user/sven/linux.git/kernel/memremap.c, branch v4.19.207

mm/memory_hotplug: shrink zones when offlining memory

2020-01-29T15:43:27Z

commit feee6b2989165631b17ac6d4ccdbf6759254e85a upstream. -- snip -- - Missing arm64 hot(un)plug support - Missing some vmem_altmap_offset() cleanups - Missing sub-section hotadd support - Missing unification of mm/hmm.c and kernel/memremap.c -- snip -- We currently try to shrink a single zone when removing memory. We use the zone of the first page of the memory we are removing. If that memmap was never initialized (e.g., memory was never onlined), we will read garbage and can trigger kernel BUGs (due to a stale pointer): BUG: unable to handle page fault for address: 000000000000353d #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP PTI CPU: 1 PID: 7 Comm: kworker/u8:0 Not tainted 5.3.0-rc5-next-20190820+ #317 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.4 Workqueue: kacpi_hotplug acpi_hotplug_work_fn RIP: 0010:clear_zone_contiguous+0x5/0x10 Code: 48 89 c6 48 89 c3 e8 2a fe ff ff 48 85 c0 75 cf 5b 5d c3 c6 85 fd 05 00 00 01 5b 5d c3 0f 1f 840 RSP: 0018:ffffad2400043c98 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000200000000 RCX: 0000000000000000 RDX: 0000000000200000 RSI: 0000000000140000 RDI: 0000000000002f40 RBP: 0000000140000000 R08: 0000000000000000 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000140000 R13: 0000000000140000 R14: 0000000000002f40 R15: ffff9e3e7aff3680 FS: 0000000000000000(0000) GS:ffff9e3e7bb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000000353d CR3: 0000000058610000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __remove_pages+0x4b/0x640 arch_remove_memory+0x63/0x8d try_remove_memory+0xdb/0x130 __remove_memory+0xa/0x11 acpi_memory_device_remove+0x70/0x100 acpi_bus_trim+0x55/0x90 acpi_device_hotplug+0x227/0x3a0 acpi_hotplug_work_fn+0x1a/0x30 process_one_work+0x221/0x550 worker_thread+0x50/0x3b0 kthread+0x105/0x140 ret_from_fork+0x3a/0x50 Modules linked in: CR2: 000000000000353d Instead, shrink the zones when offlining memory or when onlining failed. Introduce and use remove_pfn_range_from_zone(() for that. We now properly shrink the zones, even if we have DIMMs whereby - Some memory blocks fall into no zone (never onlined) - Some memory blocks fall into multiple zones (offlined+re-onlined) - Multiple memory blocks that fall into different zones Drop the zone parameter (with a potential dubious value) from __remove_pages() and __remove_section(). Link: http://lkml.kernel.org/r/20191006085646.5768-6-david@redhat.com Fixes: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online") [visible after d0dc12e86b319] Signed-off-by: David Hildenbrand Reviewed-by: Oscar Salvador Cc: Michal Hocko Cc: "Matthew Wilcox (Oracle)" Cc: "Aneesh Kumar K.V" Cc: Pavel Tatashin Cc: Greg Kroah-Hartman Cc: Dan Williams Cc: Logan Gunthorpe Cc: [5.0+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: David Hildenbrand Signed-off-by: Greg Kroah-Hartman

mm/memunmap: don't access uninitialized memmap in memunmap_pages()

