Re: [uml-user] UML not shutting down due to "task killall5 blocked for more than 120 seconds"

[Riccardo M. <ric...@gm...>]

Hi Richard,

On Wed, May 9, 2012 at 12:06 PM, richard -rw- weinberger
<ric...@gm...> wrote:
>> we're having issues with a UML machine that refuses to shut down: the
>> halt sequence commences and then we get the following kernel error
>> message and backtrace:
>>
>>    Asking all remaining processes to terminate...
>>    INFO: task killall5:5269 blocked for more than 120 seconds.
>>    [ 1080.320000] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
>> disables this message.
>>    [ 1080.320000] killall5        D 00000000405070c3     0  5269
>> 5266 0x00000000
>>    [ 1080.320000] 93d84c08 9354d288 9354ce38 6063e550 9200bc28
>> 6001a7f3 93d84780 92008000
>>    [ 1080.320000]        92008000 93d84780 9200bc88 604345ad 9200bc48
>> 9354ce00 9200bc88 92008000
>>    [ 1080.320000]        00000001 93d84780 93588060 00000001
>> ffffffffffffffff 00000000 9200bce8 604357cd
>>    [ 1080.320000] Call Trace:
>>    [ 1080.320000] 9200bc00:  [<6001a7f3>] _switch_to+0x5e/0xae
>>    [ 1080.320000] 9200bc30:  [<604345ad>] schedule+0x240/0x27a
>>    [ 1080.320000] 9200bc90:  [<604357cd>] rwsem_down_failed_common+0xb8/0xd8
>>    [ 1080.320000] 9200bcf0:  [<60435814>] rwsem_down_read_failed+0x12/0x14
>>    [ 1080.320000] 9200bd00:  [<6002ecec>] call_rwsem_down_read_failed+0x14/0x24
>>    [ 1080.320000] 9200bd48:  [<60434fc2>] down_read+0x11/0x13
>>    [ 1080.320000] 9200bd58:  [<6007a6ec>] access_process_vm+0x45/0x147
>>    [ 1080.320000] 9200bdc8:  [<600cdd13>] proc_pid_cmdline+0x65/0xf9
>>    [ 1080.320000] 9200be18:  [<600cf298>] proc_info_read+0x68/0xcb
>>    [ 1080.320000] 9200be68:  [<6008f2c7>] vfs_read+0xa7/0x155
>>    [ 1080.320000] 9200bea8:  [<6008f42e>] sys_read+0x45/0x6c
>>    [ 1080.320000] 9200bee8:  [<6001cd9c>] handle_syscall+0x58/0x70
>>    [ 1080.320000] 9200bf08:  [<6002c00f>] userspace+0x2d4/0x381
>>    [ 1080.320000] 9200bfc8:  [<6001a6f3>] fork_handler+0x62/0x69
>>    [ 1080.320000]
>>
>> The error repeats every 120 seconds, and the machine never shuts down.
>
> Can you please try a recent kernel?
> Maybe you need this commit:
> 3a3679078aed2c451ebc32836bbd3b8219a65e01 (um: Use RWSEM_GENERIC_SPINLOCK on x86)
>

We're trying 3.2.16 right now (also from devloop.org.uk); it might
take some time before we are able to confirm or disprove, since the
bug does not occur deterministically but only on a certain percentage
of the runs.

Thanks,
Riccardo