netbsd-8 sparc panic under pmap_pmap_pool_ctor

[Paul Ripke <stix%stix.id.au@localhost>]

So I've been stressing my poor little sparcserver 5 with 32MiB RAM
by building cmake from pkgsrc. So far, I've seen 3 panics with the
same backtrace. Reading the disassembly, the fault pc in
pmap_pmap_pool_ctor seems to map to a swap between a kpreempt_disable
and kpreempt_enable pair, just after the call to VA2PA. This appears
to be the expansion of setpgt4m.

There's no core dump - can you even dump over NFS?

Does this ring a bell with anybody?

The trace is:

cpu0: data fault: pc=0xf0029a44 addr=0x0 sfsr=0x3a6<PERR=0x0,LVL=0x3,AT=0x5,FT=0x1,FAV,OW>
panic: kernel fault                                                      
cpu0: Begin traceback...                                                   
0x0(0xf02ac178, 0xf34118a0, 0xf0348800, 0xf0349400, 0xf0349608, 0x104) at netbsd:printf+0x88
printf(0xf02ac178, 0x0, 0xf0029a44, 0x0, 0xf34118c0, 0xf032a400) at netbsd:mem_access_fault4m+0x220
mem_access_fault4m(0x9, 0x3a6, 0x0, 0xf3411960, 0x40, 0xf0959ce0) at netbsd:memfault_sun4m+0xe8
memfault_sun4m(0x0, 0x1, 0x1, 0xf0331380, 0xf033137c, 0x0) at netbsd:pmap_pmap_pool_ctor+0x84
pmap_pmap_pool_ctor(0x0, 0xf0863090, 0x0, 0x3c0, 0x4, 0x0) at netbsd:pool_cache_get_slow+0x164
pool_cache_get_slow(0xf0331040, 0xf0863090, 0xf3411ad4, 0x0, 0x1, 0xf0330ec0) at netbsd:pool_cache_get_paddr+0xe0
pool_cache_get_paddr(0xf0330ec0, 0x1, 0x0, 0xf08c1b08, 0xf0002000, 0x0) at netbsd:pmap_create+0x10
pmap_create(0xf08c1b14, 0x3, 0x0, 0xf017a79c, 0x1, 0xf08c1bd8) at netbsd:uvmspace_init+0x5c
uvmspace_init(0xf08c1b08, 0x0, 0x1000, 0xf0000000, 0x1, 0x0) at netbsd:uvmspace_alloc+0x2c
uvmspace_alloc(0xf08c1b08, 0xf0000000, 0x1, 0xf3411c84, 0x0, 0xf08c1b08) at netbsd:uvmspace_exec+0x34
uvmspace_exec(0xf0959ce0, 0x1000, 0xf0000000, 0x1, 0xf088c9d8, 0xf08c1e68) at netbsd:execve_runproc+0x3a8
execve_runproc(0xf0959ce0, 0xf3411d60, 0x0, 0x0, 0x480, 0xf3411d60) at netbsd:execve1+0x34
execve1(0xf0959ce0, 0xedb41a8c, 0xedb419cc, 0xedb41a04, 0xf01982d8, 0x8722f0) at netbsd:syscall+0x248
syscall(0xc3b, 0xf3411fb0, 0xedceffa0, 0x3b, 0x4e, 0xf0959ce0) at netbsd:memfault_sun4m+0x3f4
cpu0: End traceback...

Kernel is:
NetBSD orac 8.1_RC1 NetBSD 8.1_RC1 (ORAC) #8: Fri May 24 21:14:56 AEST 2019  stix@slave:/home/netbsd/netbsd-8/obj.sparc/home/netbsd/netbsd-8/src/sys/arch/sparc/compile/ORAC sparc

-- 
Paul Ripke
"Great minds discuss ideas, average minds discuss events, small minds
 discuss people."
-- Disputed: Often attributed to Eleanor Roosevelt. 1948.