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SubjectRe: [PATCH] do_wait fix for 2.6.10-rc1
On Fri, Nov 05, 2004 at 11:17:44AM -0800, Linus Torvalds wrote:

>> I think the real fix is to notice when we have dropped the tasklist_lock
>> inside the loop, and _not_ re-schedule in that case, but just repeat the
>> loop from the top.
>>
>> And that's easy enough to do: set current->state to TASK_RUNNING in the
>> cases where we might have raced with somebody else. That will cause the
>> schedule() to be a no-op.
>>
>> We could also choose to just wake up all our siblings "child_wait" lists
>> when we reap a child ourselves. They likely got woken up _anyway_ when the
>> child died in the first place, after all. For extra bonus points, make the
>> child_wait thing use the self-removing waitqueue entries, ie use
>> "prepare_to_wait()" instead of add_wait_queue(), and move it after the
>> "repeat:" thing.
>>
>> Linus
>
>

Linus,

Thanks for your suggestions. I have attached the re-done patch. I have
implemented your first suggestion because it was much easier. I hope it
looks better now.

Thanks and regards,
Sripathi Kodi.

Signed-off-by: Sripathi Kodi <sripathik@in.ibm.com>

--- linux-2.6.10-rc1/kernel/exit.c 2004-11-08 23:38:17.358375128 +0530
+++ /home/sripathi/12013/patch/take2/exit.c 2004-11-08 23:33:44.973783880 +0530
@@ -1345,8 +1345,10 @@ repeat:
break;
default:
// case EXIT_DEAD:
- if (p->exit_state == EXIT_DEAD)
- continue;
+ if (p->exit_state == EXIT_DEAD) {
+ current->state = TASK_RUNNING;
+ break;
+ }
// case EXIT_ZOMBIE:
if (p->exit_state == EXIT_ZOMBIE) {
/*
@@ -1363,6 +1365,7 @@ repeat:
/* He released the lock. */
if (retval != 0)
goto end;
+ current->state = TASK_RUNNING;
break;
}
check_continued:

-
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