on 2014/3/6 23:35, Paul Gortmaker wrote:
> On 14-03-06 02:19 AM, Liu hua wrote:
>> As sysctl_hung_task_timeout_sec is unsigned long, when this value is
>> larger then LONG_MAX, the function schedule_timeout_interruptible in
>> watchdog will return immediately without sleep :
>>
>> for example (in x86_64 platform):
>>
>> linux# echo 0xFFFFFFFFFFFFFFFF > /proc/sys/kernel/hung_task_timeout_secs
>>
>> [ 66.798350] schedule_timeout: wrong timeout value ffffffffffffff06
>> [ 66.800064] schedule_timeout: wrong timeout value ffffffffffffff06
>> [ 66.801774] schedule_timeout: wrong timeout value ffffffffffffff06
>> [ 66.803488] schedule_timeout: wrong timeout value ffffffffffffff06
>> [ 66.805225] schedule_timeout: wrong timeout value ffffffffffffff06
>>
>> The screen was filled with "schedule_timeout: wrong timeout value
>> ffffffffffffff06" and the system stalled.
>>
>> So I do some check and correction in timeout_jiffies, to let the function
>> schedule_timeout_interruptible allways get the valid parameter.
>>
>> Signed-off-by: Liu Hua <sdu....@huawei.com>
>> ---
>> kernel/hung_task.c | 11 ++++++++++-
>> 1 file changed, 10 insertions(+), 1 deletion(-)
>>
>> diff --git a/kernel/hung_task.c b/kernel/hung_task.c
>> index 06bb141..ef96650 100644
>> --- a/kernel/hung_task.c
>> +++ b/kernel/hung_task.c
>> @@ -186,7 +186,16 @@ static void check_hung_uninterruptible_tasks(unsigned
>> long timeout)
>> static unsigned long timeout_jiffies(unsigned long timeout)
>> {
>> /* timeout of 0 will disable the watchdog */
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
> You are breaking the above functionality/feature by declaring
> zero invalid.
>
> Paul.
> --
>
Actually the patch will disable the watchdog if the timeout is illegal(except
0) for
schedule_timeout_interruptible.
I will make a new patch that disables the watchdog when the timeout is 0 or
above
LONG_MAX without printing errors ?
What do you think?
Liu Hua
>> - return timeout ? timeout * HZ : MAX_SCHEDULE_TIMEOUT;
>> + if ((timeout == 0) || (timeout > MAX_SCHEDULE_TIMEOUT)) {
>> + pr_err("%s : wrong timeout value %lx\n",
>> + __func__, timeout);
>> + pr_err("Timeout value is set to MAX_SCHEDULE_TIMEOUT(%lx)
>> now.\n",
>> + MAX_SCHEDULE_TIMEOUT);
>> + return MAX_SCHEDULE_TIMEOUT;
>> + }
>> +
>> + return (timeout * HZ) < MAX_SCHEDULE_TIMEOUT ?
>> + timeout * HZ : MAX_SCHEDULE_TIMEOUT;
>> }
>>
>> /*
>>
>
> .
>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
