qemu/hw/xen
Paul Durrant 240cc11369 hw/xen: Avoid crash when backend watch fires too early
The xen-block code ends up calling aio_poll() through blkconf_geometry(),
which means we see watch events during the indirect call to
xendev_class->realize() in xen_device_realize(). Unfortunately this call
is made before populating the initial frontend and backend device nodes
in xenstore and hence xen_block_frontend_changed() (which is called from
a watch event) fails to read the frontend's 'state' node, and hence
believes the device is being torn down. This in-turn sets the backend
state to XenbusStateClosed and causes the device to be deleted before it
is fully set up, leading to the crash.
By simply moving the call to xendev_class->realize() after the initial
xenstore nodes are populated, this sorry state of affairs is avoided.

Reported-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Paul Durrant <pdurrant@amazon.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
2023-03-07 17:04:30 +00:00
..
Kconfig xen: add CONFIG_XEN_BUS and CONFIG_XEN_EMU options for Xen emulation 2023-03-01 08:22:49 +00:00
meson.build hw/xen: Build PV backend drivers for CONFIG_XEN_BUS 2023-03-07 17:04:30 +00:00
trace-events hw/xen: Rename xen_common.h to xen_native.h 2023-03-07 17:04:30 +00:00
trace.h
xen_devconfig.c hw/xen: Add xenstore operations to allow redirection to internal emulation 2023-03-07 17:04:30 +00:00
xen_pt_config_init.c hw/xen: Rename xen_common.h to xen_native.h 2023-03-07 17:04:30 +00:00
xen_pt_graphics.c hw/xen: Add xenstore operations to allow redirection to internal emulation 2023-03-07 17:04:30 +00:00
xen_pt_load_rom.c
xen_pt_msi.c hw/xen: Rename xen_common.h to xen_native.h 2023-03-07 17:04:30 +00:00
xen_pt_stub.c xen/pt: reserve PCI slot 2 for Intel igd-passthru 2023-03-06 11:27:37 +00:00
xen_pt.c hw/xen: Rename xen_common.h to xen_native.h 2023-03-07 17:04:30 +00:00
xen_pt.h hw/xen: Rename xen_common.h to xen_native.h 2023-03-07 17:04:30 +00:00
xen_pvdev.c hw/xen: Add xenstore operations to allow redirection to internal emulation 2023-03-07 17:04:30 +00:00
xen-backend.c
xen-bus-helper.c hw/xen: Add xenstore operations to allow redirection to internal emulation 2023-03-07 17:04:30 +00:00
xen-bus.c hw/xen: Avoid crash when backend watch fires too early 2023-03-07 17:04:30 +00:00
xen-host-pci-device.c
xen-host-pci-device.h
xen-legacy-backend.c hw/xen: Add xenstore operations to allow redirection to internal emulation 2023-03-07 17:04:30 +00:00
xen-operations.c hw/xen: Rename xen_common.h to xen_native.h 2023-03-07 17:04:30 +00:00