TARGET_ARCH=powerpc64 jump from head -r326192 to -r327075: g_event crashes with "instruction storage interrupt"

[Mark Millard]

[Note: I experiment with using clang as the build and
system compiler for TARGET_ARCH=powerpc64 .]

I attempted to update a old so-called PowerMac "Quad Core"
from head -r326192 to -r328075, noting special instructions
that have been published. (This was a non-debug kernel
build.)

Unfortunately around the:

. . .
cd0: 66.700MB/s transfers (UDMA4, ATPI 12bytes, PIO 65534bytes)
cd0: Attempt
Trying to mount from ufs:/dev/ufs/FBSDG5Lrootfs [rw,noatime]. . .

There ends up being a repeatable kernel trap:
(transcribed from pictures, but with notes added)

fatal kernel trap:
(NOTE: The above can be the line before the "Trying to mount" line,
after the "cd0: Attempt" line.)

exception       = 0x400 (instruction storage interrupt)
virtual address = 0x3c4c009438427518
srr0            = 0x3c4c009438427518
srr1            = 0x9000000040009032
lr              = 0x14234e8
curthread       = 0x3d52a80
  pid = 13, comm = g_event

[ thread pid 13 tid 100019 ]
Stopped at 0x3c4c009438427518

It reports:

Tracing command geom pid 13 tid 100019 td 0x3d52a80 (CPU 0)
0xC0000000032966b0: at g_new_provider_event+0x144
0xC0000000032966f0: at g_run_events+0x530
0xC000000003296830: at g_event_procbody+0x94
0xC000000003296860: at fork_exit+0xd8
0xC0000000032968f0: at fork_trampoline+0x18
0xC000000003296920: at blocked_loop+0x38

These details do not vary between attempts.

From what I gather the code jumped to 0x3c4c009438427518
but that is not from an executable page for the context
at the time.

On the -r326192 powerpc system /dev/ufs/FBSDG5Lrootfs
mounts just fine.


===
Mark Millard
markmi at dsl-only.net