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Patch series "mm: page_ext: Introduce new iteration API", v3.
Introduction
============
[ Thanks to David Hildenbrand for identifying the root cause of this
issue and proving guidance on how to fix it. The new API idea, bugs
and misconceptions are all mine though ]
Currently, trying to reserve 1G pages with page_owner=on and sparsemem
causes a crash. The reproducer is very simple:
1. Build the kernel with CONFIG_SPARSEMEM=y and the table extensions
2. Pass 'default_hugepagesz=1 page_owner=on' in the kernel command-line
3. Reserve one 1G page at run-time, this should crash (see patch 1 for
backtrace)
[ A crash with page_table_check is also possible, but harder to trigger ]
Apparently, starting with commit cf54f310d0d3 ("mm/hugetlb: use __GFP_COMP
for gigantic folios") we now pass the full allocation order to page
extension clients and the page extension implementation assumes that all
PFNs of an allocation range will be stored in the same memory section (which
is not true for 1G pages).
To fix this, this series introduces a new iteration API for page extension
objects. The API checks if the next page extension object can be retrieved
from the current section or if it needs to look up for it in another
section.
Please, find all details in patch 1.
I tested this series on arm64 and x86 by reserving 1G pages at run-time
and doing kernel builds (always with page_owner=on and page_table_check=on).
This patch (of 3):
The page extension implementation assumes that all page extensions of a
given page order are stored in the same memory section. The function
page_ext_next() relies on this assumption by adding an offset to the
current object to return the next adjacent page extension.
This behavior works as expected for flatmem but fails for sparsemem when
using 1G pages. The commit cf54f310d0d3 ("mm/hugetlb: use __GFP_COMP for
gigantic folios") exposes this issue, making it possible for a crash when
using page_owner or page_table_check page extensions.
The problem is that for 1G pages, the page extensions may span memory
section boundaries and be stored in different memory sections. This issue
was not visible before commit cf54f310d0d3 ("mm/hugetlb: use __GFP_COMP
for gigantic folios") because alloc_contig_pages() never passed more than
MAX_PAGE_ORDER to post_alloc_hook(). However, the series introducing
mentioned commit changed this behavior allowing the full 1G page order to
be passed.
Reproducer:
1. Build the kernel with CONFIG_SPARSEMEM=y and table extensions
support
2. Pass 'default_hugepagesz=1 page_owner=on' in the kernel command-line
3. Reserve one 1G page at run-time, this should crash (backtrace below)
To address this issue, this commit introduces a new API for iterating
through page extensions. The main iteration macro is for_each_page_ext()
and it must be called with the RCU read lock taken. Here's an usage
example:
"""
struct page_ext_iter iter;
struct page_ext *page_ext;
...
rcu_read_lock();
for_each_page_ext(page, 1 << order, page_ext, iter) {
struct my_page_ext *obj = get_my_page_ext_obj(page_ext);
...
}
rcu_read_unlock();
"""
The loop construct uses page_ext_iter_next() which checks to see if we
have crossed sections in the iteration. In this case,
page_ext_iter_next() retrieves the next page_ext object from another
section.
Thanks to David Hildenbrand for helping identify the root cause and
providing suggestions on how to fix and optmize the solution (final
implementation and bugs are all mine through).
