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Message-ID: <4063C65E.3030608@colorfullife.com>
Date: Fri, 26 Mar 2004 06:57:50 +0100
From: Manfred Spraul <manfred@colorfullife.com>
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To: badari <pbadari@us.ibm.com>
CC: andrew <akpm@osdl.org>, lkml <linux-kernel@vger.kernel.org>
Subject: Re: 2.6.5-rc2-mm2 ipc hang fix
References: <40638D1F.C296F528@us.ibm.com>
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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