When a PCI device is unplugged, the PCI memory regions are deleted
before the optional ROM RAMBlock is flagged non-migratable. But, when
this is done, the RAMBlock has already been cleared from the region,
leading to a segv.
Fix the issue by testing the RAMBlock before flagging it, as it is
done in qemu_ram_unset_idstr()
Signed-off-by: Cédric Le Goater <c...@kaod.org>
---
I caught this bug while deleting a passthrough device from a pseries
machine. Here is the stack:
#0 qemu_ram_unset_migratable (rb=0x0) at
/home/legoater/work/qemu/qemu-xive-3.0.git/exec.c:1994
#1 0x000000010072def0 in vmstate_unregister_ram (mr=0x101796af0,
dev=<optimized out>)
#2 0x0000000100694e5c in pci_del_option_rom (pdev=0x101796330)
#3 pci_qdev_unrealize (dev=<optimized out>, errp=<optimized out>)
#4 0x00000001005ff910 in device_set_realized (obj=0x101796330,
value=<optimized out>, errp=0x0)
#5 0x00000001007a487c in property_set_bool (obj=0x101796330, v=<optimized
out>, name=<optimized out>,
#6 0x00000001007a7878 in object_property_set (obj=0x101796330,
v=0x7fff70033110,
#7 0x00000001007aaf1c in object_property_set_qobject (obj=0x101796330,
value=<optimized out>,
#8 0x00000001007a7b90 in object_property_set_bool (obj=0x101796330,
value=<optimized out>,
#9 0x00000001005fcdd8 in device_unparent (obj=0x101796330)
#10 0x00000001007a6dd0 in object_finalize_child_property (obj=<optimized
out>, name=<optimized out>,
#11 0x00000001007a50c0 in object_property_del_child (obj=0x10111f800,
child=0x101796330,
#12 0x0000000100425cc0 in spapr_phb_remove_pci_device_cb (dev=0x101796330)
#13 0x0000000100427974 in spapr_drc_release (drc=0x1017e2df0)
#14 0x0000000100429098 in spapr_drc_detach (drc=0x1017e2df0)
#15 0x00000001004294e0 in drc_isolate_physical (drc=0x1017e2df0)
#16 0x000000010042a50c in rtas_set_isolation_state (state=0, idx=<optimized
out>)
May be we should call pci_del_option_rom() before
pci_unregister_io_regions() ?
exec.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/exec.c b/exec.c
index ebadc0e302ad..0dabf7380438 100644
--- a/exec.c
+++ b/exec.c
@@ -1992,7 +1992,9 @@ void qemu_ram_set_migratable(RAMBlock *rb)
void qemu_ram_unset_migratable(RAMBlock *rb)
{
- rb->flags &= ~RAM_MIGRATABLE;
+ if (rb) {
+ rb->flags &= ~RAM_MIGRATABLE;
+ }
}
/* Called with iothread lock held. */
--
2.13.6
