On Wed, Jan 17, 2024 at 04:13:30PM +0100, Peter Krempa wrote:
Locks in following text:
A: virNetServer
B: virNetServerClient
C: daemonClientPrivate
'virNetServerSetClientAuthenticated' locks A then B
'remoteDispatchAuthPolkit' calls 'virNetServerSetClientAuthenticated'
while holding C.
If a client closes its connection 'virNetServerProcessClients' with the
lock A and B locked will call 'virNetServerClientCloseLocked' which will
try to dispose of the 'client' private data by:
ref(b);
unlock(b);
remoteClientFreePrivateCallbacks();
lock(b);
unref(b);
Unfortunately remoteClientFreePrivateCallbacks() tries lock C.
Thus the locks are held in the following order:
polkit auth: C -> A
connection close: A -> C
causing a textbook-example deadlock. To resolve it we can simply drop
lock 'C' before calling 'virNetServerSetClientAuthenticated' as the lock
is not needed any more.
Resolves:
https://issues.redhat.com/browse/RHEL-20337
Signed-off-by: Peter Krempa <pkrempa(a)redhat.com>
Reviewed-by: Martin Kletzander <mkletzan(a)redhat.com>