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libnvdimm/bus: Prevent duplicate device_unregister() calls
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: 4d88a97aa9
("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>
This commit is contained in:
parent
00289cd876
commit
8aac0e2338
@ -547,13 +547,38 @@ EXPORT_SYMBOL(nd_device_register);
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void nd_device_unregister(struct device *dev, enum nd_async_mode mode)
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{
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bool killed;
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switch (mode) {
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case ND_ASYNC:
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/*
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* In the async case this is being triggered with the
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* device lock held and the unregistration work needs to
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* be moved out of line iff this is thread has won the
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* race to schedule the deletion.
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*/
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if (!kill_device(dev))
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return;
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get_device(dev);
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async_schedule_domain(nd_async_device_unregister, dev,
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&nd_async_domain);
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break;
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case ND_SYNC:
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/*
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* In the sync case the device is being unregistered due
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* to a state change of the parent. Claim the kill state
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* to synchronize against other unregistration requests,
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* or otherwise let the async path handle it if the
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* unregistration was already queued.
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*/
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device_lock(dev);
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killed = kill_device(dev);
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device_unlock(dev);
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if (!killed)
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return;
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nd_synchronize();
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device_unregister(dev);
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break;
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