by Verma, Vishal L

[permalink] [raw]

Subject: Re: [PATCH 3/6] libnvdimm/region: Register badblocks before namespaces

On Tue, 2019-06-11 at 16:25 -0700, Dan Williams wrote:
> Namespace activation expects to be able to reference region badblocks.
> The following warning sometimes triggers when asynchronous namespace
> activation races in front of the completion of namespace probing. Move
> all possible namespace probing after region badblocks initialization.
>
> Otherwise, lockdep sometimes catches the uninitialized state of the
> badblocks seqlock with stack trace signatures like:
>
> INFO: trying to register non-static key.
> pmem2: detected capacity change from 0 to 136365211648
> the code is fine but needs lockdep annotation.
> turning off the locking correctness validator.
> CPU: 9 PID: 358 Comm: kworker/u80:5 Tainted:
> G OE 5.2.0-rc4+ #3382
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0
> 02/06/2015
> Workqueue: events_unbound async_run_entry_fn
> Call Trace:
> dump_stack+0x85/0xc0
> pmem1.12: detected capacity change from 0 to 8589934592
> register_lock_class+0x56a/0x570
> ? check_object+0x140/0x270
> __lock_acquire+0x80/0x1710
> ? __mutex_lock+0x39d/0x910
> lock_acquire+0x9e/0x180
> ? nd_pfn_validate+0x28f/0x440 [libnvdimm]
> badblocks_check+0x93/0x1f0
> ? nd_pfn_validate+0x28f/0x440 [libnvdimm]
> nd_pfn_validate+0x28f/0x440 [libnvdimm]
> ? lockdep_hardirqs_on+0xf0/0x180
> nd_dax_probe+0x9a/0x120 [libnvdimm]
> nd_pmem_probe+0x6d/0x180 [nd_pmem]
> nvdimm_bus_probe+0x90/0x2c0 [libnvdimm]
>
> Fixes: 48af2f7e52f4 ("libnvdimm, pfn: during init, clear errors...")
> Cc: <[email protected]>
> Cc: Vishal Verma <[email protected]>
> Signed-off-by: Dan Williams <[email protected]>
> ---
> drivers/nvdimm/region.c | 22 +++++++++++-----------
> 1 file changed, 11 insertions(+), 11 deletions(-)

This looks good to me,
Reviewed-by: Vishal Verma <[email protected]>

>
> diff --git a/drivers/nvdimm/region.c b/drivers/nvdimm/region.c
> index ef46cc3a71ae..488c47ac4c4a 100644
> --- a/drivers/nvdimm/region.c
> +++ b/drivers/nvdimm/region.c
> @@ -34,17 +34,6 @@ static int nd_region_probe(struct device *dev)
> if (rc)
> return rc;
>
> - rc = nd_region_register_namespaces(nd_region, &err);
> - if (rc < 0)
> - return rc;
> -
> - ndrd = dev_get_drvdata(dev);
> - ndrd->ns_active = rc;
> - ndrd->ns_count = rc + err;
> -
> - if (rc && err && rc == err)
> - return -ENODEV;
> -
> if (is_nd_pmem(&nd_region->dev)) {
> struct resource ndr_res;
>
> @@ -60,6 +49,17 @@ static int nd_region_probe(struct device *dev)
> nvdimm_badblocks_populate(nd_region, &nd_region->bb,
> &ndr_res);
> }
>
> + rc = nd_region_register_namespaces(nd_region, &err);
> + if (rc < 0)
> + return rc;
> +
> + ndrd = dev_get_drvdata(dev);
> + ndrd->ns_active = rc;
> + ndrd->ns_count = rc + err;
> +
> + if (rc && err && rc == err)
> + return -ENODEV;
> +
> nd_region->btt_seed = nd_btt_create(nd_region);
> nd_region->pfn_seed = nd_pfn_create(nd_region);
> nd_region->dax_seed = nd_dax_create(nd_region);
>