kernel/drivers/nvdimm, branch linux-5.2.y

libnvdimm/bus: Fix wait_nvdimm_bus_probe_idle() ABBA deadlock

2019-08-09T15:51:41Z

commit ca6bf264f6d856f959c4239cda1047b587745c67 upstream. 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: Fixes: bf9bccc14c05 ("libnvdimm: pmem label sets and namespace instantiation") Cc: Vishal Verma Tested-by: Jane Chu Link: https://lore.kernel.org/r/156341210094.292348.2384694131126767789.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams Signed-off-by: Sasha Levin

libnvdimm/bus: Prepare the nd_ioctl() path to be re-entrant

2019-08-09T15:51:41Z

commit 6de5d06e657acdbcf9637dac37916a4a5309e0f4 upstream. In preparation for not holding a lock over the execution of nd_ioctl(), update the implementation to allow multiple threads to be attempting ioctls at the same time. The bus lock still prevents multiple in-flight ->ndctl() invocations from corrupting each other's state, but static global staging buffers are moved to the heap. Reported-by: Vishal Verma Reviewed-by: Vishal Verma Tested-by: Vishal Verma Link: https://lore.kernel.org/r/156341208947.292348.10560140326807607481.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams Signed-off-by: Sasha Levin

libnvdimm/bus: Stop holding nvdimm_bus_list_mutex over __nd_ioctl()

2019-07-31T05:25:02Z

commit b70d31d054ee3a6fc1034b9d7fc0ae1e481aa018 upstream. In preparation for fixing a deadlock between wait_for_bus_probe_idle() and the nvdimm_bus_list_mutex arrange for __nd_ioctl() without nvdimm_bus_list_mutex held. This also unifies the 'dimm' and 'bus' level ioctls into a common nd_ioctl() preamble implementation. Marked for -stable as it is a pre-requisite for a follow-on fix. Cc: Fixes: bf9bccc14c05 ("libnvdimm: pmem label sets and namespace instantiation") Cc: Vishal Verma Tested-by: Jane Chu Link: https://lore.kernel.org/r/156341209518.292348.7183897251740665198.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams Signed-off-by: Greg Kroah-Hartman

libnvdimm/region: Register badblocks before namespaces

2019-07-31T05:25:02Z

commit 700cd033a82d466ad8f9615f9985525e45f8960a upstream. Namespace activation expects to be able to reference region badblocks. The following warning sometimes triggers when asynchronous namespace activation races in front of the completion of namespace probing. Move all possible namespace probing after region badblocks initialization. Otherwise, lockdep sometimes catches the uninitialized state of the badblocks seqlock with stack trace signatures like: INFO: trying to register non-static key. pmem2: detected capacity change from 0 to 136365211648 the code is fine but needs lockdep annotation. turning off the locking correctness validator. CPU: 9 PID: 358 Comm: kworker/u80:5 Tainted: G OE 5.2.0-rc4+ #3382 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015 Workqueue: events_unbound async_run_entry_fn Call Trace: dump_stack+0x85/0xc0 pmem1.12: detected capacity change from 0 to 8589934592 register_lock_class+0x56a/0x570 ? check_object+0x140/0x270 __lock_acquire+0x80/0x1710 ? __mutex_lock+0x39d/0x910 lock_acquire+0x9e/0x180 ? nd_pfn_validate+0x28f/0x440 [libnvdimm] badblocks_check+0x93/0x1f0 ? nd_pfn_validate+0x28f/0x440 [libnvdimm] nd_pfn_validate+0x28f/0x440 [libnvdimm] ? lockdep_hardirqs_on+0xf0/0x180 nd_dax_probe+0x9a/0x120 [libnvdimm] nd_pmem_probe+0x6d/0x180 [nd_pmem] nvdimm_bus_probe+0x90/0x2c0 [libnvdimm] Fixes: 48af2f7e52f4 ("libnvdimm, pfn: during init, clear errors...") Cc: Cc: Vishal Verma Reviewed-by: Vishal Verma Link: https://lore.kernel.org/r/156341208365.292348.1547528796026249120.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams Signed-off-by: Greg Kroah-Hartman