Lastly, here's the backtrace, without kasan you can get random crashes:
[ 76.052526] BUG: KASAN: slab-out-of-bounds in __update_page_owner_handle+0x238/0x298
[ 76.060283] Write of size 4 at addr ffff07ff96240038 by task tee/3598
[ 76.066714]
[ 76.068203] CPU: 88 UID: 0 PID: 3598 Comm: tee Kdump: loaded Not tainted 6.13.0-rep1 #3
[ 76.076202] Hardware name: WIWYNN Mt.Jade Server System B81.030Z1.0007/Mt.Jade Motherboard, BIOS 2.10.20220810 (SCP: 2.10.20220810) 2022/08/10
[ 76.088972] Call trace:
[ 76.091411] show_stack+0x20/0x38 (C)
[ 76.095073] dump_stack_lvl+0x80/0xf8
[ 76.098733] print_address_description.constprop.0+0x88/0x398
[ 76.104476] print_report+0xa8/0x278
[ 76.108041] kasan_report+0xa8/0xf8
[ 76.111520] __asan_report_store4_noabort+0x20/0x30
[ 76.116391] __update_page_owner_handle+0x238/0x298
[ 76.121259] __set_page_owner+0xdc/0x140
[ 76.125173] post_alloc_hook+0x190/0x1d8
[ 76.129090] alloc_contig_range_noprof+0x54c/0x890
[ 76.133874] alloc_contig_pages_noprof+0x35c/0x4a8
[ 76.138656] alloc_gigantic_folio.isra.0+0x2c0/0x368
[ 76.143616] only_alloc_fresh_hugetlb_folio.isra.0+0x24/0x150
[ 76.149353] alloc_pool_huge_folio+0x11c/0x1f8
[ 76.153787] set_max_huge_pages+0x364/0xca8
[ 76.157961] __nr_hugepages_store_common+0xb0/0x1a0
[ 76.162829] nr_hugepages_store+0x108/0x118
[ 76.167003] kobj_attr_store+0x3c/0x70
[ 76.170745] sysfs_kf_write+0xfc/0x188
[ 76.174492] kernfs_fop_write_iter+0x274/0x3e0
[ 76.178927] vfs_write+0x64c/0x8e0
[ 76.182323] ksys_write+0xf8/0x1f0
[ 76.185716] __arm64_sys_write+0x74/0xb0
[ 76.189630] invoke_syscall.constprop.0+0xd8/0x1e0
[ 76.194412] do_el0_svc+0x164/0x1e0
[ 76.197891] el0_svc+0x40/0xe0
[ 76.200939] el0t_64_sync_handler+0x144/0x168
[ 76.205287] el0t_64_sync+0x1ac/0x1b0
Link: https://lkml.kernel.org/r/cover.1741301089.git.luizcap@redhat.com
Link: https://lkml.kernel.org/r/a45893880b7e1601082d39d2c5c8b50bcc096305.1741301089.git.luizcap@redhat.com
Fixes: cf54f310d0d3 ("mm/hugetlb: use __GFP_COMP for gigantic folios")
Signed-off-by: Luiz Capitulino <luizcap@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Luiz Capitulino <luizcap@redhat.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Fix invalid access to pgdat during hot-remove operation:
ndctl users reported a GPF when trying to destroy a namespace:
$ ndctl destroy-namespace all -r all -f
Segmentation fault
dmesg:
Oops: general protection fault, probably for
non-canonical address 0xdffffc0000005650: 0000 [#1] PREEMPT SMP KASAN
PTI
KASAN: probably user-memory-access in range
[0x000000000002b280-0x000000000002b287]
CPU: 26 UID: 0 PID: 1868 Comm: ndctl Not tainted 6.11.0-rc1 #1
Hardware name: Dell Inc. PowerEdge R640/08HT8T, BIOS
2.20.1 09/13/2023
RIP: 0010:mod_node_page_state+0x2a/0x110
cxl-test users report a GPF when trying to unload the test module:
$ modrpobe -r cxl-test
dmesg
BUG: unable to handle page fault for address: 0000000000004200
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 0 UID: 0 PID: 1076 Comm: modprobe Tainted: G O N 6.11.0-rc1 #197
Tainted: [O]=OOT_MODULE, [N]=TEST
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/15
RIP: 0010:mod_node_page_state+0x6/0x90
Currently, when memory is hot-plugged or hot-removed the accounting is
done based on the assumption that memmap is allocated from the same node
as the hot-plugged/hot-removed memory, which is not always the case.
In addition, there are challenges with keeping the node id of the memory
that is being remove to the time when memmap accounting is actually
performed: since this is done after remove_pfn_range_from_zone(), and
also after remove_memory_block_devices(). Meaning that we cannot use
pgdat nor walking though memblocks to get the nid.
Given all of that, account the memmap overhead system wide instead.
For this we are going to be using global atomic counters, but given that
memmap size is rarely modified, and normally is only modified either
during early boot when there is only one CPU, or under a hotplug global
mutex lock, therefore there is no need for per-cpu optimizations.
