72 lines
2.3 KiB
Diff
72 lines
2.3 KiB
Diff
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From b85da76baeebccdb35c12bbc16f82692c42a7372 Mon Sep 17 00:00:00 2001
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From: Michal Privoznik <mprivozn@redhat.com>
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Date: Thu, 7 Jan 2021 15:51:02 +0100
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Subject: [PATCH 077/108] network: Introduce mutex for bridge name generation
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When defining/creating a network the bridge name may be filled in
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automatically by libvirt (if none provided in the input XML or
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the one provided is a pattern, e.g. "virbr%d"). During the
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bridge name generation process a candidate name is generated
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which is then checked with the rest of already defined/running
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networks for collisions.
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Problem is, that there is no mutex guarding this critical section
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and thus if two threads line up so that they both generate the
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same candidate they won't find any collision and the same name is
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then stored.
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Resolves: https://gitlab.com/libvirt/libvirt/-/issues/78
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Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
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Reviewed-by: Laine Stump <laine@redhat.com>
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(cherry picked from commit ea0cfa115307ecb9fe05dd1953ec7ddd8dd39d72)
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---
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src/network/bridge_driver.c | 13 +++++++++++--
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1 file changed, 11 insertions(+), 2 deletions(-)
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diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c
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index 21d02dd304..ce61ff483a 100644
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--- a/src/network/bridge_driver.c
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+++ b/src/network/bridge_driver.c
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@@ -74,6 +74,8 @@
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#define VIR_FROM_THIS VIR_FROM_NETWORK
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#define MAX_BRIDGE_ID 256
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+static virMutex bridgeNameValidateMutex = VIR_MUTEX_INITIALIZER;
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+
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/**
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* VIR_NETWORK_DHCP_LEASE_FILE_SIZE_MAX:
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*
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@@ -3255,20 +3257,27 @@ static int
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networkBridgeNameValidate(virNetworkObjListPtr nets,
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virNetworkDefPtr def)
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{
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+ virMutexLock(&bridgeNameValidateMutex);
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+
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if (def->bridge && !strstr(def->bridge, "%d")) {
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if (virNetworkObjBridgeInUse(nets, def->bridge, def->name)) {
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virReportError(VIR_ERR_INTERNAL_ERROR,
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_("bridge name '%s' already in use."),
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def->bridge);
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- return -1;
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+ goto error;
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}
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} else {
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/* Allocate a bridge name */
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if (networkFindUnusedBridgeName(nets, def) < 0)
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- return -1;
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+ goto error;
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}
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+ virMutexUnlock(&bridgeNameValidateMutex);
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return 0;
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+
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+ error:
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+ virMutexUnlock(&bridgeNameValidateMutex);
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+ return -1;
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}
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--
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2.33.0
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