2020-01-29T15:43:27Z

commit 77e080e7680e1e615587352f70c87b9e98126d03 upstream. -- snip -- - Missing mm/hmm.c and kernel/memremap.c unification. -- hmm code does not need fixes (no altmap) - Missing 7cc7867fb061 ("mm/devm_memremap_pages: enable sub-section remap") -- snip -- Patch series "mm/memory_hotplug: Shrink zones before removing memory", v6. This series fixes the access of uninitialized memmaps when shrinking zones/nodes and when removing memory. Also, it contains all fixes for crashes that can be triggered when removing certain namespace using memunmap_pages() - ZONE_DEVICE, reported by Aneesh. We stop trying to shrink ZONE_DEVICE, as it's buggy, fixing it would be more involved (we don't have SECTION_IS_ONLINE as an indicator), and shrinking is only of limited use (set_zone_contiguous() cannot detect the ZONE_DEVICE as contiguous). We continue shrinking !ZONE_DEVICE zones, however, I reduced the amount of code to a minimum. Shrinking is especially necessary to keep zone->contiguous set where possible, especially, on memory unplug of DIMMs at zone boundaries. -------------------------------------------------------------------------- Zones are now properly shrunk when offlining memory blocks or when onlining failed. This allows to properly shrink zones on memory unplug even if the separate memory blocks of a DIMM were onlined to different zones or re-onlined to a different zone after offlining. Example: :/# cat /proc/zoneinfo Node 1, zone Movable spanned 0 present 0 managed 0 :/# echo "online_movable" > /sys/devices/system/memory/memory41/state :/# echo "online_movable" > /sys/devices/system/memory/memory43/state :/# cat /proc/zoneinfo Node 1, zone Movable spanned 98304 present 65536 managed 65536 :/# echo 0 > /sys/devices/system/memory/memory43/online :/# cat /proc/zoneinfo Node 1, zone Movable spanned 32768 present 32768 managed 32768 :/# echo 0 > /sys/devices/system/memory/memory41/online :/# cat /proc/zoneinfo Node 1, zone Movable spanned 0 present 0 managed 0 This patch (of 10): With an altmap, the memmap falling into the reserved altmap space are not initialized and, therefore, contain a garbage NID and a garbage zone. Make sure to read the NID/zone from a memmap that was initialized. This fixes a kernel crash that is observed when destroying a namespace: kernel BUG at include/linux/mm.h:1107! cpu 0x1: Vector: 700 (Program Check) at [c000000274087890] pc: c0000000004b9728: memunmap_pages+0x238/0x340 lr: c0000000004b9724: memunmap_pages+0x234/0x340 ... pid = 3669, comm = ndctl kernel BUG at include/linux/mm.h:1107! devm_action_release+0x30/0x50 release_nodes+0x268/0x2d0 device_release_driver_internal+0x174/0x240 unbind_store+0x13c/0x190 drv_attr_store+0x44/0x60 sysfs_kf_write+0x70/0xa0 kernfs_fop_write+0x1ac/0x290 __vfs_write+0x3c/0x70 vfs_write+0xe4/0x200 ksys_write+0x7c/0x140 system_call+0x5c/0x68 The "page_zone(pfn_to_page(pfn)" was introduced by 69324b8f4833 ("mm, devm_memremap_pages: add MEMORY_DEVICE_PRIVATE support"), however, I think we will never have driver reserved memory with MEMORY_DEVICE_PRIVATE (no altmap AFAIKS). [david@redhat.com: minimze code changes, rephrase description] Link: http://lkml.kernel.org/r/20191006085646.5768-2-david@redhat.com Fixes: 2c2a5af6fed2 ("mm, memory_hotplug: add nid parameter to arch_remove_memory") Signed-off-by: Aneesh Kumar K.V Signed-off-by: David Hildenbrand Cc: Dan Williams Cc: Jason Gunthorpe Cc: Logan Gunthorpe Cc: Ira Weiny Cc: Damian Tometzki Cc: Alexander Duyck Cc: Alexander Potapenko Cc: Andy Lutomirski Cc: Anshuman Khandual Cc: Benjamin Herrenschmidt Cc: Borislav Petkov Cc: Catalin Marinas Cc: Christian Borntraeger Cc: Christophe Leroy Cc: Dave Hansen Cc: Fenghua Yu Cc: Gerald Schaefer Cc: Greg Kroah-Hartman Cc: Halil Pasic Cc: Heiko Carstens Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Jun Yao Cc: Mark Rutland Cc: Masahiro Yamada Cc: "Matthew Wilcox (Oracle)" Cc: Mel Gorman Cc: Michael Ellerman Cc: Michal Hocko Cc: Mike Rapoport Cc: Oscar Salvador Cc: Pankaj Gupta Cc: Paul Mackerras Cc: Pavel Tatashin Cc: Pavel Tatashin Cc: Peter Zijlstra Cc: Qian Cai Cc: Rich Felker Cc: Robin Murphy Cc: Steve Capper Cc: Thomas Gleixner Cc: Tom Lendacky Cc: Tony Luck Cc: Vasily Gorbik Cc: Vlastimil Babka Cc: Wei Yang Cc: Wei Yang Cc: Will Deacon Cc: Yoshinori Sato Cc: Yu Zhao Cc: [5.0+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: David Hildenbrand Signed-off-by: Greg Kroah-Hartman

