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2018-03-12docs: document atomic_load_acquire and atomic_store_releasePaolo Bonzini
We will use them in the next patch, document what they do. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-09-21memory: avoid "resurrection" of dead FlatViewsPaolo Bonzini
It's possible for address_space_get_flatview() as it currently stands to cause a use-after-free for the returned FlatView, if the reference count is incremented after the FlatView has been replaced by a writer: thread 1 thread 2 RCU thread ------------------------------------------------------------- rcu_read_lock read as->current_map set as->current_map flatview_unref '--> call_rcu flatview_ref [ref=1] rcu_read_unlock flatview_destroy <badness> Since FlatViews are not updated very often, we can just detect the situation using a new atomic op atomic_fetch_inc_nonzero, similar to Linux's atomic_inc_not_zero, which performs the refcount increment only if it hasn't already hit zero. This is similar to Linux commit de09a9771a53 ("CRED: Fix get_task_cred() and task_state() to not resurrect dead credentials", 2010-07-29). Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-09-21atomic: update documentationPaolo Bonzini
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-06-07docs: create config/, devel/ and spin/ subdirectoriesPaolo Bonzini
Developer documentation should be its own manual. As a start, move all developer-oriented files to a separate directory. Also move non-text files to their own directories: docs/config/ for QEMU -readconfig input, and docs/spin/ for formal models to be used with the SPIN model checker. Reviewed-by: Daniel P. Berrange <berrange@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>