linux/tools/testing/nvdimm
Dan Williams 50f44ee724 mm/devm_memremap_pages: fix final page put race
Logan noticed that devm_memremap_pages_release() kills the percpu_ref
drops all the page references that were acquired at init and then
immediately proceeds to unplug, arch_remove_memory(), the backing pages
for the pagemap.  If for some reason device shutdown actually collides
with a busy / elevated-ref-count page then arch_remove_memory() should
be deferred until after that reference is dropped.

As it stands the "wait for last page ref drop" happens *after*
devm_memremap_pages_release() returns, which is obviously too late and
can lead to crashes.

Fix this situation by assigning the responsibility to wait for the
percpu_ref to go idle to devm_memremap_pages() with a new ->cleanup()
callback.  Implement the new cleanup callback for all
devm_memremap_pages() users: pmem, devdax, hmm, and p2pdma.

Link: http://lkml.kernel.org/r/155727339156.292046.5432007428235387859.stgit@dwillia2-desk3.amr.corp.intel.com
Fixes: 41e94a8513 ("add devm_memremap_pages")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-06-13 17:34:56 -10:00
..
test mm/devm_memremap_pages: fix final page put race 2019-06-13 17:34:56 -10:00
acpi_nfit_test.c tools/testing/nvdimm: Populate dirty shutdown data 2018-10-17 10:47:19 -07:00
config_check.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dax_pmem_compat_test.c tools/testing/nvdimm: add watermarks for dax_pmem* modules 2019-04-22 15:56:28 -07:00
dax_pmem_core_test.c tools/testing/nvdimm: add watermarks for dax_pmem* modules 2019-04-22 15:56:28 -07:00
dax_pmem_test.c tools/testing/nvdimm: add watermarks for dax_pmem* modules 2019-04-22 15:56:28 -07:00
dax-dev.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 288 2019-06-05 17:36:37 +02:00
device_dax_test.c tools/testing/nvdimm: force nfit_test to depend on instrumented modules 2018-02-01 16:49:54 -08:00
dimm_devs.c nfit_test: fix security state pull for nvdimm security nfit_test 2019-01-21 09:56:29 -08:00
Kbuild tools/testing/nvdimm: add watermarks for dax_pmem* modules 2019-04-22 15:56:28 -07:00
libnvdimm_test.c tools/testing/nvdimm: force nfit_test to depend on instrumented modules 2018-02-01 16:49:54 -08:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pmem_test.c tools/testing/nvdimm: force nfit_test to depend on instrumented modules 2018-02-01 16:49:54 -08:00
pmem-dax.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 288 2019-06-05 17:36:37 +02:00
watermark.h tools/testing/nvdimm: add watermarks for dax_pmem* modules 2019-04-22 15:56:28 -07:00