Also, while we are here rename nr_memmap to nr_memmap_pages, and
nr_memmap_boot to nr_memmap_boot_pages to be self explanatory that the
units are in page count.
[pasha.tatashin@soleen.com: address a few nits from David Hildenbrand]
Link: https://lkml.kernel.org/r/20240809191020.1142142-4-pasha.tatashin@soleen.com
Link: https://lkml.kernel.org/r/20240809191020.1142142-4-pasha.tatashin@soleen.com
Link: https://lkml.kernel.org/r/20240808213437.682006-4-pasha.tatashin@soleen.com
Fixes: 15995a352474 ("mm: report per-page metadata information")
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Closes: https://lore.kernel.org/linux-cxl/CAHj4cs9Ax1=CoJkgBGP_+sNu6-6=6v=_L-ZBZY0bVLD3wUWZQg@mail.gmail.com
Reported-by: Alison Schofield <alison.schofield@intel.com>
Closes: https://lore.kernel.org/linux-mm/Zq0tPd2h6alFz8XF@aschofie-mobl2/#t
Tested-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Alison Schofield <alison.schofield@intel.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Tested-by: Yi Zhang <yi.zhang@redhat.com>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Fan Ni <fan.ni@samsung.com>
Cc: Joel Granados <j.granados@samsung.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Li Zhijian <lizhijian@fujitsu.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Sourav Panda <souravpanda@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Today, we do not have any observability of per-page metadata and how much
it takes away from the machine capacity. Thus, we want to describe the
amount of memory that is going towards per-page metadata, which can vary
depending on build configuration, machine architecture, and system use.
This patch adds 2 fields to /proc/vmstat that can used as shown below:
Accounting per-page metadata allocated by boot-allocator:
/proc/vmstat:nr_memmap_boot * PAGE_SIZE
Accounting per-page metadata allocated by buddy-allocator:
/proc/vmstat:nr_memmap * PAGE_SIZE
Accounting total Perpage metadata allocated on the machine:
(/proc/vmstat:nr_memmap_boot +
/proc/vmstat:nr_memmap) * PAGE_SIZE
Utility for userspace:
Observability: Describe the amount of memory overhead that is going to
per-page metadata on the system at any given time since this overhead is
not currently observable.
Debugging: Tracking the changes or absolute value in struct pages can help
detect anomalies as they can be correlated with other metrics in the
machine (e.g., memtotal, number of huge pages, etc).
page_ext overheads: Some kernel features such as page_owner
page_table_check that use page_ext can be optionally enabled via kernel
parameters. Having the total per-page metadata information helps users
precisely measure impact. Furthermore, page-metadata metrics will reflect
the amount of struct pages reliquished (or overhead reduced) when
hugetlbfs pages are reserved which will vary depending on whether hugetlb
vmemmap optimization is enabled or not.
For background and results see:
lore.kernel.org/all/20240220214558.3377482-1-souravpanda@google.com
Link: https://lkml.kernel.org/r/20240605222751.1406125-1-souravpanda@google.com
Signed-off-by: Sourav Panda <souravpanda@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Chen Linxuan <chenlinxuan@uniontech.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ivan Babrou <ivan@cloudflare.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tomas Mudrunka <tomas.mudrunka@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Xu <weixugc@google.com>
Cc: Yang Yang <yang.yang29@zte.com.cn>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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In order to constify other functions, we need page_ext_get() to be const.
This is no problem as lookup_page_ext() already takes a const argument.
Link: https://lkml.kernel.org/r/20240326171045.410737-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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For all page allocations to be tagged, page_ext has to be initialized
before the first page allocation. Early tasks allocate their stacks using
page allocator before alloc_node_page_ext() initializes page_ext area,
unless early_page_ext is enabled. Therefore these allocations will
generate a warning when CONFIG_MEM_ALLOC_PROFILING_DEBUG is enabled.
Enable early_page_ext whenever CONFIG_MEM_ALLOC_PROFILING_DEBUG=y to
ensure page_ext initialization prior to any page allocation. This will
have all the negative effects associated with early_page_ext, such as
possible longer boot time, therefore we enable it only when debugging with
CONFIG_MEM_ALLOC_PROFILING_DEBUG enabled and not universally for
CONFIG_MEM_ALLOC_PROFILING.
