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| author | Dan Williams <dan.j.williams@intel.com> | 2017-04-28 22:05:14 -0700 |
|---|---|---|
| committer | Dan Williams <dan.j.williams@intel.com> | 2017-05-01 08:29:37 -0700 |
| commit | 452bae0aede774f87bf56c28b6dd50b72c78986c (patch) | |
| tree | f577780c5431059b334ae019ec8e3e8c6a652797 /drivers/nvdimm/claim.c | |
| parent | 23f4984483623cf8621246004228f08fcabf51e4 (diff) | |
| download | linux-452bae0aede774f87bf56c28b6dd50b72c78986c.tar.bz2 | |
libnvdimm: fix nvdimm_bus_lock() vs device_lock() ordering
A debug patch to turn the standard device_lock() into something that
lockdep can analyze yielded the following:
======================================================
[ INFO: possible circular locking dependency detected ]
4.11.0-rc4+ #106 Tainted: G O
-------------------------------------------------------
lt-libndctl/1898 is trying to acquire lock:
(&dev->nvdimm_mutex/3){+.+.+.}, at: [<ffffffffc023c948>] nd_attach_ndns+0x178/0x1b0 [libnvdimm]
but task is already holding lock:
(&nvdimm_bus->reconfig_mutex){+.+.+.}, at: [<ffffffffc022e0b1>] nvdimm_bus_lock+0x21/0x30 [libnvdimm]
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&nvdimm_bus->reconfig_mutex){+.+.+.}:
lock_acquire+0xf6/0x1f0
__mutex_lock+0x88/0x980
mutex_lock_nested+0x1b/0x20
nvdimm_bus_lock+0x21/0x30 [libnvdimm]
nvdimm_namespace_capacity+0x1b/0x40 [libnvdimm]
nvdimm_namespace_common_probe+0x230/0x510 [libnvdimm]
nd_pmem_probe+0x14/0x180 [nd_pmem]
nvdimm_bus_probe+0xa9/0x260 [libnvdimm]
-> #0 (&dev->nvdimm_mutex/3){+.+.+.}:
__lock_acquire+0x1107/0x1280
lock_acquire+0xf6/0x1f0
__mutex_lock+0x88/0x980
mutex_lock_nested+0x1b/0x20
nd_attach_ndns+0x178/0x1b0 [libnvdimm]
nd_namespace_store+0x308/0x3c0 [libnvdimm]
namespace_store+0x87/0x220 [libnvdimm]
In this case '&dev->nvdimm_mutex/3' mirrors '&dev->mutex'.
Fix this by replacing the use of device_lock() with nvdimm_bus_lock() to protect
nd_{attach,detach}_ndns() operations.
Cc: <stable@vger.kernel.org>
Fixes: 8c2f7e8658df ("libnvdimm: infrastructure for btt devices")
Reported-by: Yi Zhang <yizhan@redhat.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/nvdimm/claim.c')
| -rw-r--r-- | drivers/nvdimm/claim.c | 23 |
1 files changed, 15 insertions, 8 deletions
diff --git a/drivers/nvdimm/claim.c b/drivers/nvdimm/claim.c index 2c19bc7fc056..35b210dc1e56 100644 --- a/drivers/nvdimm/claim.c +++ b/drivers/nvdimm/claim.c @@ -21,8 +21,13 @@ void __nd_detach_ndns(struct device *dev, struct nd_namespace_common **_ndns) { struct nd_namespace_common *ndns = *_ndns; + struct nvdimm_bus *nvdimm_bus; - lockdep_assert_held(&ndns->dev.mutex); + if (!ndns) + return; + + nvdimm_bus = walk_to_nvdimm_bus(&ndns->dev); + lockdep_assert_held(&nvdimm_bus->reconfig_mutex); dev_WARN_ONCE(dev, ndns->claim != dev, "%s: invalid claim\n", __func__); ndns->claim = NULL; *_ndns = NULL; @@ -37,18 +42,20 @@ void nd_detach_ndns(struct device *dev, if (!ndns) return; get_device(&ndns->dev); - device_lock(&ndns->dev); + nvdimm_bus_lock(&ndns->dev); __nd_detach_ndns(dev, _ndns); - device_unlock(&ndns->dev); + nvdimm_bus_unlock(&ndns->dev); put_device(&ndns->dev); } bool __nd_attach_ndns(struct device *dev, struct nd_namespace_common *attach, struct nd_namespace_common **_ndns) { + struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(&attach->dev); + if (attach->claim) return false; - lockdep_assert_held(&attach->dev.mutex); + lockdep_assert_held(&nvdimm_bus->reconfig_mutex); dev_WARN_ONCE(dev, *_ndns, "%s: invalid claim\n", __func__); attach->claim = dev; *_ndns = attach; @@ -61,9 +68,9 @@ bool nd_attach_ndns(struct device *dev, struct nd_namespace_common *attach, { bool claimed; - device_lock(&attach->dev); + nvdimm_bus_lock(&attach->dev); claimed = __nd_attach_ndns(dev, attach, _ndns); - device_unlock(&attach->dev); + nvdimm_bus_unlock(&attach->dev); return claimed; } @@ -114,7 +121,7 @@ static void nd_detach_and_reset(struct device *dev, struct nd_namespace_common **_ndns) { /* detach the namespace and destroy / reset the device */ - nd_detach_ndns(dev, _ndns); + __nd_detach_ndns(dev, _ndns); if (is_idle(dev, *_ndns)) { nd_device_unregister(dev, ND_ASYNC); } else if (is_nd_btt(dev)) { @@ -184,7 +191,7 @@ ssize_t nd_namespace_store(struct device *dev, } WARN_ON_ONCE(!is_nvdimm_bus_locked(dev)); - if (!nd_attach_ndns(dev, ndns, _ndns)) { + if (!__nd_attach_ndns(dev, ndns, _ndns)) { dev_dbg(dev, "%s already claimed\n", dev_name(&ndns->dev)); len = -EBUSY; |