user/sven/linux.git/mm/memory_hotplug.c, branch v3.16.52

mm/memory_hotplug: define find_{smallest|biggest}_section_pfn as unsigned long

2018-01-01T20:51:48Z

commit d09b0137d204bebeaafed672bc5a244e9ac92edb upstream. find_{smallest|biggest}_section_pfn()s find the smallest/biggest section and return the pfn of the section. But the functions are defined as int. So the functions always return 0x00000000 - 0xffffffff. It means if memory address is over 16TB, the functions does not work correctly. To handle 64 bit value, the patch defines find_{smallest|biggest}_section_pfn() as unsigned long. Fixes: 815121d2b5cd ("memory_hotplug: clear zone when removing the memory") Link: http://lkml.kernel.org/r/d9d5593a-d0a4-c4be-ab08-493df59a85c6@gmail.com Signed-off-by: Yasuaki Ishimatsu Acked-by: Michal Hocko Cc: Xishi Qiu Cc: Reza Arbab Cc: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings

mm/memory_hotplug: change pfn_to_section_nr/section_nr_to_pfn macro to inline function

2018-01-01T20:51:48Z

commit 1dd2bfc86818ddbc95f98e312e7704350223fd7d upstream. pfn_to_section_nr() and section_nr_to_pfn() are defined as macro. pfn_to_section_nr() has no issue even if it is defined as macro. But section_nr_to_pfn() has overflow issue if sec is defined as int. section_nr_to_pfn() just shifts sec by PFN_SECTION_SHIFT. If sec is defined as unsigned long, section_nr_to_pfn() returns pfn as 64 bit value. But if sec is defined as int, section_nr_to_pfn() returns pfn as 32 bit value. __remove_section() calculates start_pfn using section_nr_to_pfn() and scn_nr defined as int. So if hot-removed memory address is over 16TB, overflow issue occurs and section_nr_to_pfn() does not calculate correct pfn. To make callers use proper arg, the patch changes the macros to inline functions. Fixes: 815121d2b5cd ("memory_hotplug: clear zone when removing the memory") Link: http://lkml.kernel.org/r/e643a387-e573-6bbf-d418-c60c8ee3d15e@gmail.com Signed-off-by: Yasuaki Ishimatsu Acked-by: Michal Hocko Cc: Xishi Qiu Cc: Reza Arbab Cc: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings

mm/hugetlb: check for reserved hugepages during memory offline

2017-02-23T03:54:10Z

commit 082d5b6b60e9f25e1511557fcfcb21eedd267446 upstream. In dissolve_free_huge_pages(), free hugepages will be dissolved without making sure that there are enough of them left to satisfy hugepage reservations. Fix this by adding a return value to dissolve_free_huge_pages() and checking h->free_huge_pages vs. h->resv_huge_pages. Note that this may lead to the situation where dissolve_free_huge_page() returns an error and all free hugepages that were dissolved before that error are lost, while the memory block still cannot be set offline. Fixes: c8721bbb ("mm: memory-hotplug: enable memory hotplug to handle hugepage") Link: http://lkml.kernel.org/r/20160926172811.94033-3-gerald.schaefer@de.ibm.com Signed-off-by: Gerald Schaefer Acked-by: Michal Hocko Acked-by: Naoya Horiguchi Cc: "Kirill A . Shutemov" Cc: Vlastimil Babka Cc: Mike Kravetz Cc: "Aneesh Kumar K . V" Cc: Martin Schwidefsky Cc: Heiko Carstens Cc: Rui Teng Cc: Dave Hansen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings

mm/memory_hotplug.c: check for missing sections in test_pages_in_a_zone()

2016-01-25T10:43:59Z

commit 5f0f2887f4de9508dcf438deab28f1de8070c271 upstream. test_pages_in_a_zone() does not account for the possibility of missing sections in the given pfn range. pfn_valid_within always returns 1 when CONFIG_HOLES_IN_ZONE is not set, allowing invalid pfns from missing sections to pass the test, leading to a kernel oops. Wrap an additional pfn loop with PAGES_PER_SECTION granularity to check for missing sections before proceeding into the zone-check code. This also prevents a crash from offlining memory devices with missing sections. Despite this, it may be a good idea to keep the related patch '[PATCH 3/3] drivers: memory: prohibit offlining of memory blocks with missing sections' because missing sections in a memory block may lead to other problems not covered by the scope of this fix. Signed-off-by: Andrew Banman Acked-by: Alex Thorlton Cc: Russ Anderson Cc: Alex Thorlton Cc: Yinghai Lu Cc: Greg KH Cc: Seth Jennings Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Luis Henriques

