linux/tools
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
..
accounting
arch Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-06-02 11:08:12 -07:00
bpf SPDX update for 5.2-rc2, round 1 2019-05-21 12:33:38 -07:00
build treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
cgroup
crypto
debugging tools: add a kernel-chktaint to tools/debugging 2019-01-08 16:29:52 -07:00
firewire treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
firmware tools/firmware/ihex2fw: Replace explicit alignment with ALIGN 2019-01-22 10:23:18 +01:00
gpio tools gpio: Allow overriding CFLAGS 2018-12-28 16:33:08 -03:00
hv treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 280 2019-06-05 17:36:36 +02:00
iio Merge 5.0-rc6 into staging-next 2019-02-11 09:25:01 +01:00
include Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-06-02 11:08:12 -07:00
io_uring tools/io_uring: sync with liburing 2019-05-23 10:25:26 -06:00
kvm/kvm_stat tools/kvm_stat: fix fields filter for child events 2019-05-24 21:27:17 +02:00
laptop
leds
lib treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 251 2019-06-05 17:30:26 +02:00
memory-model tools/memory-model: Add support for synchronize_srcu_expedited() 2019-04-04 13:48:34 -07:00
nfsd
objtool treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
pci treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 341 2019-06-05 17:37:07 +02:00
pcmcia
perf treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
power treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
scripts
spi treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 178 2019-05-30 11:29:19 -07:00
testing mm/devm_memremap_pages: fix final page put race 2019-06-13 17:34:56 -10:00
thermal/tmon treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 89 2019-05-24 17:37:52 +02:00
time treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 282 2019-06-05 17:36:37 +02:00
usb treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
virtio virtio: fixes 2019-06-03 10:04:05 -07:00
vm treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 282 2019-06-05 17:36:37 +02:00
wmi treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Makefile Merge branch 'thorsten' into docs-next 2019-01-08 16:38:36 -07:00