Can crash be caused by read only root partition?

Hello All.

This is my first post here. I'm using FreeBSD for quite a long time but I'm still amateur. Currently I'm using it on a home machine to handle NFS mainly.

Yesterday I have installed 10.3-R. Configured all as usual with minimal kernel (removed unnecessary drivers, debugging, tracing and INET6). After all config has been completed I set root partition as read only (var, tmp, home are read-write on separate partitions).

After a day I was trying to remount / rw with command 'mount -u -w /' but it failed. System accepted command but it did not cause any effect (mount was still showing / as ro). After three tries system crashed suddenly. No panic, no logs, no dump. Hard, immediate restart. As this issue is hard to replicate I didn't try to run generic kernel. No compiler flags were used during kernel build and usb, sound and nic are loaded as modules.

Before it I was using 10.2-R with the very same kernel config file (same hardware, too) and i didn't experience it for more than half year.

Please share what in your opinion could be the problem here. How to troubleshoot?
 
Please share what in your opinion could be the problem here. How to troubleshoot?
The only thing that comes to mind is that reroot support was added to 10.3:
10.3 Release Notes said:
•The initial implementation of reroot support has has been added to the reboot(8) utility, allowing the root file system to be mounted from a temporary source file system without requiring a full system reboot.
It might be some interaction with that code. I'd suggest asking on freebsd-stable@ as you're more likely to catch the attention of a developer there.
 
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