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    SubjectRe: [linux-pm] Re: [PATCH] Remove process freezer from suspend to RAM pathway
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    > > > I have discussed the benefits elsewhere.  As for the deadlocks -- do 
    > > > you still observe them if you use the version of the freezer which
    > > > doesn't freeze kernel threads?
    > >
    > > In general the only way to guarantee there are no deadlocks is to
    > > construct the graph of dependencies between tasks.  Those dependencies
    > > are not in practice observable from outside the tasks, so it is
    > > virtually impossible to construct the graph.
    >
    > In which way can user space tasks depend on each other in a way that
    > allows a them members of that cycle to be in uninterruptible sleep?

    - process A calls rename() on a fuse fs
    - process B, the fuse server, starts to process the rename request
    - process B is frozen before it can reply

    Now process A is unfreezable. We cannot make rename() restartable,
    hence it cannot be interruptible.

    Miklos
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