mm, memory_hotplug: add nid parameter to arch_remove_memory

2020-01-29T15:43:25Z

commit 2c2a5af6fed20cf74401c9d64319c76c5ff81309 upstream. -- snip -- Missing unification of mm/hmm.c and kernel/memremap.c -- snip -- Patch series "Do not touch pages in hot-remove path", v2. This patchset aims for two things: 1) A better definition about offline and hot-remove stage 2) Solving bugs where we can access non-initialized pages during hot-remove operations [2] [3]. This is achieved by moving all page/zone handling to the offline stage, so we do not need to access pages when hot-removing memory. [1] https://patchwork.kernel.org/cover/10691415/ [2] https://patchwork.kernel.org/patch/10547445/ [3] https://www.spinics.net/lists/linux-mm/msg161316.html This patch (of 5): This is a preparation for the following-up patches. The idea of passing the nid is that it will allow us to get rid of the zone parameter afterwards. Link: http://lkml.kernel.org/r/20181127162005.15833-2-osalvador@suse.de Signed-off-by: Oscar Salvador Reviewed-by: David Hildenbrand Reviewed-by: Pavel Tatashin Cc: Michal Hocko Cc: Dan Williams Cc: Jerome Glisse Cc: Jonathan Cameron Cc: "Rafael J. Wysocki" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: David Hildenbrand Signed-off-by: Greg Kroah-Hartman

mm, devm_memremap_pages: add MEMORY_DEVICE_PRIVATE support

2019-01-13T08:51:04Z

commit 69324b8f48339de2f90fdf2f774687fc6c47629a upstream. In preparation for consolidating all ZONE_DEVICE enabling via devm_memremap_pages(), teach it how to handle the constraints of MEMORY_DEVICE_PRIVATE ranges. [jglisse@redhat.com: call move_pfn_range_to_zone for MEMORY_DEVICE_PRIVATE] Link: http://lkml.kernel.org/r/154275559036.76910.12434636179931292607.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams Reviewed-by: Jérôme Glisse Acked-by: Christoph Hellwig Reported-by: Logan Gunthorpe Reviewed-by: Logan Gunthorpe Cc: Balbir Singh Cc: Michal Hocko Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm, devm_memremap_pages: fix shutdown handling

2019-01-13T08:51:04Z

commit a95c90f1e2c253b280385ecf3d4ebfe476926b28 upstream. The last step before devm_memremap_pages() returns success is to allocate a release action, devm_memremap_pages_release(), to tear the entire setup down. However, the result from devm_add_action() is not checked. Checking the error from devm_add_action() is not enough. The api currently relies on the fact that the percpu_ref it is using is killed by the time the devm_memremap_pages_release() is run. Rather than continue this awkward situation, offload the responsibility of killing the percpu_ref to devm_memremap_pages_release() directly. This allows devm_memremap_pages() to do the right thing relative to init failures and shutdown. Without this change we could fail to register the teardown of devm_memremap_pages(). The likelihood of hitting this failure is tiny as small memory allocations almost always succeed. However, the impact of the failure is large given any future reconfiguration, or disable/enable, of an nvdimm namespace will fail forever as subsequent calls to devm_memremap_pages() will fail to setup the pgmap_radix since there will be stale entries for the physical address range. An argument could be made to require that the ->kill() operation be set in the @pgmap arg rather than passed in separately. However, it helps code readability, tracking the lifetime of a given instance, to be able to grep the kill routine directly at the devm_memremap_pages() call site. Link: http://lkml.kernel.org/r/154275558526.76910.7535251937849268605.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams Fixes: e8d513483300 ("memremap: change devm_memremap_pages interface...") Reviewed-by: "Jérôme Glisse" Reported-by: Logan Gunthorpe Reviewed-by: Logan Gunthorpe Reviewed-by: Christoph Hellwig Cc: Balbir Singh Cc: Michal Hocko Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm, devm_memremap_pages: kill mapping "System RAM" support

