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node_device_udev: Serialize access to pci_get_strings)_

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Since the functions provided by libpciaccess are not thread-safe,
when the udev-event and nodedev-init threads of libvirt call the
pci_get_strings function provided by libpaciaccess at the same
time the following can happen:

nodedev-init thread:
nodeStateInitializeEnumerate ->
  udevEnumerateDevices->
    udevProcessDeviceListEntry ->
      udevAddOneDevice ->
        udevGetDeviceDetails->
          udevProcessPCI ->
            udevTranslatePCIIds ->
              pci_get_strings -> (libpciaccess)
                find_device_name ->
                  populate_vendor ->
                    d = realloc( vend->devices, (vend->num_devices + 1), * sizeof( struct pci_device_leaf ) );
                    vend->num_devices++;

udev-event thread:
udevEventHandleThread ->
  udevHandleOneDevice ->
    udevAddOneDevice->
      udevGetDeviceDetails->
        udevProcessPCI ->
          udevTranslatePCIIds ->
            pci_get_strings -> (libpciaccess)
              find_device_name ->
                populate_vendor ->
                  d = realloc( vend->devices, (vend->num_devices + 1), * sizeof( struct pci_device_leaf ) );
                  vend->num_devices++;

Signed-off-by: WangJian <wangjian161@huawei.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
This commit is contained in:
wangjian
2021-03-26 11:21:16 +08:00
committed by Michal Privoznik
parent 5f9330e724
commit 59788a5cae
1 changed files with 4 additions and 1 deletions
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5
src/node_device/node_device_udev.c
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@@ -331,6 +331,7 @@ udevGenerateDeviceName(struct udev_device *device,
return 0;
}
static virMutex pciaccessMutex = VIR_MUTEX_INITIALIZER;
static int
udevTranslatePCIIds(unsigned int vendor,
@@ -349,12 +350,14 @@ udevTranslatePCIIds(unsigned int vendor,
m.device_class_mask = 0;
m.match_data = 0;
/* pci_get_strings returns void */
/* pci_get_strings returns void and unfortunately is not thread safe. */
virMutexLock(&pciaccessMutex);
pci_get_strings(&m,
&device_name,
&vendor_name,
NULL,
NULL);
virMutexUnlock(&pciaccessMutex);
*vendor_string = g_strdup(vendor_name);
*product_string = g_strdup(device_name);