> -----Original Message----- > From: Vitaly Kuznetsov [mailto:vkuznets@xxxxxxxxxx] > Sent: Wednesday, January 21, 2015 11:02 AM > To: KY Srinivasan; devel@xxxxxxxxxxxxxxxxxxxxxx > Cc: Haiyang Zhang; linux-kernel@xxxxxxxxxxxxxxx; Dexuan Cui > Subject: [PATCH 2/3] Drivers: hv: vmbus: introduce vmbus_acpi_remove > > In case we do request_resource() in vmbus_acpi_add() we need to tear it > down to be able to load the driver again. Otherwise the following crash in > oberved when hv_vmbus unload/load sequence is performed on > Generation2 instance: > > [ 38.165701] BUG: unable to handle kernel paging request at ffffffffa00075a0 > [ 38.166315] IP: [<ffffffff8107dc5f>] __request_resource+0x2f/0x50 > [ 38.166315] PGD 1f34067 PUD 1f35063 PMD 3f723067 PTE 0 > [ 38.166315] Oops: 0000 [#1] SMP > [ 38.166315] Modules linked in: hv_vmbus(+) [last unloaded: hv_vmbus] > [ 38.166315] CPU: 0 PID: 267 Comm: modprobe Not tainted 3.19.0- > rc5_bug923184+ #486 > [ 38.166315] Hardware name: Microsoft Corporation Virtual Machine/Virtual > Machine, BIOS Hyper-V UEFI Release v1.0 11/26/2012 > [ 38.166315] task: ffff88003f401cb0 ti: ffff88003f60c000 task.ti: > ffff88003f60c000 > [ 38.166315] RIP: 0010:[<ffffffff8107dc5f>] [<ffffffff8107dc5f>] > __request_resource+0x2f/0x50 > [ 38.166315] RSP: 0018:ffff88003f60fb58 EFLAGS: 00010286 > ... > > Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> > --- > drivers/hv/vmbus_drv.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index > 4d6b269..b06cb87 100644 > --- a/drivers/hv/vmbus_drv.c > +++ b/drivers/hv/vmbus_drv.c > @@ -902,6 +902,15 @@ acpi_walk_err: > return ret_val; > } > > +static int vmbus_acpi_remove(struct acpi_device *device) { > + int ret = 0; > + > + if (hyperv_mmio.start && hyperv_mmio.end) > + ret = release_resource(&hyperv_mmio); > + return ret; > +} > + > static const struct acpi_device_id vmbus_acpi_device_ids[] = { > {"VMBUS", 0}, > {"VMBus", 0}, > @@ -914,6 +923,7 @@ static struct acpi_driver vmbus_acpi_driver = { > .ids = vmbus_acpi_device_ids, > .ops = { > .add = vmbus_acpi_add, > + .remove = vmbus_acpi_remove, > }, > }; Vitaly, Jake has sent the following patch that has fixed retrieving of the mmio resources: https://lkml.org/lkml/2015/1/20/876 This patch also deals with the resource cleanup that you have in this patch. Regards, K. Y > > -- > 1.9.3 _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
