Xen devel - Apr 2007 - race with restart and device removal

We''ve observed that sometimes during restart some of a
domain''s vbds
failed to be created. From some debugging it appears to be this code:

        # Marshall devices (running or from configuration)
        if not ignore_devices:
            for cls in XendDevices.valid_devices():
                found = False

                # figure if there is a device that is running
                if domain:
                    try:
                        controller = domain.getDeviceController(cls)
                        configs = controller.configurations()
                        for config in configs:
                            sxpr.append([''device'', config])
                            found = True
                    except:
                        log.exception("dumping sxp from device
controllers")
                        pass

                # if we didn''t find that device, check the existing
config
                # for a device in the same class
                if not found:
                    for dev_type, dev_info in self.all_devices_sxpr():
                        if dev_type == cls:
                            sxpr.append([''device'', dev_info])

''configs'' comes from the xen store:

    def deviceIDs(self, transaction = None):
        """@return The IDs of each of the devices currently
configured for
        this instance''s deviceClass.
        """
        fe = self.backendRoot()
        if transaction:
            return map(lambda x: int(x.split(''/'')[-1]),
transaction.list(fe))
        else:
            return map(int, xstransact.List(fe))


But this can race against the disk backend removing the xenstore entries
itself: so we may have removed one device but not the other.

I wonder why we''re looking at the running devices at all here?
What''s the best fix?

thanks
john

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Hi,

When I try to do make install to build Xen with the latest xen-unstable on a
fresh RHEL 4U4, I got the following warnings (make world is fine). Does
anyone know how to solve these problems? BTW, I enabled the OProfile setting
for linux-2.6.18-xen. I''m not sure if this is related to the following
warnings:

WRNING: drivers/atm/fore_200e.o - Section mismatch: reference to .init.text:
from .text between ''fore200e_i nitialize'' (at offset 0x29df)
and
''fore200e_monitor_putc''
WARNING: drivers/atm/he.o - Section mismatch: reference to .init.text: from
text between ''he_start'' (at off set 0x50c) and
''he_stop''
WARNING: drivers/atm/he.o - Section mismatch: reference to .init.text: from
text between ''he_start'' (at off set 0x8b8) and
''he_stop''
WARNING: drivers/atm/he.o - Section mismatch: reference to .init.text: from
text between ''he_start'' (at off set 0x8bf) and
''he_stop''
WARNING: drivers/atm/he.o - Section mismatch: reference to .init.text: from
text between ''he_start'' (at off set 0x901) and
''he_stop''
WARNING: drivers/atm/he.o - Section mismatch: reference to .init.text: from
text between ''he_start'' (at off set 0xa3c) and
''he_stop''
WARNING: drivers/atm/he.o - Section mismatch: reference to .init.text: from
text between ''he_start'' (at off set 0xa43) and
''he_stop''
WARNING: drivers/atm/he.o - Section mismatch: reference to .init.text: from
text between ''he_start'' (at off set 0xa59) and
''he_stop''
WARNING: drivers/atm/he.o - Section mismatch: reference to .init.text: from
text between ''he_start'' (at off set 0xaa2) and
''he_stop''
WARNING: drivers/atm/horizon.o - Section mismatch: reference to .init.text:
from .text between ''hrz_probe'' ( at offset 0x19dd) and
''hrz_remove_one''
WARNING: drivers/atm/lanai.o - Section mismatch: reference to .init.text:
from .text between ''sram_test_pass '' (at offset 0x207) and
''sram_test_and_clear''
WARNING: drivers/atm/zatm.o - Section mismatch: reference to .init.text:
from .text after ''zatm_init_one'' (a t offset 0x2854)
WARNING: drivers/atm/zatm.o - Section mismatch: reference to .init.text:
from .text after ''zatm_init_one'' (a t offset 0x2861)
WARNING: drivers/net/rrunner.o - Section mismatch: reference to
init.text:rr_init from .text between ''rr_in it_one'' (at offset
0x22b) and
''rr_remove_one''
WARNING: drivers/net/sis900.o - Section mismatch: reference to
init.text:sis900_mii_probe from .text betwee n ''sis900_probe''
(at offset
0x539) and ''sis900_default_phy''
WARNING: drivers/net/sunhme.o - Section mismatch: reference to .init.text:
from .text between ''happy_meal_pc i_probe'' (at offset 0x3816)
and
''happy_meal_pci_remove''
WARNING: drivers/net/tokenring/3c359.o - Section mismatch: reference to
init.text:xl_init from .text betwee n ''xl_probe'' (at offset
0x228) and
''xl_hw_reset''

Thanks,

Liang


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