Link: https://lkml.kernel.org/r/20240321163705.3067592-22-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Kees Cook <keescook@chromium.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alex Gaynor <alex.gaynor@gmail.com>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Andreas Hindborg <a.hindborg@samsung.com>
Cc: Benno Lossin <benno.lossin@proton.me>
Cc: "Björn Roy Baron" <bjorn3_gh@protonmail.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Gary Guo <gary@garyguo.net>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Wedson Almeida Filho <wedsonaf@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Introduce helper functions to easily instrument page allocators by storing
a pointer to the allocation tag associated with the code that allocated
the page in a page_ext field.
Link: https://lkml.kernel.org/r/20240321163705.3067592-15-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Co-developed-by: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Kees Cook <keescook@chromium.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alex Gaynor <alex.gaynor@gmail.com>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Andreas Hindborg <a.hindborg@samsung.com>
Cc: Benno Lossin <benno.lossin@proton.me>
Cc: "Björn Roy Baron" <bjorn3_gh@protonmail.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Gary Guo <gary@garyguo.net>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Wedson Almeida Filho <wedsonaf@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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1. move page_ext_get and page_ext_put down to remove forward
declaration of lookup_page_ext.
2. move page_ext_init_flatmem_late down to existing non SPARS block to
remove a new non SPARS block and to keep code for non SPARS tight.
Link: https://lkml.kernel.org/r/20230714114749.1743032-4-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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If init_section_page_ext failed, we only need rollback for mem_section
before failed mem_section. Make rollback end point to failed mem_section
to remove unnecessary rollback.
As pfn += PAGES_PER_SECTION will be executed even if init_section_page_ext
failed. So pfn points to mem_section after failed mem_section. Subtract
one mem_section from pfn to get failed mem_section.
Link: https://lkml.kernel.org/r/20230714114749.1743032-3-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "minor cleanups for page_ext".
This series contains some random minor cleanups for page_ext. More
details can be found in respective patches.
This patch (of 3):
offline_page_ext always returns 0 and no caller checks the return value.
Just remove unused return value of offline_page_ext.
Link: https://lkml.kernel.org/r/20230714114749.1743032-1-shikemeng@huaweicloud.com
Link: https://lkml.kernel.org/r/20230714114749.1743032-2-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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page_ext must be initialized after all struct pages are initialized.
Therefore, page_ext is initialized after page_alloc_init_late(), and can
optionally be initialized earlier via early_page_ext kernel parameter
which as a side effect also disables deferred struct pages.
Allow to automatically init page_ext early when there are no deferred
struct pages in order to be able to use page_ext during kernel boot and
track for example page allocations early.
[pasha.tatashin@soleen.com: fix build with CONFIG_PAGE_EXTENSION=n]
Link: https://lkml.kernel.org/r/20230118155251.2522985-1-pasha.tatashin@soleen.com
Link: https://lkml.kernel.org/r/20230117204617.1553748-1-pasha.tatashin@soleen.com
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Charan Teja Kalla <quic_charante@quicinc.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Li Zhe <lizhe.67@bytedance.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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There is 8 byte page_ext->flags field allocated per page whenever
CONFIG_PAGE_EXTENSION is enabled. However, not every user of page_ext
uses flags. Therefore, check whether flags is needed at least by one user
and if so allocate space for it.
For example when page_table_check is enabled, on a machine with 128G
of memory before the fix:
[ 2.244288] allocated 536870912 bytes of page_ext
after the fix:
[ 2.160154] allocated 268435456 bytes of page_ext
Also, add a kernel-doc comment before page_ext_operations that describes
the fields, and remove check if need() is set, as that is now a required
field.
[pasha.tatashin@soleen.com: address comments from Mike Rapoport]
Link: https://lkml.kernel.org/r/20230117202103.1412449-1-pasha.tatashin@soleen.com
Link: https://lkml.kernel.org/r/20230113154253.92480-1-pasha.tatashin@soleen.com
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Charan Teja Kalla <quic_charante@quicinc.com>
Cc: Li Zhe <lizhe.67@bytedance.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Fix the below compiler warnings reported with 'make W=1 mm/'.
mm/page_ext.c:178: warning: Function parameter or member 'page_ext' not
described in 'page_ext_put'.
