Re: [PATCH -mm -next] ipc,sem: untangle RCU locking with find_alloc_undo

From: Sasha Levin
Date: Thu Mar 28 2013 - 21:15:37 EST


On 03/28/2013 09:00 PM, Michel Lespinasse wrote:
> On Thu, Mar 28, 2013 at 8:32 AM, Rik van Riel <riel@xxxxxxxxxxx> wrote:
>> The ipc semaphore code has a nasty RCU locking tangle, with both
>> find_alloc_undo and semtimedop taking the rcu_read_lock(). The
>> code can be cleaned up somewhat by only taking the rcu_read_lock
>> once.
>>
>> The only caller of find_alloc_undo is in semtimedop.
>>
>> This should solve the trinity issue reported by Sasha Levin.
>>
>> Reported-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
>> Signed-off-by: Rik van Riel <riel@xxxxxxxxxx>
>
> Looks good^Wbetter. I have nothing specific to say other than I've
> been staring at it for 10 minutes :)
>
> Reviewed-by: Michel Lespinasse <walken@xxxxxxxxxx>

And the warnings are gone:

Tested-by: Sasha Levin <sasha.levin@xxxxxxxxxx>


Thanks,
Sasha
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