Commits · cef4493f1aaacf797bc4ab0565682ab1143bf580 · Kirill Smelkov / linux

29 Apr, 2022 40 commits

mm/damon: remove unnecessary type castings · cef4493f

Yu Zhe authored Apr 29, 2022

Remove unnecessary void* type castings.

Link: https://lkml.kernel.org/r/20220421153056.8474-1-yuzhe@nfschina.comSigned-off-by: Yu Zhe <yuzhe@nfschina.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: liqiong <liqiong@nfschina.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

cef4493f

mm/damon/core-test: add a kunit test case for ops registration · 4f540f5a

SeongJae Park authored Apr 29, 2022

This commit adds a simple kunit test case for DAMON operations
registration feature.

Link: https://lkml.kernel.org/r/20220419122225.290518-1-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

4f540f5a

damon: vaddr-test: tweak code to make the logic clearer · 1f4910b3

Xiaomeng Tong authored Apr 29, 2022

Move these two lines into the damon_for_each_region loop, it is always for
testing the last region.  And also avoid to use a list iterator 'r'
outside the loop which is considered harmful[1].

[1]:  https://lkml.org/lkml/2022/2/17/1032

Link: https://lkml.kernel.org/r/20220328115252.31675-1-xiam0nd.tong@gmail.comSigned-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1f4910b3

selftests: cgroup: add a selftest for memory.reclaim · eae3cb2e

Yosry Ahmed authored Apr 29, 2022

Add a new test for memory.reclaim that verifies that the interface
correctly reclaims memory as intended, from both anon and file pages.

Link: https://lkml.kernel.org/r/20220425190040.2475377-5-yosryahmed@google.comSigned-off-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Chen Wandun <chenwandun@huawei.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "Michal Koutn" <mkoutny@suse.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Vaibhav Jain <vaibhav@linux.ibm.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

eae3cb2e

selftests: cgroup: fix alloc_anon_noexit() instantly freeing memory · a3622a53

Yosry Ahmed authored Apr 29, 2022

Currently, alloc_anon_noexit() calls alloc_anon() which instantly frees
the allocated memory. alloc_anon_noexit() is usually used with
cg_run_nowait() to run a process in the background that allocates
memory. It makes sense for the background process to keep the memory
allocated and not instantly free it (otherwise there is no point of
running it in the background).

Link: https://lkml.kernel.org/r/20220425190040.2475377-4-yosryahmed@google.comSigned-off-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Chen Wandun <chenwandun@huawei.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "Michal Koutn" <mkoutny@suse.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Vaibhav Jain <vaibhav@linux.ibm.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

a3622a53

selftests: cgroup: return -errno from cg_read()/cg_write() on failure · 6c26df84

Yosry Ahmed authored Apr 29, 2022

Currently, cg_read()/cg_write() returns 0 on success and -1 on failure.
Modify them to return the -errno on failure.

Link: https://lkml.kernel.org/r/20220425190040.2475377-3-yosryahmed@google.comSigned-off-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Chen Wandun <chenwandun@huawei.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "Michal Koutn" <mkoutny@suse.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Vaibhav Jain <vaibhav@linux.ibm.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

6c26df84

memcg: introduce per-memcg reclaim interface · 94968384

Shakeel Butt authored Apr 29, 2022

This patch series adds a memory.reclaim proactive reclaim interface.
The rationale behind the interface and how it works are in the first
patch.


This patch (of 4):

Introduce a memcg interface to trigger memory reclaim on a memory cgroup.

Use case: Proactive Reclaim
---------------------------

A userspace proactive reclaimer can continuously probe the memcg to
reclaim a small amount of memory.  This gives more accurate and up-to-date
workingset estimation as the LRUs are continuously sorted and can
potentially provide more deterministic memory overcommit behavior.  The
memory overcommit controller can provide more proactive response to the
changing behavior of the running applications instead of being reactive.

A userspace reclaimer's purpose in this case is not a complete replacement
for kswapd or direct reclaim, it is to proactively identify memory savings
opportunities and reclaim some amount of cold pages set by the policy to
free up the memory for more demanding jobs or scheduling new jobs.

A user space proactive reclaimer is used in Google data centers. 
Additionally, Meta's TMO paper recently referenced a very similar
interface used for user space proactive reclaim:
https://dl.acm.org/doi/pdf/10.1145/3503222.3507731

Benefits of a user space reclaimer:
-----------------------------------

1) More flexible on who should be charged for the cpu of the memory
   reclaim.  For proactive reclaim, it makes more sense to be centralized.

2) More flexible on dedicating the resources (like cpu).  The memory
   overcommit controller can balance the cost between the cpu usage and
   the memory reclaimed.

3) Provides a way to the applications to keep their LRUs sorted, so,
   under memory pressure better reclaim candidates are selected.  This
   also gives more accurate and uptodate notion of working set for an
   application.

