mirror of
https://github.com/Ysurac/openmptcprouter.git
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96 lines
3 KiB
Diff
96 lines
3 KiB
Diff
From d16bbdbbcb5002c5366cbf6402561d0350afd5fe Mon Sep 17 00:00:00 2001
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From: Dan Williams <dan.j.williams@intel.com>
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Date: Mon, 5 Aug 2019 18:31:56 -0700
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Subject: [PATCH 772/826] libnvdimm/bus: Prevent duplicate device_unregister()
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calls
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commit 8aac0e2338916e273ccbd438a2b7a1e8c61749f5 upstream.
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A multithreaded namespace creation/destruction stress test currently
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fails with signatures like the following:
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sysfs group 'power' not found for kobject 'dax1.1'
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RIP: 0010:sysfs_remove_group+0x76/0x80
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Call Trace:
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device_del+0x73/0x370
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device_unregister+0x16/0x50
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nd_async_device_unregister+0x1e/0x30 [libnvdimm]
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async_run_entry_fn+0x39/0x160
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process_one_work+0x23c/0x5e0
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worker_thread+0x3c/0x390
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BUG: kernel NULL pointer dereference, address: 0000000000000020
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RIP: 0010:klist_put+0x1b/0x6c
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Call Trace:
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klist_del+0xe/0x10
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device_del+0x8a/0x2c9
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? __switch_to_asm+0x34/0x70
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? __switch_to_asm+0x40/0x70
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device_unregister+0x44/0x4f
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nd_async_device_unregister+0x22/0x2d [libnvdimm]
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async_run_entry_fn+0x47/0x15a
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process_one_work+0x1a2/0x2eb
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worker_thread+0x1b8/0x26e
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Use the kill_device() helper to atomically resolve the race of multiple
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threads issuing kill, device_unregister(), requests.
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Reported-by: Jane Chu <jane.chu@oracle.com>
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Reported-by: Erwin Tsaur <erwin.tsaur@oracle.com>
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Fixes: 4d88a97aa9e8 ("libnvdimm, nvdimm: dimm driver and base libnvdimm device-driver...")
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Cc: <stable@vger.kernel.org>
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Link: https://github.com/pmem/ndctl/issues/96
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Tested-by: Tested-by: Jane Chu <jane.chu@oracle.com>
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Link: https://lore.kernel.org/r/156341207846.292348.10435719262819764054.stgit@dwillia2-desk3.amr.corp.intel.com
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Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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Signed-off-by: Sasha Levin <sashal@kernel.org>
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---
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drivers/nvdimm/bus.c | 25 +++++++++++++++++++++++++
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1 file changed, 25 insertions(+)
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diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
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index ee39e2c1644a..11cfd23e5aff 100644
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--- a/drivers/nvdimm/bus.c
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+++ b/drivers/nvdimm/bus.c
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@@ -528,13 +528,38 @@ 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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+
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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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+
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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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+
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+ if (!killed)
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+ return;
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+
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nd_synchronize();
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device_unregister(dev);
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break;
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--
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2.22.0
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