Maciej S. Szmigiero 96db43aced Drivers: hv: vmbus: Don't dereference ACPI root object handle ... [ Upstream commit 78e04bbff8 ] Since the commit referenced in the Fixes: tag below the VMBus client driver is walking the ACPI namespace up from the VMBus ACPI device to the ACPI namespace root object trying to find Hyper-V MMIO ranges. However, if it is not able to find them it ends trying to walk resources of the ACPI namespace root object itself. This object has all-ones handle, which causes a NULL pointer dereference in the ACPI code (from dereferencing this pointer with an offset). This in turn causes an oops on boot with VMBus host implementations that do not provide Hyper-V MMIO ranges in their VMBus ACPI device or its ancestors. The QEMU VMBus implementation is an example of such implementation. I guess providing these ranges is optional, since all tested Windows versions seem to be able to use VMBus devices without them. Fix this by explicitly terminating the lookup at the ACPI namespace root object. Note that Linux guests under KVM/QEMU do not use the Hyper-V PV interface by default - they only do so if the KVM PV interface is missing or disabled. Example stack trace of such oops: [ 3.710827] ? __die+0x1f/0x60 [ 3.715030] ? page_fault_oops+0x159/0x460 [ 3.716008] ? exc_page_fault+0x73/0x170 [ 3.716959] ? asm_exc_page_fault+0x22/0x30 [ 3.717957] ? acpi_ns_lookup+0x7a/0x4b0 [ 3.718898] ? acpi_ns_internalize_name+0x79/0xc0 [ 3.720018] acpi_ns_get_node_unlocked+0xb5/0xe0 [ 3.721120] ? acpi_ns_check_object_type+0xfe/0x200 [ 3.722285] ? acpi_rs_convert_aml_to_resource+0x37/0x6e0 [ 3.723559] ? down_timeout+0x3a/0x60 [ 3.724455] ? acpi_ns_get_node+0x3a/0x60 [ 3.725412] acpi_ns_get_node+0x3a/0x60 [ 3.726335] acpi_ns_evaluate+0x1c3/0x2c0 [ 3.727295] acpi_ut_evaluate_object+0x64/0x1b0 [ 3.728400] acpi_rs_get_method_data+0x2b/0x70 [ 3.729476] ? vmbus_platform_driver_probe+0x1d0/0x1d0 [hv_vmbus] [ 3.730940] ? vmbus_platform_driver_probe+0x1d0/0x1d0 [hv_vmbus] [ 3.732411] acpi_walk_resources+0x78/0xd0 [ 3.733398] vmbus_platform_driver_probe+0x9f/0x1d0 [hv_vmbus] [ 3.734802] platform_probe+0x3d/0x90 [ 3.735684] really_probe+0x19b/0x400 [ 3.736570] ? __device_attach_driver+0x100/0x100 [ 3.737697] __driver_probe_device+0x78/0x160 [ 3.738746] driver_probe_device+0x1f/0x90 [ 3.739743] __driver_attach+0xc2/0x1b0 [ 3.740671] bus_for_each_dev+0x70/0xc0 [ 3.741601] bus_add_driver+0x10e/0x210 [ 3.742527] driver_register+0x55/0xf0 [ 3.744412] ? 0xffffffffc039a000 [ 3.745207] hv_acpi_init+0x3c/0x1000 [hv_vmbus] Fixes: 7f163a6fd9 ("drivers:hv: Modify hv_vmbus to search for all MMIO ranges available.") Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Wei Liu <wei.liu@kernel.org> Link: https://lore.kernel.org/r/fd8e64ceeecfd1d95ff49021080cf699e88dbbde.1691606267.git.maciej.szmigiero@oracle.com Signed-off-by: Sasha Levin <sashal@kernel.org>		2023-09-13 09:42:59 +02:00
..
channel.c
channel_mgmt.c	Drivers: hv: vmbus: Fix vmbus_wait_for_unload() to scan present CPUs	2023-06-28 11:12:23 +02:00
connection.c	Drivers: vmbus: Check for channel allocation before looking up relids	2023-04-13 16:55:18 +02:00
hv.c
hv_balloon.c	HV: hv_balloon: fix memory leak with using debugfs_lookup()	2023-02-09 11:28:21 +01:00
hv_common.c
hv_debugfs.c
hv_fcopy.c
hv_kvp.c
hv_snapshot.c
hv_trace.c
hv_trace.h
hv_trace_balloon.h
hv_util.c
hv_utils_transport.c
hv_utils_transport.h
hyperv_vmbus.h
Kconfig
Makefile
ring_buffer.c	video: hyperv_fb: Avoid taking busy spinlock on panic path	2022-12-31 13:32:56 +01:00
vmbus_drv.c	Drivers: hv: vmbus: Don't dereference ACPI root object handle	2023-09-13 09:42:59 +02:00