Why memory.high is not enough?
------------------------------

- memory.high can be used to trigger reclaim in a memcg and can
  potentially be used for proactive reclaim.  However there is a big
  downside in using memory.high.  It can potentially introduce high
  reclaim stalls in the target application as the allocations from the
  processes or the threads of the application can hit the temporary
  memory.high limit.

- Userspace proactive reclaimers usually use feedback loops to decide
  how much memory to proactively reclaim from a workload.  The metrics
  used for this are usually either refaults or PSI, and these metrics will
  become messy if the application gets throttled by hitting the high
  limit.

- memory.high is a stateful interface, if the userspace proactive
  reclaimer crashes for any reason while triggering reclaim it can leave
  the application in a bad state.

- If a workload is rapidly expanding, setting memory.high to proactively
  reclaim memory can result in actually reclaiming more memory than
  intended.

The benefits of such interface and shortcomings of existing interface were
further discussed in this RFC thread:
https://lore.kernel.org/linux-mm/5df21376-7dd1-bf81-8414-32a73cea45dd@google.com/

Interface:
----------

Introducing a very simple memcg interface 'echo 10M > memory.reclaim' to
trigger reclaim in the target memory cgroup.

The interface is introduced as a nested-keyed file to allow for future
optional arguments to be easily added to configure the behavior of
reclaim.

Possible Extensions:
--------------------

- This interface can be extended with an additional parameter or flags
  to allow specifying one or more types of memory to reclaim from (e.g.
  file, anon, ..).

- The interface can also be extended with a node mask to reclaim from
  specific nodes. This has use cases for reclaim-based demotion in memory
  tiering systens.

- A similar per-node interface can also be added to support proactive
  reclaim and reclaim-based demotion in systems without memcg.

- Add a timeout parameter to make it easier for user space to call the
  interface without worrying about being blocked for an undefined amount
  of time.

For now, let's keep things simple by adding the basic functionality.

[yosryahmed@google.com: worked on versions v2 onwards, refreshed to
current master, updated commit message based on recent
discussions and use cases]
Link: https://lkml.kernel.org/r/20220425190040.2475377-1-yosryahmed@google.com
Link: https://lkml.kernel.org/r/20220425190040.2475377-2-yosryahmed@google.comSigned-off-by: Shakeel Butt <shakeelb@google.com>
Co-developed-by: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Wei Xu <weixugc@google.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Zefan Li <lizefan.x@bytedance.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Chen Wandun <chenwandun@huawei.com>
Cc: Vaibhav Jain <vaibhav@linux.ibm.com>
Cc: "Michal Koutn" <mkoutny@suse.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

94968384

zram: add a huge_idle writeback mode · 30226b69

Brian Geffon authored Apr 29, 2022

Today it's only possible to write back as a page, idle, or huge.  A user
might want to writeback pages which are huge and idle first as these idle
pages do not require decompression and make a good first pass for
writeback.

Idle writeback specifically has the advantage that a refault is unlikely
given that the page has been swapped for some amount of time without being
refaulted.

Huge writeback has the advantage that you're guaranteed to get the maximum
benefit from a single page writeback, that is, you're reclaiming one full
page of memory.  Pages which are compressed in zram being written back
result in some benefit which is always less than a page size because of
the fact that it was compressed.

The primary use of this is for minimizing refaults in situations where the
device has to be sensitive to storage endurance.  On ChromeOS we have
devices with slow eMMC and repeated writes and refaults can negatively
affect performance and endurance.

Link: https://lkml.kernel.org/r/20220322215821.1196994-1-bgeffon@google.comSigned-off-by: Brian Geffon <bgeffon@google.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

30226b69

mm/page_alloc: simplify update of pgdat in wake_all_kswapds · d137a7cb

Chen Wandun authored Apr 29, 2022

There is no need to update last_pgdat for each zone, only update
last_pgdat when iterating the first zone of a node.

Link: https://lkml.kernel.org/r/20220322115635.2708989-1-chenwandun@huawei.comSigned-off-by: Chen Wandun <chenwandun@huawei.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

d137a7cb

kasan: mark KASAN_VMALLOC flags as kasan_vmalloc_flags_t · ec2a0f9c

Andrey Konovalov authored Apr 29, 2022

Fix sparse warning:

mm/kasan/shadow.c:496:15: warning: restricted kasan_vmalloc_flags_t degrades to integer

