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| author | Dan Williams <dan.j.williams@intel.com> | 2019-08-05 18:31:56 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-08-09 17:52:28 +0200 |
| commit | d16bbdbbcb5002c5366cbf6402561d0350afd5fe (patch) | |
| tree | a580c2b6c595decd70e2b23153dceb705e74093e | |
| parent | c23106d4276d7d03f1b3e9dfca40fcf793a6ebab (diff) | |
| download | linux-stable-d16bbdbbcb5002c5366cbf6402561d0350afd5fe.tar.gz linux-stable-d16bbdbbcb5002c5366cbf6402561d0350afd5fe.tar.bz2 linux-stable-d16bbdbbcb5002c5366cbf6402561d0350afd5fe.zip | |
libnvdimm/bus: Prevent duplicate device_unregister() calls
commit 8aac0e2338916e273ccbd438a2b7a1e8c61749f5 upstream.
A multithreaded namespace creation/destruction stress test currently
fails with signatures like the following:
sysfs group 'power' not found for kobject 'dax1.1'
RIP: 0010:sysfs_remove_group+0x76/0x80
Call Trace:
device_del+0x73/0x370
device_unregister+0x16/0x50
nd_async_device_unregister+0x1e/0x30 [libnvdimm]
async_run_entry_fn+0x39/0x160
process_one_work+0x23c/0x5e0
worker_thread+0x3c/0x390
BUG: kernel NULL pointer dereference, address: 0000000000000020
RIP: 0010:klist_put+0x1b/0x6c
Call Trace:
klist_del+0xe/0x10
device_del+0x8a/0x2c9
? __switch_to_asm+0x34/0x70
? __switch_to_asm+0x40/0x70
device_unregister+0x44/0x4f
nd_async_device_unregister+0x22/0x2d [libnvdimm]
async_run_entry_fn+0x47/0x15a
process_one_work+0x1a2/0x2eb
worker_thread+0x1b8/0x26e
Use the kill_device() helper to atomically resolve the race of multiple
threads issuing kill, device_unregister(), requests.
Reported-by: Jane Chu <jane.chu@oracle.com>
Reported-by: Erwin Tsaur <erwin.tsaur@oracle.com>
Fixes: 4d88a97aa9e8 ("libnvdimm, nvdimm: dimm driver and base libnvdimm device-driver...")
Cc: <stable@vger.kernel.org>
Link: https://github.com/pmem/ndctl/issues/96
Tested-by: Tested-by: Jane Chu <jane.chu@oracle.com>
Link: https://lore.kernel.org/r/156341207846.292348.10435719262819764054.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | drivers/nvdimm/bus.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c index ee39e2c1644a..11cfd23e5aff 100644 --- a/drivers/nvdimm/bus.c +++ b/drivers/nvdimm/bus.c @@ -528,13 +528,38 @@ EXPORT_SYMBOL(nd_device_register); void nd_device_unregister(struct device *dev, enum nd_async_mode mode) { + bool killed; + switch (mode) { case ND_ASYNC: + /* + * In the async case this is being triggered with the + * device lock held and the unregistration work needs to + * be moved out of line iff this is thread has won the + * race to schedule the deletion. + */ + if (!kill_device(dev)) + return; + get_device(dev); async_schedule_domain(nd_async_device_unregister, dev, &nd_async_domain); break; case ND_SYNC: + /* + * In the sync case the device is being unregistered due + * to a state change of the parent. Claim the kill state + * to synchronize against other unregistration requests, + * or otherwise let the async path handle it if the + * unregistration was already queued. + */ + device_lock(dev); + killed = kill_device(dev); + device_unlock(dev); + + if (!killed) + return; + nd_synchronize(); device_unregister(dev); break; |