Messages in this thread | | | Date | Thu, 22 Mar 2012 14:22:12 +0000 | From | Al Viro <> | Subject | Re: [PATCH v3 10/12] ima: defer calling __fput() |
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On Wed, Mar 21, 2012 at 02:54:15PM -0400, Mimi Zohar wrote: > If a file is closed before it is munmapped, __fput() is called with > the mmap_sem taken. With IMA-appraisal enabled, this results in an > mmap_sem/i_mutex lockdep. ima_defer_fput() increments the f_count > to defer __fput() being called until after the mmap_sem is released.
NAK. It's far too heavy-weight for what's a very common path. Worse, it causes different locking conditions on IMA and non-IMA kernels and makes bugs harder to spot. Rejected with extreme prejudice; please, fix your locking instead.
BTW, you've missed several other places in mm/* doing fput(), so it wouldn't be enough to paper over your problem anyway.
Final fput() *can* happen under mmap_sem. Period.
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