[quic_pkondeti@quicinc.com: better patch title]
Link: https://lkml.kernel.org/r/1667884582-2465-1-git-send-email-quic_charante@quicinc.com
Fixes: b1d5488a252dc9 ("mm: fix use-after free of page_ext after race with memory-offline")
Signed-off-by: Charan Teja Kalla <quic_charante@quicinc.com>
Reported-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Pavan Kondeti <quic_pkondeti@quicinc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The priority of hotplug memory callback is defined in a different file.
And there are some callers using numbers directly. Collect them together
into include/linux/memory.h for easy reading. This allows us to sort
their priorities more intuitively without additional comments.
Link: https://lkml.kernel.org/r/20220923033347.3935160-9-liushixin2@huawei.com
Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Waiman Long <longman@redhat.com>
Cc: zefan li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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In commit 2f1ee0913ce5 ("Revert "mm: use early_pfn_to_nid in
page_ext_init""), we call page_ext_init() after page_alloc_init_late() to
avoid some panic problem. It seems that we cannot track early page
allocations in current kernel even if page structure has been initialized
early.
This patch introduces a new boot parameter 'early_page_ext' to resolve
this problem. If we pass it to the kernel, page_ext_init() will be moved
up and the feature 'deferred initialization of struct pages' will be
disabled to initialize the page allocator early and prevent the panic
problem above. It can help us to catch early page allocations. This is
useful especially when we find that the free memory value is not the same
right after different kernel booting.
[akpm@linux-foundation.org: fix section issue by removing __meminitdata]
Link: https://lkml.kernel.org/r/20220825102714.669-1-lizhe.67@bytedance.com
Signed-off-by: Li Zhe <lizhe.67@bytedance.com>
Suggested-by: Michal Hocko <mhocko@suse.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The below is one path where race between page_ext and offline of the
respective memory blocks will cause use-after-free on the access of
page_ext structure.
process1 process2
--------- ---------
a)doing /proc/page_owner doing memory offline
through offline_pages.
b) PageBuddy check is failed
thus proceed to get the
page_owner information
through page_ext access.
page_ext = lookup_page_ext(page);
migrate_pages();
.................
Since all pages are successfully
migrated as part of the offline
operation,send MEM_OFFLINE notification
where for page_ext it calls:
offline_page_ext()-->
__free_page_ext()-->
free_page_ext()-->
vfree(ms->page_ext)
mem_section->page_ext = NULL
c) Check for the PAGE_EXT
flags in the page_ext->flags
access results into the
use-after-free (leading to
the translation faults).
As mentioned above, there is really no synchronization between page_ext
access and its freeing in the memory_offline.
The memory offline steps(roughly) on a memory block is as below:
1) Isolate all the pages
2) while(1)
try free the pages to buddy.(->free_list[MIGRATE_ISOLATE])
3) delete the pages from this buddy list.
4) Then free page_ext.(Note: The struct page is still alive as it is
freed only during hot remove of the memory which frees the memmap,
which steps the user might not perform).
This design leads to the state where struct page is alive but the struct
page_ext is freed, where the later is ideally part of the former which
just representing the page_flags (check [3] for why this design is
chosen).
The abovementioned race is just one example __but the problem persists in
the other paths too involving page_ext->flags access(eg:
page_is_idle())__.
Fix all the paths where offline races with page_ext access by maintaining
synchronization with rcu lock and is achieved in 3 steps:
1) Invalidate all the page_ext's of the sections of a memory block by
storing a flag in the LSB of mem_section->page_ext.
2) Wait until all the existing readers to finish working with the
->page_ext's with synchronize_rcu(). Any parallel process that starts
after this call will not get page_ext, through lookup_page_ext(), for
the block parallel offline operation is being performed.
3) Now safely free all sections ->page_ext's of the block on which
offline operation is being performed.
Note: If synchronize_rcu() takes time then optimizations can be done in
this path through call_rcu()[2].
Thanks to David Hildenbrand for his views/suggestions on the initial
discussion[1] and Pavan kondeti for various inputs on this patch.