mm/memory_hotplug.c: set zone->wait_table to null after freeing it

2015-06-30T16:15:23Z

commit 85bd839983778fcd0c1c043327b14a046e979b39 upstream. Izumi found the following oops when hot re-adding a node: BUG: unable to handle kernel paging request at ffffc90008963690 IP: __wake_up_bit+0x20/0x70 Oops: 0000 [#1] SMP CPU: 68 PID: 1237 Comm: rs:main Q:Reg Not tainted 4.1.0-rc5 #80 Hardware name: FUJITSU PRIMEQUEST2800E/SB, BIOS PRIMEQUEST 2000 Series BIOS Version 1.87 04/28/2015 task: ffff880838df8000 ti: ffff880017b94000 task.ti: ffff880017b94000 RIP: 0010:[] [] __wake_up_bit+0x20/0x70 RSP: 0018:ffff880017b97be8 EFLAGS: 00010246 RAX: ffffc90008963690 RBX: 00000000003c0000 RCX: 000000000000a4c9 RDX: 0000000000000000 RSI: ffffea101bffd500 RDI: ffffc90008963648 RBP: ffff880017b97c08 R08: 0000000002000020 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8a0797c73800 R13: ffffea101bffd500 R14: 0000000000000001 R15: 00000000003c0000 FS: 00007fcc7ffff700(0000) GS:ffff880874800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffc90008963690 CR3: 0000000836761000 CR4: 00000000001407e0 Call Trace: unlock_page+0x6d/0x70 generic_write_end+0x53/0xb0 xfs_vm_write_end+0x29/0x80 [xfs] generic_perform_write+0x10a/0x1e0 xfs_file_buffered_aio_write+0x14d/0x3e0 [xfs] xfs_file_write_iter+0x79/0x120 [xfs] __vfs_write+0xd4/0x110 vfs_write+0xac/0x1c0 SyS_write+0x58/0xd0 system_call_fastpath+0x12/0x76 Code: 5d c3 66 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 55 48 89 e5 48 83 ec 20 65 48 8b 04 25 28 00 00 00 48 89 45 f8 31 c0 48 8d 47 48 <48> 39 47 48 48 c7 45 e8 00 00 00 00 48 c7 45 f0 00 00 00 00 48 RIP [] __wake_up_bit+0x20/0x70 RSP CR2: ffffc90008963690 Reproduce method (re-add a node):: Hot-add nodeA --> remove nodeA --> hot-add nodeA (panic) This seems an use-after-free problem, and the root cause is zone->wait_table was not set to *NULL* after free it in try_offline_node. When hot re-add a node, we will reuse the pgdat of it, so does the zone struct, and when add pages to the target zone, it will init the zone first (including the wait_table) if the zone is not initialized. The judgement of zone initialized is based on zone->wait_table: static inline bool zone_is_initialized(struct zone *zone) { return !!zone->wait_table; } so if we do not set the zone->wait_table to *NULL* after free it, the memory hotplug routine will skip the init of new zone when hot re-add the node, and the wait_table still points to the freed memory, then we will access the invalid address when trying to wake up the waiting people after the i/o operation with the page is done, such as mentioned above. Signed-off-by: Gu Zheng Reported-by: Taku Izumi Reviewed by: Yasuaki Ishimatsu Cc: KAMEZAWA Hiroyuki Cc: Tang Chen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Luis Henriques

