> I attempted to investigate this further, while very reproducible, it's > difficult get a good trace. Once the bug is fully engaged, it becomes > impossible to break into ddb, the system is completely unresponsive. > > However, triggering ddb a few seconds before and stepping through > instructions is possible. The breakpoint chain seems to follow below: > > ffs_read > VOP_READ > uvn_io > uvn_get > uvm_fault_lower_io > uvm_fault_lower > uvm_fault > upageflttrap > userret > > followed by an infinite stream of: > > kernel: double fault trap, code=0 > > with the ddb pager triggered, but unable to break out of. > > I hope this information is helpful to someone. > > Regards > Lloyd
Hi Lloyd, Thank you for getting that! I see in ffs_read, there are some diagnostic lines, seems like I could rebuild the kernel with that. I am hoping I have time to enable diagnostics and try this in a VM. Might be easier to capture a good stacktrace? Getting pretty close to a release window and it'd be nice to have this fixed. -Henrich