2019-01-13T08:51:04Z

commit 06489cfbd915ff36c8e36df27f1c2dc60f97ca56 upstream. Given the fact that devm_memremap_pages() requires a percpu_ref that is torn down by devm_memremap_pages_release() the current support for mapping RAM is broken. Support for remapping "System RAM" has been broken since the beginning and there is no existing user of this this code path, so just kill the support and make it an explicit error. This cleanup also simplifies a follow-on patch to fix the error path when setting a devm release action for devm_memremap_pages_release() fails. Link: http://lkml.kernel.org/r/154275557997.76910.14689813630968180480.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams Reviewed-by: "Jérôme Glisse" Reviewed-by: Christoph Hellwig Reviewed-by: Logan Gunthorpe Cc: Balbir Singh Cc: Michal Hocko Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm, devm_memremap_pages: mark devm_memremap_pages() EXPORT_SYMBOL_GPL

2019-01-13T08:51:04Z

commit 808153e1187fa77ac7d7dad261ff476888dcf398 upstream. devm_memremap_pages() is a facility that can create struct page entries for any arbitrary range and give drivers the ability to subvert core aspects of page management. Specifically the facility is tightly integrated with the kernel's memory hotplug functionality. It injects an altmap argument deep into the architecture specific vmemmap implementation to allow allocating from specific reserved pages, and it has Linux specific assumptions about page structure reference counting relative to get_user_pages() and get_user_pages_fast(). It was an oversight and a mistake that this was not marked EXPORT_SYMBOL_GPL from the outset. Again, devm_memremap_pagex() exposes and relies upon core kernel internal assumptions and will continue to evolve along with 'struct page', memory hotplug, and support for new memory types / topologies. Only an in-kernel GPL-only driver is expected to keep up with this ongoing evolution. This interface, and functionality derived from this interface, is not suitable for kernel-external drivers. Link: http://lkml.kernel.org/r/154275557457.76910.16923571232582744134.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams Reviewed-by: Christoph Hellwig Acked-by: Michal Hocko Cc: "Jérôme Glisse" Cc: Balbir Singh Cc: Logan Gunthorpe Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

Merge tag 'libnvdimm-for-4.19_dax-memory-failure' of gitolite.kernel.org:pub/scm/linux/kernel/git/nvdimm/nvdimm

2018-08-26T01:43:59Z

Pull libnvdimm memory-failure update from Dave Jiang: "As it stands, memory_failure() gets thoroughly confused by dev_pagemap backed mappings. The recovery code has specific enabling for several possible page states and needs new enabling to handle poison in dax mappings. In order to support reliable reverse mapping of user space addresses: 1/ Add new locking in the memory_failure() rmap path to prevent races that would typically be handled by the page lock. 2/ Since dev_pagemap pages are hidden from the page allocator and the "compound page" accounting machinery, add a mechanism to determine the size of the mapping that encompasses a given poisoned pfn. 3/ Given pmem errors can be repaired, change the speculatively accessed poison protection, mce_unmap_kpfn(), to be reversible and otherwise allow ongoing access from the kernel. A side effect of this enabling is that MADV_HWPOISON becomes usable for dax mappings, however the primary motivation is to allow the system to survive userspace consumption of hardware-poison via dax. Specifically the current behavior is: mce: Uncorrected hardware memory error in user-access at af34214200 {1}[Hardware Error]: It has been corrected by h/w and requires no further action mce: [Hardware Error]: Machine check events logged {1}[Hardware Error]: event severity: corrected Memory failure: 0xaf34214: reserved kernel page still referenced by 1 users [..] Memory failure: 0xaf34214: recovery action for reserved kernel page: Failed mce: Memory error not recovered ...and with these changes: Injecting memory failure for pfn 0x20cb00 at process virtual address 0x7f763dd00000 Memory failure: 0x20cb00: Killing dax-pmd:5421 due to hardware memory corruption Memory failure: 0x20cb00: recovery action for dax page: Recovered Given all the cross dependencies I propose taking this through nvdimm.git with acks from Naoya, x86/core, x86/RAS, and of course dax folks" * tag 'libnvdimm-for-4.19_dax-memory-failure' of gitolite.kernel.org:pub/scm/linux/kernel/git/nvdimm/nvdimm: libnvdimm, pmem: Restore page attributes when clearing errors x86/memory_failure: Introduce {set, clear}_mce_nospec() x86/mm/pat: Prepare {reserve, free}_memtype() for "decoy" addresses mm, memory_failure: Teach memory_failure() about dev_pagemap pages filesystem-dax: Introduce dax_lock_mapping_entry() mm, memory_failure: Collect mapping size in collect_procs() mm, madvise_inject_error: Let memory_failure() optionally take a page reference mm, dev_pagemap: Do not clear ->mapping on final put mm, madvise_inject_error: Disable MADV_SOFT_OFFLINE for ZONE_DEVICE pages filesystem-dax: Set page->index device-dax: Set page->index device-dax: Enable page_mapping() device-dax: Convert to vmf_insert_mixed and vm_fault_t

