On Thu, Aug 6, 2020 at 11:02 AM Nadav Har'El <n...@scylladb.com> wrote:
> The assert was there to make a rare random crash into a reliable crash. > The thing is > that symbol resolution needs to take a mutex, because in very rare cases > it might be > running in parallel to someone loading an additional shared object. This > taking of a mutex > may block the thread, and when in non-preemptable state, will cause a > crash at that > point. So the idea of the assert is to make you aware of this problem much > earlier, > before you start seeing it once a year in the field. > By the way, if this problem really bothered us, it should be possible with relatively small effort to make symbol-resolution lock-free. We actually have the list of objects protected by RCU, not a mutex (see commit 68afb68ee84769db064949839ee50bff08145c6e) so it is already possible to do most of the lookup in a lock-free manner, and we just need to replace the last remaining mutexes in the resolv_pltgot code, which might not be difficult. -- You received this message because you are subscribed to the Google Groups "OSv Development" group. To unsubscribe from this group and stop receiving emails from it, send an email to osv-dev+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/osv-dev/CANEVyjv81m6VXVi9OLsrhDYxfi2QSOc44WtiEA2PWbkKpPbkuQ%40mail.gmail.com.