libnvdimm/bus: Prevent duplicate device_unregister() calls

2019-07-31T05:25:02Z

commit 8aac0e2338916e273ccbd438a2b7a1e8c61749f5 upstream. A multithreaded namespace creation/destruction stress test currently fails with signatures like the following: sysfs group 'power' not found for kobject 'dax1.1' RIP: 0010:sysfs_remove_group+0x76/0x80 Call Trace: device_del+0x73/0x370 device_unregister+0x16/0x50 nd_async_device_unregister+0x1e/0x30 [libnvdimm] async_run_entry_fn+0x39/0x160 process_one_work+0x23c/0x5e0 worker_thread+0x3c/0x390 BUG: kernel NULL pointer dereference, address: 0000000000000020 RIP: 0010:klist_put+0x1b/0x6c Call Trace: klist_del+0xe/0x10 device_del+0x8a/0x2c9 ? __switch_to_asm+0x34/0x70 ? __switch_to_asm+0x40/0x70 device_unregister+0x44/0x4f nd_async_device_unregister+0x22/0x2d [libnvdimm] async_run_entry_fn+0x47/0x15a process_one_work+0x1a2/0x2eb worker_thread+0x1b8/0x26e Use the kill_device() helper to atomically resolve the race of multiple threads issuing kill, device_unregister(), requests. Reported-by: Jane Chu Reported-by: Erwin Tsaur Fixes: 4d88a97aa9e8 ("libnvdimm, nvdimm: dimm driver and base libnvdimm device-driver...") Cc: Link: https://github.com/pmem/ndctl/issues/96 Tested-by: Tested-by: Jane Chu Link: https://lore.kernel.org/r/156341207846.292348.10435719262819764054.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams Signed-off-by: Greg Kroah-Hartman

libnvdimm/pfn: fix fsdax-mode namespace info-block zero-fields

2019-07-26T07:11:06Z

commit 7e3e888dfc138089f4c15a81b418e88f0978f744 upstream. At namespace creation time there is the potential for the "expected to be zero" fields of a 'pfn' info-block to be filled with indeterminate data. While the kernel buffer is zeroed on allocation it is immediately overwritten by nd_pfn_validate() filling it with the current contents of the on-media info-block location. For fields like, 'flags' and the 'padding' it potentially means that future implementations can not rely on those fields being zero. In preparation to stop using the 'start_pad' and 'end_trunc' fields for section alignment, arrange for fields that are not explicitly initialized to be guaranteed zero. Bump the minor version to indicate it is safe to assume the 'padding' and 'flags' are zero. Otherwise, this corruption is expected to benign since all other critical fields are explicitly initialized. Note The cc: stable is about spreading this new policy to as many kernels as possible not fixing an issue in those kernels. It is not until the change titled "libnvdimm/pfn: Stop padding pmem namespaces to section alignment" where this improper initialization becomes a problem. So if someone decides to backport "libnvdimm/pfn: Stop padding pmem namespaces to section alignment" (which is not tagged for stable), make sure this pre-requisite is flagged. Link: http://lkml.kernel.org/r/156092356065.979959.6681003754765958296.stgit@dwillia2-desk3.amr.corp.intel.com Fixes: 32ab0a3f5170 ("libnvdimm, pmem: 'struct page' for pmem") Signed-off-by: Dan Williams Tested-by: Aneesh Kumar K.V [ppc64] Cc: Cc: David Hildenbrand Cc: Jane Chu Cc: Jeff Moyer Cc: Jérôme Glisse Cc: Jonathan Corbet Cc: Logan Gunthorpe Cc: Michal Hocko Cc: Mike Rapoport Cc: Oscar Salvador Cc: Pavel Tatashin Cc: Toshi Kani Cc: Vlastimil Babka Cc: Wei Yang Cc: Jason Gunthorpe Cc: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm/devm_memremap_pages: fix final page put race

2019-06-14T03:34:56Z

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: 41e94a851304 ("add devm_memremap_pages") Signed-off-by: Dan Williams Reported-by: Logan Gunthorpe Reviewed-by: Ira Weiny Reviewed-by: Logan Gunthorpe Cc: Bjorn Helgaas Cc: "Jérôme Glisse" Cc: Christoph Hellwig Cc: Greg Kroah-Hartman Cc: "Rafael J. Wysocki" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295

2019-06-05T15:36:38Z

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of version 2 of the gnu general public license as published by the free software foundation this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 64 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Alexios Zavras Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190529141901.894819585@linutronix.de Signed-off-by: Greg Kroah-Hartman

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 288

2019-06-05T15:36:37Z

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms and conditions of the gnu general public license version 2 as published by the free software foundation this program is distributed in the hope it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 263 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Reviewed-by: Alexios Zavras Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190529141901.208660670@linutronix.de Signed-off-by: Greg Kroah-Hartman

Merge tag 'libnvdimm-fixes-5.2-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

2019-05-25T17:11:23Z

Pull libnvdimm fixes from Dan Williams: - Fix a regression that disabled device-mapper dax support - Remove unnecessary hardened-user-copy overhead (>30%) for dax read(2)/write(2). - Fix some compilation warnings. * tag 'libnvdimm-fixes-5.2-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: libnvdimm/pmem: Bypass CONFIG_HARDENED_USERCOPY overhead dax: Arrange for dax_supported check to span multiple devices libnvdimm: Fix compilation warnings with W=1