On Sat, Nov 7, 2015 at 10:57 AM, Dan Williams <dan.j.williams@xxxxxxxxx> wrote:
> Rafael, awaiting your ack...
>
> Vishal, one thing I'll fix up on applying...
>
> On Tue, Oct 27, 2015 at 3:58 PM, Vishal Verma <vishal.l.verma@xxxxxxxxx> wrote:
>> Add a .notify callback to the acpi_nfit_driver that gets called on a
>> hotplug event. From this, evaluate the _FIT ACPI method which returns
>> the updated NFIT with handles for the hot-plugged NVDIMM.
>>
>> Iterate over the new NFIT, and add any new tables found, and
>> register/enable the corresponding regions.
>>
>> In the nfit test framework, after normal initialization, update the NFIT
>> with a new hot-plugged NVDIMM, and directly call into the driver to
>> update its view of the available regions.
>>
>> Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
>> Cc: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
>> Cc: Toshi Kani <toshi.kani@xxxxxxx>
>> Cc: Elliott, Robert <elliott@xxxxxxx>
>> Cc: Jeff Moyer <jmoyer@xxxxxxxxxx>
>> Cc: <linux-acpi@xxxxxxxxxxxxxxx>
>> Cc: <linux-nvdimm@xxxxxxxxxxxx>
>> Signed-off-by: Vishal Verma <vishal.l.verma@xxxxxxxxx>
> [..]
>
>> +static int acpi_nfit_add(struct acpi_device *adev)
>> +{
>> + struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER, NULL };
>> + struct acpi_nfit_desc *acpi_desc;
>> + struct device *dev = &adev->dev;
>> + struct acpi_table_header *tbl;
>> + acpi_status status = AE_OK;
>> + acpi_size sz;
>> + int rc = 0;
>> +
>> + device_lock(dev);
>
> The device is already locked by the time we reach this point. The
> unit tests don't trip this path which might be why this wasn't seen
> earlier.
The lockup call trace if you're interested:
dracut:/# [ 376.030455] INFO: task systemd-udevd:278 blocked for more
than 120 seconds.
[ 376.032561] Tainted: G O 4.3.0-rc6+ #1747
[ 376.034376] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
disables this message.
[ 376.036704] systemd-udevd D 0000000000000000 0 278 262 0x00000004
[ 376.039758] ffff880352a0ba60 0000000000000092 ffff880352a0ba88
ffff880361e57b98
[ 376.043779] ffff88035f150000 ffff880352ea5dc0 ffff880352a0c000
0000000000000246
[ 376.047800] ffff880359a43148 ffff880352ea5dc0 00000000ffffffff
ffff880352a0ba78
[ 376.051821] Call Trace:
[ 376.052882] [<ffffffff818e8b43>] schedule+0x33/0x80
[ 376.054527] [<ffffffff818e8eae>] schedule_preempt_disabled+0xe/0x10
[ 376.056493] [<ffffffff818eaf2f>] mutex_lock_nested+0x14f/0x3a0
[ 376.058361] [<ffffffffa003140e>] ? acpi_nfit_add+0x4e/0x150 [nfit]
[ 376.060310] [<ffffffffa003140e>] acpi_nfit_add+0x4e/0x150 [nfit]
[ 376.062283] [<ffffffff81584310>] ? devices_kset_move_last+0x60/0x90
[ 376.064250] [<ffffffff814d61c0>] acpi_device_probe+0x4f/0xf5
[ 376.066076] [<ffffffff81588244>] driver_probe_device+0x224/0x480
[ 376.067983] [<ffffffff81588528>] __driver_attach+0x88/0x90
[ 376.069769] [<ffffffff815884a0>] ? driver_probe_device+0x480/0x480
[ 376.071716] [<ffffffff81585d83>] bus_for_each_dev+0x73/0xc0
[ 376.073522] [<ffffffff81587b9e>] driver_attach+0x1e/0x20
[ 376.075267] [<ffffffff815876de>] bus_add_driver+0x1ee/0x280
[ 376.077072] [<ffffffffa0038000>] ? 0xffffffffa0038000
[ 376.078757] [<ffffffff81588f10>] driver_register+0x60/0xe0
[ 376.080543] [<ffffffff814d6095>] acpi_bus_register_driver+0x40/0x42
[ 376.082511] [<ffffffffa00380ce>] nfit_init+0xce/0x1000 [nfit]
...fixed by the following incremental change:
diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
index 869f279fde95..a2e99ccf0480 100644
--- a/drivers/acpi/nfit.c
+++ b/drivers/acpi/nfit.c
@@ -1732,22 +1732,19 @@ static int acpi_nfit_add(struct acpi_device *adev)
struct acpi_table_header *tbl;
acpi_status status = AE_OK;
acpi_size sz;
- int rc = 0;
- device_lock(dev);
status = acpi_get_table_with_size("NFIT", 0, &tbl, &sz);
if (ACPI_FAILURE(status)) {
/* This is ok, we could have an nvdimm hotplugged later */
dev_dbg(dev, "failed to find NFIT at startup\n");
- goto out_unlock;
+ return 0;
}
acpi_desc = acpi_nfit_desc_init(adev);
if (IS_ERR(acpi_desc)) {
dev_err(dev, "%s: error initializing acpi_desc: %ld\n",
__func__, PTR_ERR(acpi_desc));
- rc = PTR_ERR(acpi_desc);
- goto out_unlock;
+ return PTR_ERR(acpi_desc);
}
acpi_desc->nfit = (struct acpi_table_nfit *) tbl;
@@ -1762,12 +1759,9 @@ static int acpi_nfit_add(struct acpi_device *adev)
rc = acpi_nfit_init(acpi_desc, sz);
if (rc) {
nvdimm_bus_unregister(acpi_desc->nvdimm_bus);
- goto out_unlock;
+ return rc;
}
-
- out_unlock:
- device_unlock(dev);
- return rc;
+ return 0;
}
--
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