupts, that are marked IRQF_NODELAY? The -rt patch doesn't
seem to handle mixing the two well.
Oh, and just to be sure: you do have CONFIG_PREEMPT_RT turned on, and
not just CONFIG_PREEMPT, right? The non-preempt-rt versions in the -rt
patch don't look like they disable interrupts, though I may just be
getting lost in a sea of underscores and ifdefs.
-Scott
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