On 10/2/2013 6:15 PM, Adam D. Ruppe wrote:
Segfaults aren't necessarily bugs... though I'm not sure if a userspace handler can do much about it. But from a kernel perspective, they can be generated by page faults too, which can be successfully handled by loading the requested memory block (e.g. from a swap file) and then retrying the operation, or copying the page into a writable location and mapping that in; hardware assisted copy-on-write.
That's true, and in fact I implemented a generational GC once that relied on catching seg faults from invalid writes to keep track of which pages were 'dirty'. It did work fine, although it turned out to be too slow.
I've never tried to do this in a unix program so I don't know how much you can do, but presumably Sean's example did something along these lines, so it would be by design rather than bugs.
If that is the design, then I misunderstood it.
