Random Kernel Panic on Dreamplug (FS related)

[Mattia Rossi]

This might be part of the weird FFS issues the Dreamplug has and no-one 
knows why they're happening.

The panic occurred while running nsd-control reload (which should simply 
re-read a config file from disk). I was previously editing files without 
issues.

Result is the following:

vm_fault(0xc10a0000, d0238000, 2, 0) -> 2
Fatal kernel mode data abort: 'Permission Fault (P)'
trapframe: 0xde019898
FSR=0000000f, FAR=d0238120, spsr=20000013
r0 =d0238120, r1 =00000e60, r2 =00000000, r3 =00000000
r4 =00000120, r5 =00000000, r6 =c3f3f6c0, r7 =00001000
r8 =c443e880, r9 =00000000, r10=c3d69000, r11=de019a20
r12=d0238120, ssp=de0198e8, slr=c0d53828, pc =c0de521c

[ thread pid 21116 tid 100073 ]
Stopped at      memset+0x48:    undge   0xa0cc20f8
db>
db> bt
Tracing pid 21116 tid 100073 td 0xc3e97000
db_trace_self() at db_trace_self
          pc = 0xc0dd5418  lr = 0xc094f8a8 (db_hex2dec+0x490)
          sp = 0xde0195a0  fp = 0xde0195b8
         r10 = 0xc0f5e8c8
db_hex2dec() at db_hex2dec+0x490
          pc = 0xc094f8a8  lr = 0xc094f260 (db_command_loop+0x300)
          sp = 0xde0195c0  fp = 0xde019660
          r4 = 0x00000000  r5 = 0x00000000
          r6 = 0x00000000
db_command_loop() at db_command_loop+0x300
          pc = 0xc094f260  lr = 0xc094efb0 (db_command_loop+0x50)
          sp = 0xde019668  fp = 0xde019678
          r4 = 0xc0e2dfe4  r5 = 0xc0e4402e
          r6 = 0xc0f5e8b4  r7 = 0xc0ef62b8
          r8 = 0xc0f52754  r9 = 0xc0f52750
         r10 = 0xc3e97000
db_command_loop() at db_command_loop+0x50
          pc = 0xc094efb0  lr = 0xc09519ec (X_db_symbol_values+0x250)
          sp = 0xde019680  fp = 0xde0197a0
          r4 = 0x00000000  r5 = 0xc0f5e8c0
          r6 = 0xc0f52778
X_db_symbol_values() at X_db_symbol_values+0x250
          pc = 0xc09519ec  lr = 0xc0b37b08 (kdb_trap+0xc4)
          sp = 0xde0197a8  fp = 0xde0197c8
          r4 = 0x00000000  r5 = 0x0000000f
          r6 = 0xc0f52778  r7 = 0xc0ef62b8
kdb_trap() at kdb_trap+0xc4
          pc = 0xc0b37b08  lr = 0xc0de7c60 (data_abort_handler+0x7f8)
          sp = 0xde0197d0  fp = 0xde0197e8
          r4 = 0xde019898  r5 = 0x0000000f
          r6 = 0x600000d3  r7 = 0xd0238120
          r8 = 0x00000000  r9 = 0xc0f648d4
         r10 = 0xc3e97000
data_abort_handler() at data_abort_handler+0x7f8
          pc = 0xc0de7c60  lr = 0xc0de7a28 (data_abort_handler+0x5c0)
          sp = 0xde0197f0  fp = 0xde019890
          r4 = 0xc10a0000  r5 = 0x00000013
          r6 = 0xde019eb0  r7 = 0x00000002
data_abort_handler() at data_abort_handler+0x5c0
          pc = 0xc0de7a28  lr = 0xc0dd711c (exception_exit)
          sp = 0xde019898  fp = 0xde019a20
          r4 = 0xffffffff  r5 = 0xffff1004
          r6 = 0xc3f3f6c0  r7 = 0x00001000
          r8 = 0xc443e880  r9 = 0x00000000
         r10 = 0xc3d69000
exception_exit() at exception_exit
          pc = 0xc0dd711c  lr = 0xc0d53828 (ffs_truncate+0xaa8)
          sp = 0xde0198e8  fp = 0xde019a20
          r0 = 0xd0238120  r1 = 0x00000e60
          r2 = 0x00000000  r3 = 0x00000000
          r4 = 0x00000120  r5 = 0x00000000
          r6 = 0xc3f3f6c0  r7 = 0x00001000
          r8 = 0xc443e880  r9 = 0x00000000
         r10 = 0xc3d69000 r12 = 0xd0238120
memset() at memset+0x48
          pc = 0xc0de521c  lr = 0xc0d53828 (ffs_truncate+0xaa8)
          sp = 0xde0198e8  fp = 0xde019a20
Unwind failure (no registers changed)

The sad thing is, that with fsck broken for the dreamplug, I have to 
re-format the disk, reinstall everything and recreate the config files 
which I didn't manage to copy to a safe place beforehand :-(

Before I do that I'll leave the system in debugging mode for a few days, 
in case someone can help and needs some more information.

Cheers,

Mat