Re: 2.6.5-rc2-mm2 ipc hang fix

[Manfred Spraul <manfred@colorfullife.com>]

badari wrote:

>--- linux/ipc/sem.c     2004-03-26 05:19:22.833959160 -0800
>+++ linux.new/ipc/sem.c 2004-03-26 05:19:57.047757872 -0800
>@@ -972,8 +972,10 @@ static struct sem_undo *find_undo(int se
>        if(sma==NULL)
>                goto out;
>        un = ERR_PTR(-EIDRM);
>-       if (sem_checkid(sma,semid))
>+       if (sem_checkid(sma,semid)) {
>+               sem_unlock(sma);
>                goto out_unlock;
>+       }
>        nsems = sma->sem_nsems;
>        sem_unlock(sma);
>  
>
[snip]

> out_unlock:
>         unlock_semundo();
> out:
>         return un;
> }

Thanks for finding the bug - out_unlock unlocks the wrong spinlock, 
that's why I didn't notice it while searching for the bug.
But I think your fix is wrong: the "goto out_unlock" must be replaced 
with "goto out": the semundo spinlock is not held.

--
    Manfred