2017-07-20 02:03, Mark Johnston wrote:
One thing to try at this point would be to disable EARLY_AP_STARTUP in the kernel config. That is, take a configuration with which you're able to reproduce the hang during boot, and remove "options EARLY_AP_STARTUP".
Done. And it avoids the problem altogether! Thanks. Tried a reboot several times and it succeeds every time. Here is all that I had in a config file for building a kernel, i.e. I took away the 'options DDB' which also seemingly avoided the problem: include GENERIC ident NELI nooptions EARLY_AP_STARTUP
This feature has a fairly large impact on the bootup process and has had a few problems that manifested as hangs during boot. There was at least one other case where an innocuous change to the kernel configuration "fixed" the problem by introducing some second-order effect (causing kernel threads to be scheduled in a different order, for instance).
Regardless of whether the suggestion above makes a difference, it would be helpful to see verbose dmesgs from both a clean boot and a boot that hangs. If disabling EARLY_AP_STARTUP helps, then we can try adding some assertions that will cause the system to panic when the hang occurs, making it easier to see what's going on.
Hmmm. I have now saved a couple of versions of /var/run/dmesg.boot (in boot_verbose mode) when EARLY_AP_STARTUP is disabled and the boot is successful. However, I don't know how to capture such log when booting hangs, as I have no serial interface and the boot never completes. All I have is a screen photo of the last state when a hang occurs (showing ada disks successfully attached, followed immediately by the attempt to attach a da disk, which hangs). Mark _______________________________________________ freebsd-stable@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"
