linux-stable/drivers/nvdimm
Dan Williams ca6bf264f6 libnvdimm/bus: Fix wait_nvdimm_bus_probe_idle() ABBA deadlock
A multithreaded namespace creation/destruction stress test currently
deadlocks with the following lockup signature:

    INFO: task ndctl:2924 blocked for more than 122 seconds.
          Tainted: G           OE     5.2.0-rc4+ #3382
    "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
    ndctl           D    0  2924   1176 0x00000000
    Call Trace:
     ? __schedule+0x27e/0x780
     schedule+0x30/0xb0
     wait_nvdimm_bus_probe_idle+0x8a/0xd0 [libnvdimm]
     ? finish_wait+0x80/0x80
     uuid_store+0xe6/0x2e0 [libnvdimm]
     kernfs_fop_write+0xf0/0x1a0
     vfs_write+0xb7/0x1b0
     ksys_write+0x5c/0xd0
     do_syscall_64+0x60/0x240

     INFO: task ndctl:2923 blocked for more than 122 seconds.
           Tainted: G           OE     5.2.0-rc4+ #3382
     "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
     ndctl           D    0  2923   1175 0x00000000
     Call Trace:
      ? __schedule+0x27e/0x780
      ? __mutex_lock+0x489/0x910
      schedule+0x30/0xb0
      schedule_preempt_disabled+0x11/0x20
      __mutex_lock+0x48e/0x910
      ? nvdimm_namespace_common_probe+0x95/0x4d0 [libnvdimm]
      ? __lock_acquire+0x23f/0x1710
      ? nvdimm_namespace_common_probe+0x95/0x4d0 [libnvdimm]
      nvdimm_namespace_common_probe+0x95/0x4d0 [libnvdimm]
      __dax_pmem_probe+0x5e/0x210 [dax_pmem_core]
      ? nvdimm_bus_probe+0x1d0/0x2c0 [libnvdimm]
      dax_pmem_probe+0xc/0x20 [dax_pmem]
      nvdimm_bus_probe+0x90/0x2c0 [libnvdimm]
      really_probe+0xef/0x390
      driver_probe_device+0xb4/0x100

In this sequence an 'nd_dax' device is being probed and trying to take
the lock on its backing namespace to validate that the 'nd_dax' device
indeed has exclusive access to the backing namespace. Meanwhile, another
thread is trying to update the uuid property of that same backing
namespace. So one thread is in the probe path trying to acquire the
lock, and the other thread has acquired the lock and tries to flush the
probe path.

Fix this deadlock by not holding the namespace device_lock over the
wait_nvdimm_bus_probe_idle() synchronization step. In turn this requires
the device_lock to be held on entry to wait_nvdimm_bus_probe_idle() and
subsequently dropped internally to wait_nvdimm_bus_probe_idle().

Cc: <stable@vger.kernel.org>
Fixes: bf9bccc14c ("libnvdimm: pmem label sets and namespace instantiation")
Cc: Vishal Verma <vishal.l.verma@intel.com>
Tested-by: Jane Chu <jane.chu@oracle.com>
Link: https://lore.kernel.org/r/156341210094.292348.2384694131126767789.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2019-07-18 16:23:16 -07:00
..
badrange.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295 2019-06-05 17:36:38 +02:00
blk.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 288 2019-06-05 17:36:37 +02:00
btt.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 288 2019-06-05 17:36:37 +02:00
btt.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 288 2019-06-05 17:36:37 +02:00
btt_devs.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295 2019-06-05 17:36:38 +02:00
bus.c libnvdimm/bus: Fix wait_nvdimm_bus_probe_idle() ABBA deadlock 2019-07-18 16:23:16 -07:00
claim.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295 2019-06-05 17:36:38 +02:00
core.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295 2019-06-05 17:36:38 +02:00
dax_devs.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295 2019-06-05 17:36:38 +02:00
dimm.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295 2019-06-05 17:36:38 +02:00
dimm_devs.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295 2019-06-05 17:36:38 +02:00
e820.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
Kconfig treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
label.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295 2019-06-05 17:36:38 +02:00
label.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295 2019-06-05 17:36:38 +02:00
Makefile acpi/nfit, libnvdimm: Add unlock of nvdimm support for Intel DIMMs 2018-12-13 17:54:13 -08:00
namespace_devs.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295 2019-06-05 17:36:38 +02:00
nd-core.h libnvdimm/bus: Stop holding nvdimm_bus_list_mutex over __nd_ioctl() 2019-07-18 16:23:02 -07:00
nd.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295 2019-06-05 17:36:38 +02:00
of_pmem.c device-dax for 5.1 2019-03-16 13:05:32 -07:00
pfn.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 288 2019-06-05 17:36:37 +02:00
pfn_devs.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295 2019-06-05 17:36:38 +02:00
pmem.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 288 2019-06-05 17:36:37 +02:00
pmem.h libnvdimm, pmem: Restore page attributes when clearing errors 2018-08-20 09:22:45 -07:00
region.c libnvdimm/region: Register badblocks before namespaces 2019-07-18 16:22:19 -07:00
region_devs.c libnvdimm/bus: Fix wait_nvdimm_bus_probe_idle() ABBA deadlock 2019-07-18 16:23:16 -07:00
security.c libnvdimm/security, acpi/nfit: unify zero-key for all security commands 2019-03-30 08:27:07 -07:00