Messages in this thread | | | Date | Wed, 19 Sep 2007 16:07:26 +0200 | From | Jarek Poplawski <> | Subject | Re: 2.6.23-rc6-mm1: IPC: sleeping function called ... |
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On 18-09-2007 16:55, Nadia Derbey wrote: ... > > Well, reviewing the code I found another place where the > rcu_read_unlock() was missing. > I'm so sorry for the inconvenience. It's true that I should have tested > with CONFIG_PREEMPT=y :-( > Now, the ltp tests pass even with this option set... > > In attachment you'll find a patch thhat > 1) adds the missing rcu_read_unlock() > 2) replaces Andrew's fix with a new one: the rcu_read_lock() is now > taken in ipc_lock() / ipc_lock_by_ptr() and released in ipc_unlock(), > exactly as it was done in the ref code.
BTW, probably I miss something, but I wonder, how this RCU is working here. E.g. in msg.c do_msgsnd() there is:
msq = msg_lock_check(ns, msqid); ...
msg_unlock(msq); schedule();
ipc_lock_by_ptr(&msq->q_perm);
Since msq_lock_check() gets msq with ipc_lock_check() under rcu_read_lock(), and then goes msg_unlock(msq) (i.e. ipc_unlock()) with rcu_read_unlock(), is it valid to use this with ipc_lock_by_ptr() yet?
Regards, Jarek P. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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