mm: Change return type int to vm_fault_t for fault handlers

2018-08-24T01:48:44Z

Use new return type vm_fault_t for fault handler. For now, this is just documenting that the function returns a VM_FAULT value rather than an errno. Once all instances are converted, vm_fault_t will become a distinct type. Ref-> commit 1c8f422059ae ("mm: change return type to vm_fault_t") The aim is to change the return type of finish_fault() and handle_mm_fault() to vm_fault_t type. As part of that clean up return type of all other recursively called functions have been changed to vm_fault_t type. The places from where handle_mm_fault() is getting invoked will be change to vm_fault_t type but in a separate patch. vmf_error() is the newly introduce inline function in 4.17-rc6. [akpm@linux-foundation.org: don't shadow outer local `ret' in __do_huge_pmd_anonymous_page()] Link: http://lkml.kernel.org/r/20180604171727.GA20279@jordon-HP-15-Notebook-PC Signed-off-by: Souptick Joarder Reviewed-by: Matthew Wilcox Reviewed-by: Andrew Morton Cc: Matthew Wilcox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kernel/memremap, kasan: make ZONE_DEVICE with work with KASAN

2018-08-17T23:20:30Z

KASAN learns about hotadded memory via the memory hotplug notifier. devm_memremap_pages() intentionally skips calling memory hotplug notifiers. So KASAN doesn't know anything about new memory added by devm_memremap_pages(). This causes a crash when KASAN tries to access non-existent shadow memory: BUG: unable to handle kernel paging request at ffffed0078000000 RIP: 0010:check_memory_region+0x82/0x1e0 Call Trace: memcpy+0x1f/0x50 pmem_do_bvec+0x163/0x720 pmem_make_request+0x305/0xac0 generic_make_request+0x54f/0xcf0 submit_bio+0x9c/0x370 submit_bh_wbc+0x4c7/0x700 block_read_full_page+0x5ef/0x870 do_read_cache_page+0x2b8/0xb30 read_dev_sector+0xbd/0x3f0 read_lba.isra.0+0x277/0x670 efi_partition+0x41a/0x18f0 check_partition+0x30d/0x5e9 rescan_partitions+0x18c/0x840 __blkdev_get+0x859/0x1060 blkdev_get+0x23f/0x810 __device_add_disk+0x9c8/0xde0 pmem_attach_disk+0x9a8/0xf50 nvdimm_bus_probe+0xf3/0x3c0 driver_probe_device+0x493/0xbd0 bus_for_each_drv+0x118/0x1b0 __device_attach+0x1cd/0x2b0 bus_probe_device+0x1ac/0x260 device_add+0x90d/0x1380 nd_async_device_register+0xe/0x50 async_run_entry_fn+0xc3/0x5d0 process_one_work+0xa0a/0x1810 worker_thread+0x87/0xe80 kthread+0x2d7/0x390 ret_from_fork+0x3a/0x50 Add kasan_add_zero_shadow()/kasan_remove_zero_shadow() - post mm_init() interface to map/unmap kasan_zero_page at requested virtual addresses. And use it to add/remove the shadow memory for hotplugged/unplugged device memory. Link: http://lkml.kernel.org/r/20180629164932.740-1-aryabinin@virtuozzo.com Fixes: 41e94a851304 ("add devm_memremap_pages") Signed-off-by: Andrey Ryabinin Reported-by: Dave Chinner Reviewed-by: Dan Williams Tested-by: Dan Williams Cc: Dmitry Vyukov Cc: Alexander Potapenko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds