[Xen-devel] [PATCH 1/4] libxl: event handling: Add an assert to egc_run_callbacks

[Ian Jackson <ian.jackson@xxxxxxxxxxxxx>]

Check that the ao is still live when we are about to running some of
its callbacks.

This reveals an existing bug in libxl which is exercised by libvirt,
converting
   libvirtd: libxl_event.c:1792: libxl__ao_complete_check_progress_reports: 
Assertion `ao->in_initiator' failed.
into
   libvirtd: libxl_event.c:1338: egc_run_callbacks: Assertion `aop->ao->magic 
== 0xA0FACE00ul' failed.

Signed-off-by: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
CC: Ian Campbell <ian.campbell@xxxxxxxxxx>
CC: Wei Liu <wei.liu2@xxxxxxxxxx>
CC: Jim Fehlig <jfehlig@xxxxxxxx>
---
 tools/libxl/libxl_event.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/libxl/libxl_event.c b/tools/libxl/libxl_event.c
index 0d874d9..ae73728 100644
--- a/tools/libxl/libxl_event.c
+++ b/tools/libxl/libxl_event.c
@@ -1335,6 +1335,7 @@ static void egc_run_callbacks(libxl__egc *egc)
         aop->how->callback(CTX, aop->ev, aop->how->for_callback);
 
         CTX_LOCK;
+        assert(aop->ao->magic == LIBXL__AO_MAGIC);
         aop->ao->progress_reports_outstanding--;
         libxl__ao_complete_check_progress_reports(egc, aop->ao);
         CTX_UNLOCK;
-- 
1.7.10.4


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