mm/memory hotplug: postpone the reset of obsolete pgdat

2015-04-10T09:04:06Z

commit b0dc3a342af36f95a68fe229b8f0f73552c5ca08 upstream. Qiu Xishi reported the following BUG when testing hot-add/hot-remove node under stress condition: BUG: unable to handle kernel paging request at 0000000000025f60 IP: next_online_pgdat+0x1/0x50 PGD 0 Oops: 0000 [#1] SMP ACPI: Device does not support D3cold Modules linked in: fuse nls_iso8859_1 nls_cp437 vfat fat loop dm_mod coretemp mperf crc32c_intel ghash_clmulni_intel aesni_intel ablk_helper cryptd lrw gf128mul glue_helper aes_x86_64 pcspkr microcode igb dca i2c_algo_bit ipv6 megaraid_sas iTCO_wdt i2c_i801 i2c_core iTCO_vendor_support tg3 sg hwmon ptp lpc_ich pps_core mfd_core acpi_pad rtc_cmos button ext3 jbd mbcache sd_mod crc_t10dif scsi_dh_alua scsi_dh_rdac scsi_dh_hp_sw scsi_dh_emc scsi_dh ahci libahci libata scsi_mod [last unloaded: rasf] CPU: 23 PID: 238 Comm: kworker/23:1 Tainted: G O 3.10.15-5885-euler0302 #1 Hardware name: HUAWEI TECHNOLOGIES CO.,LTD. Huawei N1/Huawei N1, BIOS V100R001 03/02/2015 Workqueue: events vmstat_update task: ffffa800d32c0000 ti: ffffa800d32ae000 task.ti: ffffa800d32ae000 RIP: 0010: next_online_pgdat+0x1/0x50 RSP: 0018:ffffa800d32afce8 EFLAGS: 00010286 RAX: 0000000000001440 RBX: ffffffff81da53b8 RCX: 0000000000000082 RDX: 0000000000000000 RSI: 0000000000000082 RDI: 0000000000000000 RBP: ffffa800d32afd28 R08: ffffffff81c93bfc R09: ffffffff81cbdc96 R10: 00000000000040ec R11: 00000000000000a0 R12: ffffa800fffb3440 R13: ffffa800d32afd38 R14: 0000000000000017 R15: ffffa800e6616800 FS: 0000000000000000(0000) GS:ffffa800e6600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000025f60 CR3: 0000000001a0b000 CR4: 00000000001407e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: refresh_cpu_vm_stats+0xd0/0x140 vmstat_update+0x11/0x50 process_one_work+0x194/0x3d0 worker_thread+0x12b/0x410 kthread+0xc6/0xd0 ret_from_fork+0x7c/0xb0 The cause is the "memset(pgdat, 0, sizeof(*pgdat))" at the end of try_offline_node, which will reset all the content of pgdat to 0, as the pgdat is accessed lock-free, so that the users still using the pgdat will panic, such as the vmstat_update routine. process A: offline node XX: vmstat_updat() refresh_cpu_vm_stats() for_each_populated_zone() find online node XX cond_resched() offline cpu and memory, then try_offline_node() node_set_offline(nid), and memset(pgdat, 0, sizeof(*pgdat)) zone = next_zone(zone) pg_data_t *pgdat = zone->zone_pgdat; // here pgdat is NULL now next_online_pgdat(pgdat) next_online_node(pgdat->node_id); // NULL pointer access So the solution here is postponing the reset of obsolete pgdat from try_offline_node() to hotadd_new_pgdat(), and just resetting pgdat->nr_zones and pgdat->classzone_idx to be 0 rather than the memset 0 to avoid breaking pointer information in pgdat. Signed-off-by: Gu Zheng Reported-by: Xishi Qiu Suggested-by: KAMEZAWA Hiroyuki Cc: David Rientjes Cc: Yasuaki Ishimatsu Cc: Taku Izumi Cc: Tang Chen Cc: Xie XiuQi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Luis Henriques

mem-hotplug: reset node present pages when hot-adding a new pgdat

2014-11-27T11:21:51Z

commit 0bd854200873894a76f32603ff2c4c988ad6b5b5 upstream. When memory is hot-added, all the memory is in offline state. So clear all zones' present_pages because they will be updated in online_pages() and offline_pages(). Otherwise, /proc/zoneinfo will corrupt: When the memory of node2 is offline: # cat /proc/zoneinfo ...... Node 2, zone Movable ...... spanned 8388608 present 8388608 managed 0 When we online memory on node2: # cat /proc/zoneinfo ...... Node 2, zone Movable ...... spanned 8388608 present 16777216 managed 8388608 Signed-off-by: Tang Chen Reviewed-by: Yasuaki Ishimatsu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Luis Henriques

mem-hotplug: reset node managed pages when hot-adding a new pgdat

2014-11-27T11:21:50Z

commit f784a3f19613901ca4539a5b0eed3bdc700e6ee7 upstream. In free_area_init_core(), zone->managed_pages is set to an approximate value for lowmem, and will be adjusted when the bootmem allocator frees pages into the buddy system. But free_area_init_core() is also called by hotadd_new_pgdat() when hot-adding memory. As a result, zone->managed_pages of the newly added node's pgdat is set to an approximate value in the very beginning. Even if the memory on that node has node been onlined, /sys/device/system/node/nodeXXX/meminfo has wrong value: hot-add node2 (memory not onlined) cat /sys/device/system/node/node2/meminfo Node 2 MemTotal: 33554432 kB Node 2 MemFree: 0 kB Node 2 MemUsed: 33554432 kB Node 2 Active: 0 kB This patch fixes this problem by reset node managed pages to 0 after hot-adding a new node. 1. Move reset_managed_pages_done from reset_node_managed_pages() to reset_all_zones_managed_pages() 2. Make reset_node_managed_pages() non-static 3. Call reset_node_managed_pages() in hotadd_new_pgdat() after pgdat is initialized Signed-off-by: Tang Chen Signed-off-by: Yasuaki Ishimatsu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Luis Henriques

mm, migration: add destination page freeing callback

2014-06-04T23:54:06Z

Memory migration uses a callback defined by the caller to determine how to allocate destination pages. When migration fails for a source page, however, it frees the destination page back to the system. This patch adds a memory migration callback defined by the caller to determine how to free destination pages. If a caller, such as memory compaction, builds its own freelist for migration targets, this can reuse already freed memory instead of scanning additional memory. If the caller provides a function to handle freeing of destination pages, it is called when page migration fails. If the caller passes NULL then freeing back to the system will be handled as usual. This patch introduces no functional change. Signed-off-by: David Rientjes Reviewed-by: Naoya Horiguchi Acked-by: Mel Gorman Acked-by: Vlastimil Babka Cc: Greg Thelen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/memory_hotplug.c: use PFN_DOWN()

2014-06-04T23:54:02Z

Replace ((x) >> PAGE_SHIFT) with the pfn macro. Signed-off-by: Fabian Frederick Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds