user/sven/linux.git/drivers/base/memory.c, branch v4.4.294

base/memory, hotplug: fix a kernel oops in show_valid_zones()

2017-02-09T07:02:47Z

commit a96dfddbcc04336bbed50dc2b24823e45e09e80c upstream. Reading a sysfs "memoryN/valid_zones" file leads to the following oops when the first page of a range is not backed by struct page. show_valid_zones() assumes that 'start_pfn' is always valid for page_zone(). BUG: unable to handle kernel paging request at ffffea017a000000 IP: show_valid_zones+0x6f/0x160 This issue may happen on x86-64 systems with 64GiB or more memory since their memory block size is bumped up to 2GiB. [1] An example of such systems is desribed below. 0x3240000000 is only aligned by 1GiB and this memory block starts from 0x3200000000, which is not backed by struct page. BIOS-e820: [mem 0x0000003240000000-0x000000603fffffff] usable Since test_pages_in_a_zone() already checks holes, fix this issue by extending this function to return 'valid_start' and 'valid_end' for a given range. show_valid_zones() then proceeds with the valid range. [1] 'Commit bdee237c0343 ("x86: mm: Use 2GB memory block size on large-memory x86-64 systems")' Link: http://lkml.kernel.org/r/20170127222149.30893-3-toshi.kani@hpe.com Signed-off-by: Toshi Kani Cc: Greg Kroah-Hartman Cc: Zhang Zhen Cc: Reza Arbab Cc: David Rientjes Cc: Dan Williams Cc: [4.4+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

drivers/base/memory.c: prohibit offlining of memory blocks with missing sections

2015-12-12T18:15:34Z

Commit bdee237c0343 ("x86: mm: Use 2GB memory block size on large-memory x86-64 systems") and 982792c782ef ("x86, mm: probe memory block size for generic x86 64bit") introduced large block sizes for x86. This made it possible to have multiple sections per memory block where previously, there was a only every one section per block. Since blocks consist of contiguous ranges of section, there can be holes in the blocks where sections are not present. If one attempts to offline such a block, a crash occurs since the code is not designed to deal with this. This patch is a quick fix to gaurd against the crash by not allowing blocks with non-present sections to be offlined. Addresses https://bugzilla.kernel.org/show_bug.cgi?id=107781 Signed-off-by: Seth Jennings Reported-by: Andrew Banman Cc: Daniel J Blueman Cc: Yinghai Lu Cc: Greg KH Cc: Russ Anderson Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm, hotplug: fix concurrent memory hot-add deadlock

2015-04-14T23:49:00Z

There's a deadlock when concurrently hot-adding memory through the probe interface and switching a memory block from offline to online. When hot-adding memory via the probe interface, add_memory() first takes mem_hotplug_begin() and then device_lock() is later taken when registering the newly initialized memory block. This creates a lock dependency of (1) mem_hotplug.lock (2) dev->mutex. When switching a memory block from offline to online, dev->mutex is first grabbed in device_online() when the write(2) transitions an existing memory block from offline to online, and then online_pages() will take mem_hotplug_begin(). This creates a lock inversion between mem_hotplug.lock and dev->mutex. Vitaly reports that this deadlock can happen when kworker handling a probe event races with systemd-udevd switching a memory block's state. This patch requires the state transition to take mem_hotplug_begin() before dev->mutex. Hot-adding memory via the probe interface creates a memory block while holding mem_hotplug_begin(), there is no way to take dev->mutex first in this case. online_pages() and offline_pages() are only called when transitioning memory block state. We now require that mem_hotplug_begin() is taken before calling them -- this requires exporting the mem_hotplug_begin() and mem_hotplug_done() to generic code. In all hot-add and hot-remove cases, mem_hotplug_begin() is done prior to device_online(). This is all that is needed to avoid the deadlock. Signed-off-by: David Rientjes Reported-by: Vitaly Kuznetsov Tested-by: Vitaly Kuznetsov Cc: Greg Kroah-Hartman Cc: "Rafael J. Wysocki" Cc: "K. Y. Srinivasan" Cc: Yasuaki Ishimatsu Cc: Tang Chen Cc: Vlastimil Babka Cc: Zhang Zhen Cc: Vladimir Davydov Cc: Wang Nan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

memory hotplug: use macro to switch between section and pfn

2015-04-14T23:49:00Z

Use macro section_nr_to_pfn() to switch between section and pfn, instead of open-coding it. No semantic changes. Signed-off-by: Sheng Yong Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

drivers: base: memory: Use tabs instead of spaces

2015-03-25T13:36:20Z

This patch changes spaces to tabs. Found using checkpatch.pl Signed-off-by: Ioana Ciornei Signed-off-by: Greg Kroah-Hartman

drivers: base: memory: Fix switch indent

2015-03-25T13:35:08Z

Signed-off-by: Ioana Ciornei Signed-off-by: Greg Kroah-Hartman

memory-hotplug: remove redundant call of page_to_pfn

2014-12-13T20:42:47Z

This is just a small optimization. The start_pfn can be obtained directly by phys_index << PFN_SECTION_SHIFT. So the call of page_to_pfn() is redundant and remove it. Signed-off-by: Zhang Zhen Acked-by: Yasuaki Ishimatsu Acked-by: David Rientjes Cc: Dave Hansen Cc: Wang Nan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

memory-hotplug: add sysfs valid_zones attribute

2014-10-10T02:25:52Z

Currently memory-hotplug has two limits: 1. If the memory block is in ZONE_NORMAL, you can change it to ZONE_MOVABLE, but this memory block must be adjacent to ZONE_MOVABLE. 2. If the memory block is in ZONE_MOVABLE, you can change it to ZONE_NORMAL, but this memory block must be adjacent to ZONE_NORMAL. With this patch, we can easy to know a memory block can be onlined to which zone, and don't need to know the above two limits. Updated the related Documentation. [akpm@linux-foundation.org: use conventional comment layout] [akpm@linux-foundation.org: fix build with CONFIG_MEMORY_HOTREMOVE=n] [akpm@linux-foundation.org: remove unused local zone_prev] Signed-off-by: Zhang Zhen Cc: Dave Hansen Cc: David Rientjes Cc: Toshi Kani Cc: Yasuaki Ishimatsu Cc: Naoya Horiguchi Cc: Wang Nan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/mem-hotplug: replace simple_strtoull() with kstrtoull()

2014-08-07T01:01:18Z

Use the newer and more pleasant kstrtoull() to replace simple_strtoull(), because simple_strtoull() is marked for obsoletion. Signed-off-by: Zhang Zhen Acked-by: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mem-hotplug: introduce MMOP_OFFLINE to replace the hard coding -1

2014-08-07T01:01:16Z

In store_mem_state(), we have: ... 334 else if (!strncmp(buf, "offline", min_t(int, count, 7))) 335 online_type = -1; ... 355 case -1: 356 ret = device_offline(&mem->dev); 357 break; ... Here, "offline" is hard coded as -1. This patch does the following renaming: ONLINE_KEEP -> MMOP_ONLINE_KEEP ONLINE_KERNEL -> MMOP_ONLINE_KERNEL ONLINE_MOVABLE -> MMOP_ONLINE_MOVABLE and introduces MMOP_OFFLINE = -1 to avoid hard coding. Signed-off-by: Tang Chen Cc: Hu Tao Cc: Greg Kroah-Hartman Cc: Lai Jiangshan Cc: Yasuaki Ishimatsu Cc: Gu Zheng Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds