Daniel P. Berrangé 7cb03e6a28 rpc: fix race in waking up client event loop
The first thread to issue a client RPC request will own the event
loop execution, sitting in the virNetClientIOEventLoop function.

It releases the client lock while running:

   virNetClientUnlock()
   g_main_loop_run()
   virNetClientLock()

If a second thread arrives with an RPC request, it will queue it
for the first thread to process. To inform the first thread that
there's a new request it calls g_main_loop_quit() to break it out
of the main loop.

This works if the first thread is in g_main_loop_run() at that
time. There is a small window of opportunity, however, where
the first thread has released the client lock, but not yet got
into g_main_loop_run(). If that happens, the wakeup from the
second thread is lost.

This patch deals with that by changing the way the wakeup is
performed. Instead of directly calling g_main_loop_quit(), the
second thread creates an idle source to run the quit function
from within the first thread. This guarantees that the first
thread will see the wakeup.

Tested by: Fima Shevrin <efim.shevrin@virtuozzo.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2024-01-09 11:58:41 +00:00
2019-05-31 17:54:28 +02:00
2024-01-09 09:45:49 +01:00
2024-01-09 12:07:20 +01:00
2019-09-06 12:47:46 +02:00
2022-03-17 14:33:12 +01:00
2023-11-23 18:32:03 +01:00
2023-12-05 11:48:28 +01:00
2020-08-03 09:26:48 +02:00
2019-10-18 17:32:52 +02:00
2015-06-16 13:46:20 +02:00
2023-08-23 14:22:36 -05:00

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==============================
Libvirt API for virtualization
==============================

Libvirt provides a portable, long term stable C API for managing the
virtualization technologies provided by many operating systems. It
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Hypervisor.

For some of these hypervisors, it provides a stateful management
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mappings into object systems such as GObject, CIM and SNMP.

Further information about the libvirt project can be found on the
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https://libvirt.org


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=======

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============

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============

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=======

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