于 2014/3/24 4:50, Satoru Takeuchi 写道:
> At Sun, 23 Mar 2014 15:54:04 +0800,
> Liu Hua wrote:
>>
>> As sysctl_hung_task_timeout_sec is unsigned long, when this value is
>> larger then LONG_MAX/HZ, the function schedule_timeout_interruptible in
>> watchdog will return immediately without sleep and with print :
>>
>> [  205.452934] schedule_timeout: wrong timeout value ffffffffffffff83
>>
>> and then the funtion watchdog will call schedule_timeout_interruptible again
>> and again. The screen will be filled with
>>      "schedule_timeout: wrong timeout value ffffffffffffff83"
>>
>> This patch does some check and correction in timeout_jiffies, to let the
>> function schedule_timeout_interruptible allways get the valid parameter.
>>
>> Cc: <sta...@vger.kernel.org>
>> Signed-off-by: Liu Hua <sdu....@huawei.com>
>> ---
>>  kernel/hung_task.c | 8 ++++++--
>>  1 file changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/kernel/hung_task.c b/kernel/hung_task.c
>> index 6df6149..f992286 100644
>> --- a/kernel/hung_task.c
>> +++ b/kernel/hung_task.c
>> @@ -174,8 +174,12 @@ static void check_hung_uninterruptible_tasks(unsigned 
>> long timeout)
>>  
>>  static unsigned long timeout_jiffies(unsigned long timeout)
>>  {
>> -    /* timeout of 0 will disable the watchdog */
>> -    return timeout ? timeout * HZ : MAX_SCHEDULE_TIMEOUT;
>> +    /* timeout of 0 or >= LONG_MAX/HZ will disable the watchdog */
>> +    if ((timeout == 0) || (timeout > MAX_SCHEDULE_TIMEOUT))
> 
> You should check whether sysctl_hung_task_timeout_sec > 
> MAX_SCHEDULE_TIMEOUT/HZ
> or not when setting this parameter instead. Then this check ins't necessary 
> here.
> 
> # Just FYI, MAX_SCHEDULE_TIMEOUT should be MAX_SCHEDULE_TIMEOUT/HZ here. 
> 
> Thanks,
> Satoru

 Yes, how about this :

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 49e13e1..aae21e8 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -144,6 +144,11 @@ static int min_percpu_pagelist_fract = 8;
 static int ngroups_max = NGROUPS_MAX;
 static const int cap_last_cap = CAP_LAST_CAP;

+/*this is needed for proc_doulongvec_minmax of sysctl_hung_task_timeout_secs */
+#ifdef CONFIG_DETECT_HUNG_TASK
+static unsigned long hung_task_timeout_max = (LONG_MAX/HZ);
+#endif
+
 #ifdef CONFIG_INOTIFY_USER
 #include <linux/inotify.h>
 #endif
@@ -995,6 +1000,7 @@ static struct ctl_table kern_table[] = {
                .maxlen         = sizeof(unsigned long),
                .mode           = 0644,
                .proc_handler   = proc_dohung_task_timeout_secs,
+               .extra2         = &hung_task_timeout_max,
        },
        {
                .procname       = "hung_task_warnings",
-- 
1.9.0

Thanks
Liu Hua



> 
>> +            return MAX_SCHEDULE_TIMEOUT;
>> +
>> +    return (timeout * HZ) < MAX_SCHEDULE_TIMEOUT ?
>> +                    timeout * HZ : MAX_SCHEDULE_TIMEOUT;
>>  }
>>  
>>  /*
>> -- 
>> 1.9.0
>>
>> --
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> 
> .
> 


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