From: Dan Williams <dan.j.williams@intel.com>
To: linux-nvdimm@lists.01.org
Cc: Jane Chu <jane.chu@oracle.com>,
Erwin Tsaur <erwin.tsaur@oracle.com>,
stable@vger.kernel.org, peterz@infradead.org,
vishal.l.verma@intel.com, linux-kernel@vger.kernel.org
Subject: [PATCH 2/6] libnvdimm/bus: Prevent duplicate device_unregister() calls
Date: Tue, 11 Jun 2019 16:25:54 -0700 [thread overview]
Message-ID: <156029555412.419799.17084493871021141653.stgit@dwillia2-desk3.amr.corp.intel.com> (raw)
In-Reply-To: <156029554317.419799.1324389595953183385.stgit@dwillia2-desk3.amr.corp.intel.com>
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
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
drivers/nvdimm/bus.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
index 2dca3034fee0..42713b210f51 100644
--- a/drivers/nvdimm/bus.c
+++ b/drivers/nvdimm/bus.c
@@ -547,13 +547,38 @@ 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;
next prev parent reply other threads:[~2019-06-11 23:40 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-11 23:25 [PATCH 0/6] libnvdimm: Fix async operations and locking Dan Williams
2019-06-11 23:25 ` [PATCH 1/6] drivers/base: Introduce kill_device() Dan Williams
2019-06-11 23:25 ` Dan Williams [this message]
2019-06-11 23:25 ` [PATCH 3/6] libnvdimm/region: Register badblocks before namespaces Dan Williams
2019-06-21 0:56 ` Verma, Vishal L
2019-06-11 23:26 ` [PATCH 4/6] libnvdimm/bus: Stop holding nvdimm_bus_list_mutex over __nd_ioctl() Dan Williams
2019-06-11 23:26 ` [PATCH 5/6] libnvdimm/bus: Fix wait_nvdimm_bus_probe_idle() ABBA deadlock Dan Williams
2019-06-11 23:26 ` [PATCH 6/6] driver-core, libnvdimm: Let device subsystems add local lockdep coverage Dan Williams
2019-06-19 22:21 ` Dan Williams
2019-06-20 6:34 ` Greg Kroah-Hartman
2019-06-18 22:10 ` [PATCH 0/6] libnvdimm: Fix async operations and locking Jane Chu
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