[1] https://lore.kernel.org/linux-mm/59edde13-4167-8550-86f0-11fc67882107@quicinc.com/
[2] https://lore.kernel.org/all/a26ce299-aed1-b8ad-711e-a49e82bdd180@quicinc.com/T/#u
[3] https://lore.kernel.org/all/6fa6b7aa-731e-891c-3efb-a03d6a700efa@redhat.com/
[quic_charante@quicinc.com: rename label `loop' to `ext_put_continue' per David]
Link: https://lkml.kernel.org/r/1661496993-11473-1-git-send-email-quic_charante@quicinc.com
Link: https://lkml.kernel.org/r/1660830600-9068-1-git-send-email-quic_charante@quicinc.com
Signed-off-by: Charan Teja Kalla <quic_charante@quicinc.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Suggested-by: Michal Hocko <mhocko@suse.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Fernand Sieber <sieberf@amazon.com>
Cc: Minchan Kim <minchan@google.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Pavan Kondeti <quic_pkondeti@quicinc.com>
Cc: SeongJae Park <sjpark@amazon.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Remove unused variable 'nid' in offline_page_ext(). This is not used
since the page_ext code inception.
Link: https://lkml.kernel.org/r/1659330397-11817-1-git-send-email-quic_charante@quicinc.com
Signed-off-by: Charan Teja Kalla <quic_charante@quicinc.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Pavan Kondeti <quic_pkondeti@quicinc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Use more generic functions to deal with issues related to online nodes.
The changes will make the code simplified.
Link: https://lkml.kernel.org/r/20220429030218.644635-1-liupeng256@huawei.com
Signed-off-by: Peng Liu <liupeng256@huawei.com>
Suggested-by: Davidlohr Bueso <dave@stgolabs.net>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
"page_idle_ops" as a global var, but its scope of use within this
document. So it should be static.
"page_ext_ops" is a var used in the kernel initial phase. And other
functions are aslo used in the kernel initial phase. So they should be
__init or __initdata to reclaim memory.
Link: https://lkml.kernel.org/r/20211217095023.67293-1-liuting.0x7c00@bytedance.com
Signed-off-by: Ting Liu <liuting.0x7c00@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Check user page table entries at the time they are added and removed.
Allows to synchronously catch memory corruption issues related to double
mapping.
When a pte for an anonymous page is added into page table, we verify
that this pte does not already point to a file backed page, and vice
versa if this is a file backed page that is being added we verify that
this page does not have an anonymous mapping
We also enforce that read-only sharing for anonymous pages is allowed
(i.e. cow after fork). All other sharing must be for file pages.
Page table check allows to protect and debug cases where "struct page"
metadata became corrupted for some reason. For example, when refcnt or
mapcount become invalid.
Link: https://lkml.kernel.org/r/20211221154650.1047963-4-pasha.tatashin@soleen.com
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Greg Thelen <gthelen@google.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wei Xu <weixugc@google.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
I have noticed that the previous macro is #ifndef CONFIG_SPARSEMEM. I
think the comment of #else should be CONFIG_SPARSEMEM.
Link: https://lkml.kernel.org/r/20211008140312.6492-1-zhangyinan2019@email.szu.edu.cn
Signed-off-by: Yinan Zhang <zhangyinan2019@email.szu.edu.cn>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Once upon a time, the node demotion updates were driven solely by memory
hotplug events. But now, there are handlers for both CPU and memory
hotplug.
However, the #ifdef around the code checks only memory hotplug. A
system that has HOTPLUG_CPU=y but MEMORY_HOTPLUG=n would miss CPU
hotplug events.
Update the #ifdef around the common code. Add memory and CPU-specific
#ifdefs for their handlers. These memory/CPU #ifdefs avoid unused
function warnings when their Kconfig option is off.
[arnd@arndb.de: rework hotplug_memory_notifier() stub]
Link: https://lkml.kernel.org/r/20211013144029.2154629-1-arnd@kernel.org
Link: https://lkml.kernel.org/r/20210924161255.E5FE8F7E@davehans-spike.ostc.intel.com
Fixes: 884a6e5d1f93 ("mm/migrate: update node demotion order on hotplug events")
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
PG_idle and PG_young allow the two PTE Accessed bit users, Idle Page
Tracking and the reclaim logic concurrently work while not interfering
with each other. That is, when they need to clear the Accessed bit, they
set PG_young to represent the previous state of the bit, respectively.
