On 19/04/2019 10:10, Manuel Bouyer wrote: [snip] Did you see my suggestion for getting the backtrace from the lwp on the "other" cpu?
db{0}> mach cpu 1
kdb_trap: switching to cpu1
Stopped in pid 21532.1 (gcc) at netbsd:_kernel_lock+0x19c:<hang>
So cpu 1 is indeed running the LWP hodling the spin lock, and it looks
like it's itself waiting for a mutex.
Now I have to find why "mach cpu 1" hangs, and how to avoid it ...
The kdb_trap code is racey and needs to look more like the mips version. Feel free to beat me to fixing it. Nick