USB-related problem

[Eugene Grosbein]

On 20.11.2015 02:05, Adrian Chadd wrote:
> On 17 November 2015 at 00:15, Eugene Grosbein <eugen at grosbein.net> wrote:
>> On 17.11.2015 14:44, Adrian Chadd wrote:
>>> hiya,
>>>
>>> any updates? I caan't trigger this one myself :(
>>
>> No updates. Yesterday I've spent some time to discover if KASSERT is guilty
>> but finally found sysctl debug.kassert.kassert and it works as expected, no hangs.
>> Working backtrace in KDB would be invaluable.
>>
> 
> Yeah. When it happens, do "show registers" ? I'd like to see if the
> registers show anything useful.

Just reproduced the deadlock:

[4/17] Extracting pcre-8.37_4:  24%KDB: enter: Break to debugger
[ thread pid 14 tid 100036 ]
Stopped at      kdb_enter+0x4c: lui     at,0x8044
db> show registers
at          0x80440000  cc_cpu+0xa0c0
v0                0x1e  _DYNAMIC_LINKING+0x1d
v1                0x1e  _DYNAMIC_LINKING+0x1d
a0                   0
a1                 0x4  _DYNAMIC_LINKING+0x3
a2          0x803756b8
a3               0x12f  _DYNAMIC_LINKING+0x12e
t0          0x8046afec
t1                   0
t2                   0
t3                   0
t4                   0
t5                   0
t6                   0
t7                   0
s0          0x80362bb8  mips_event_codes_size+0x7638
s1          0x8058cc00
s2             0x40000
s3          0x8058cc00
s4          0x803ec4dc  uart_ipend_desc
s5                   0
s6          0x803ec500  uart_receive_desc
s7          0x8058cc88
t8             0x18006
t9            0x7e2290
k0          0x805d4390
k1          0x8031a2a4  spinlock_exit+0x1c
gp          0x80421c80  _gp
sp          0xc3adb8e8
s8          0x803ec4b8  uart_flush_desc
ra          0x801be69c  kdb_enter+0x40
sr              0xec02  _DYNAMIC_LINKING+0xec01
lo                 0x1  _DYNAMIC_LINKING
hi              0x5135  _DYNAMIC_LINKING+0x5134
bad         0xc083d950
cs          0x4000c024
pc          0x801be6a8  kdb_enter+0x4c
kdb_enter+0x4c: lui     at,0x8044
db>