On Sun, Sep 12, 2010 at 09:41:46PM +0100, Robert Watson wrote: > > On Sun, 12 Sep 2010, Konstantin Belousov wrote: > > > Do not fork nfsiod directly from the vop methods. This causes LORs between > > vnode lock and several locks needed during fork, like fd lock. > > > > Instead, schedule the task to be executed in the taskqueue context. We > > still waiting for the fork to finish, but the context of the thread > > executing the task does not make real LORs with our vnode lock. > > Does this actually functionally improve things, or is all this complexity > about suppressing the lock order reversal? If we're waiting synchronously > for the other thread to launch from the task queue, then the lock order > reversal still exists, it's just not visible to WITNESS... If we had a > static analysis tool that could run on lock and sleep/wakeup traces, it > would still show a deadlock opportunity.
As I said in commit message, the deadlock should be fixed, because the taskq thread is executed in the kernel process that should even not have file descriptors at all.
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