And when they need to read the bit, if the bit is cleared, they further
read the PG_young to know whether the other has cleared the bit meanwhile
or not.
For yet another user of the PTE Accessed bit, we could add another page
flag, or extend the mechanism to use the flags. For the DAMON usecase,
however, we don't need to do that just yet. IDLE_PAGE_TRACKING and DAMON
are mutually exclusive, so there's only ever going to be one user of the
current set of flags.
In this commit, we split out the CONFIG options to allow for the use of
PG_young and PG_idle outside of idle page tracking.
In the next commit, DAMON's reference implementation of the virtual memory
address space monitoring primitives will use it.
[sjpark@amazon.de: set PAGE_EXTENSION for non-64BIT]
Link: https://lkml.kernel.org/r/20210806095153.6444-1-sj38.park@gmail.com
[akpm@linux-foundation.org: tweak Kconfig text]
[sjpark@amazon.de: hide PAGE_IDLE_FLAG from users]
Link: https://lkml.kernel.org/r/20210813081238.34705-1-sj38.park@gmail.com
Link: https://lkml.kernel.org/r/20210716081449.22187-5-sj38.park@gmail.com
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Fernand Sieber <sieberf@amazon.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Fan Du <fan.du@intel.com>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Maximilian Heyne <mheyne@amazon.de>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
After removal of the DISCONTIGMEM memory model the FLAT_NODE_MEM_MAP
configuration option is equivalent to FLATMEM.
Drop CONFIG_FLAT_NODE_MEM_MAP and use CONFIG_FLATMEM instead.
Link: https://lkml.kernel.org/r/20210608091316.3622-10-rppt@kernel.org
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Fix some spelling mistakes in comments:
udpate ==> update
succesful ==> successful
exmaple ==> example
unneccessary ==> unnecessary
stoping ==> stopping
uknown ==> unknown
Link: https://lkml.kernel.org/r/20201127011747.86005-1-shihaitao1@huawei.com
Signed-off-by: Haitao Shi <shihaitao1@huawei.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Souptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Page owner of pages used by page owner itself used is missing on arm32
targets. The reason is dummy_handle and failure_handle is not initialized
correctly. Buddy allocator is used to initialize these two handles.
However, buddy allocator is not ready when page owner calls it. This
change fixed that by initializing page owner after buddy initialization.
The working flow before and after this change are:
original logic:
1. allocated memory for page_ext(using memblock).
2. invoke the init callback of page_ext_ops like page_owner(using buddy
allocator).
3. initialize buddy.
after this change:
1. allocated memory for page_ext(using memblock).
2. initialize buddy.
3. invoke the init callback of page_ext_ops like page_owner(using buddy
allocator).
with the change, failure/dummy_handle can get its correct value and page
owner output for example has the one for page owner itself:
Page allocated via order 2, mask 0x6202c0(GFP_USER|__GFP_NOWARN), pid 1006, ts 67278156558 ns
PFN 543776 type Unmovable Block 531 type Unmovable Flags 0x0()
init_page_owner+0x28/0x2f8
invoke_init_callbacks_flatmem+0x24/0x34
start_kernel+0x33c/0x5d8
Link: https://lkml.kernel.org/r/1603104925-5888-1-git-send-email-zhenhuah@codeaurora.org
Signed-off-by: Zhenhua Huang <zhenhuah@codeaurora.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Since commit c5e79ef561b0 ("mm/memory_hotplug.c: don't allow to
online/offline memory blocks with holes") we disallow to offline any
memory with holes. As all boot memory is online and hotplugged memory
cannot contain holes, we never online memory with holes.
This present check can be dropped.
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Link: http://lkml.kernel.org/r/20200127110424.5757-4-david@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
After introducing mem sub section concept, pfn_present() loses its literal
meaning, and will not be necessary a truth on partial populated mem
section.
Since all of the callers use it to judge an absent section, it is better
to rename pfn_present() as pfn_in_present_section().
Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc]
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Leonardo Bras <leonardo@linux.ibm.com>
Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Link: http://lkml.kernel.org/r/1581919110-29575-1-git-send-email-kernelfans@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Patch series "followups to debug_pagealloc improvements through
page_owner", v3.
These are followups to [1] which made it to Linus meanwhile. Patches 1
and 3 are based on Kirill's review, patch 2 on KASAN request [2]. It
would be nice if all of this made it to 5.4 with [1] already there (or
at least Patch 1).
This patch (of 3):
As noted by Kirill, commit 7e2f2a0cd17c ("mm, page_owner: record page
owner for each subpage") has introduced an off-by-one error in
__set_page_owner_handle() when looking up page_ext for subpages. As a
result, the head page page_owner info is set twice, while for the last
tail page, it's not set at all.
Fix this and also make the code more efficient by advancing the page_ext
pointer we already have, instead of calling lookup_page_ext() for each
subpage. Since the full size of struct page_ext is not known at compile
time, we can't use a simple page_ext++ statement, so introduce a
page_ext_next() inline function for that.
Link: http://lkml.kernel.org/r/20190930122916.14969-2-vbabka@suse.cz
Fixes: 7e2f2a0cd17c ("mm, page_owner: record page owner for each subpage")
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reported-by: Kirill A. Shutemov <kirill@shutemov.name>
Reported-by: Miles Chen <miles.chen@mediatek.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Walter Wu <walter-zh.wu@mediatek.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
When debug_pagealloc is enabled, we currently allocate the page_ext
array to mark guard pages with the PAGE_EXT_DEBUG_GUARD flag. Now that
we have the page_type field in struct page, we can use that instead, as
guard pages are neither PageSlab nor mapped to userspace. This reduces
memory overhead when debug_pagealloc is enabled and there are no other
features requiring the page_ext array.
Link: http://lkml.kernel.org/r/20190603143451.27353-4-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
As all the memblock allocation functions return NULL in case of error
rather than panic(), the duplicates with _nopanic suffix can be removed.
Link: http://lkml.kernel.org/r/1548057848-15136-22-git-send-email-rppt@linux.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Petr Mladek <pmladek@suse.com> [printk]
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Christoph Hellwig <hch@lst.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Guo Ren <ren_guo@c-sky.com> [c-sky]
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Juergen Gross <jgross@suse.com> [Xen]
Cc: Mark Salter <msalter@redhat.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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After offlining a memory block, kmemleak scan will trigger a crash, as
it encounters a page ext address that has already been freed during
memory offlining. At the beginning in alloc_page_ext(), it calls
kmemleak_alloc(), but it does not call kmemleak_free() in
free_page_ext().
BUG: unable to handle kernel paging request at ffff888453d00000
PGD 128a01067 P4D 128a01067 PUD 128a04067 PMD 47e09e067 PTE 800ffffbac2ff060
Oops: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI
CPU: 1 PID: 1594 Comm: bash Not tainted 5.0.0-rc8+ #15
Hardware name: HP ProLiant DL180 Gen9/ProLiant DL180 Gen9, BIOS U20 10/25/2017
RIP: 0010:scan_block+0xb5/0x290
Code: 85 6e 01 00 00 48 b8 00 00 30 f5 81 88 ff ff 48 39 c3 0f 84 5b 01 00 00 48 89 d8 48 c1 e8 03 42 80 3c 20 00 0f 85 87 01 00 00 <4c> 8b 3b e8 f3 0c fa ff 4c 39 3d 0c 6b 4c 01 0f 87 08 01 00 00 4c
RSP: 0018:ffff8881ec57f8e0 EFLAGS: 00010082
RAX: 0000000000000000 RBX: ffff888453d00000 RCX: ffffffffa61e5a54
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff888453d00000
RBP: ffff8881ec57f920 R08: fffffbfff4ed588d R09: fffffbfff4ed588c
R10: fffffbfff4ed588c R11: ffffffffa76ac463 R12: dffffc0000000000
R13: ffff888453d00ff9 R14: ffff8881f80cef48 R15: ffff8881f80cef48
FS: 00007f6c0e3f8740(0000) GS:ffff8881f7 |
