Re: [EDT][PATCH] kernel/exit.c : Fix missing read_unlock

Maninder Singh
2015-05-22T03:36:55Z

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EP-F6AA0618C49C4AEDA73BFF1B39950BAB

Hi Oleg,

>> Hi,
>>
>> From: Maninder Singh <maninder1.s@samsung.com>
>>
>> Subject: [PATCH 1/1] kernel/exit.c : Fix missing task_unlock
>>
>> This patch adds missing read_unlock if do_wait_thread or ptrace_do_wait
>> returns non zero.
>
>Confused...
>
>wait_consider_task() should drop tasklist_lock if it returns non-zero?
>
>
>> --- a/kernel/exit.c
>> +++ b/kernel/exit.c
>> @@ -1486,12 +1486,16 @@ repeat:
>> tsk = current;
>> do {
>> retval = do_wait_thread(wo, tsk);
>> - if (retval)
>> + if (retval) {
>> + read_unlock(&tasklist_lock);
>> goto end;
>> + }
>>
>> retval = ptrace_do_wait(wo, tsk);
>> - if (retval)
>> + if (retval) {
>> + read_unlock(&tasklist_lock);
>> goto end;
>> + }
>
>Well, the patch is obviously wrong. Because, again, tasklist_lock was
>already unlocked if (say) wait_task_zombie() reaps a child.

Yes, agree, My wrong
>If you think there is a case which forgets to unlock, please tell us
>more.
I have checked It is getting unlocked in wait_task_zombie Sorry for unnecessary disturbance.

>Oleg.
Thanks

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