Link: https://lkml.kernel.org/r/52d8fccdd3a48d4bdfd0ff522553bac2a13f1579.1649351254.git.andreyknvl@google.comSigned-off-by: Andrey Konovalov <andreyknvl@google.com>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

ec2a0f9c

kasan: fix sleeping function called from invalid context on RT kernel · 07d067e4

Zqiang authored Apr 29, 2022

BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46
in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 1, name: swapper/0
preempt_count: 1, expected: 0
...........
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.17.1-rt16-yocto-preempt-rt #22
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009),
BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x60/0x8c
dump_stack+0x10/0x12
 __might_resched.cold+0x13b/0x173
rt_spin_lock+0x5b/0xf0
 ___cache_free+0xa5/0x180
qlist_free_all+0x7a/0x160
per_cpu_remove_cache+0x5f/0x70
smp_call_function_many_cond+0x4c4/0x4f0
on_each_cpu_cond_mask+0x49/0xc0
kasan_quarantine_remove_cache+0x54/0xf0
kasan_cache_shrink+0x9/0x10
kmem_cache_shrink+0x13/0x20
acpi_os_purge_cache+0xe/0x20
acpi_purge_cached_objects+0x21/0x6d
acpi_initialize_objects+0x15/0x3b
acpi_init+0x130/0x5ba
do_one_initcall+0xe5/0x5b0
kernel_init_freeable+0x34f/0x3ad
kernel_init+0x1e/0x140
ret_from_fork+0x22/0x30

When the kmem_cache_shrink() was called, the IPI was triggered, the
___cache_free() is called in IPI interrupt context, the local-lock or
spin-lock will be acquired.  On PREEMPT_RT kernel, these locks are
replaced with sleepbale rt-spinlock, so the above problem is triggered. 
Fix it by moving the qlist_free_allfrom() from IPI interrupt context to
task context when PREEMPT_RT is enabled.

[akpm@linux-foundation.org: reduce ifdeffery]
Link: https://lkml.kernel.org/r/20220401134649.2222485-1-qiang1.zhang@intel.comSigned-off-by: Zqiang <qiang1.zhang@intel.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

07d067e4

mm: hugetlb: add missing cache flushing in hugetlb_unshare_all_pmds() · 9c8bbfac

Baolin Wang authored Apr 29, 2022

Missed calling flush_cache_range() before removing the sharing PMD
entrires, otherwise data consistence issue may be occurred on some
architectures whose caches are strict and require a virtual>physical
translation to exist for a virtual address. Thus add it.

Now no architectures enabling PMD sharing will be affected, since they do
not have a VIVT cache. That means this issue can not be happened in
practice so far.

Link: https://lkml.kernel.org/r/47441086affcabb6ecbe403173e9283b0d904b38.1650956489.git.baolin.wang@linux.alibaba.com
Link: https://lkml.kernel.org/r/419b0e777c9e6d1454dcd906e0f5b752a736d335.1650781755.git.baolin.wang@linux.alibaba.com
Fixes: 6dfeaff9 ("hugetlb/userfaultfd: unshare all pmds for hugetlbfs when register wp")
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

9c8bbfac

mm/khugepaged: use vma_is_anonymous · 25fa414a

xu xin authored Apr 29, 2022

Clean up the vma->vm_ops usage. Use vma_is_anonymous instead of
vma->vm_ops to make it more understandable.

Link: https://lkml.kernel.org/r/20220424071642.3234971-1-xu.xin16@zte.com.cnSigned-off-by: xu xin <xu.xin16@zte.com.cn>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

25fa414a

mm: use for_each_online_node and node_online instead of open coding · 30a51400

Peng Liu authored Apr 29, 2022

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.comSigned-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>

30a51400

hugetlb: fix return value of __setup handlers · f81f6e4b

Peng Liu authored Apr 29, 2022

When __setup() return '0', using invalid option values causes the entire
kernel boot option string to be reported as Unknown.  Hugetlb calls
__setup() and will return '0' when set invalid parameter string.

The following phenomenon is observed:
 cmdline:
  hugepagesz=1Y hugepages=1
 dmesg:
  HugeTLB: unsupported hugepagesz=1Y
  HugeTLB: hugepages=1 does not follow a valid hugepagesz, ignoring
  Unknown kernel command line parameters "hugepagesz=1Y hugepages=1"

Since hugetlb will print warning/error information before return for
invalid parameter string, just use return '1' to avoid print again.

Link: https://lkml.kernel.org/r/20220413032915.251254-4-liupeng256@huawei.comSigned-off-by: Peng Liu <liupeng256@huawei.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Liu Yuntao <liuyuntao10@huawei.com>
Cc: Zhenguo Yao <yaozhenguo1@gmail.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

f81f6e4b

hugetlb: fix hugepages_setup when deal with pernode · f87442f4

Peng Liu authored Apr 29, 2022

Hugepages can be specified to pernode since "hugetlbfs: extend the
definition of hugepages parameter to support node allocation", but the
following problem is observed.

Confusing behavior is observed when both 1G and 2M hugepage is set
after "numa=off".
 cmdline hugepage settings:
  hugepagesz=1G hugepages=0:3,1:3
  hugepagesz=2M hugepages=0:1024,1:1024
 results:
  HugeTLB registered 1.00 GiB page size, pre-allocated 0 pages
  HugeTLB registered 2.00 MiB page size, pre-allocated 1024 pages

Furthermore, confusing behavior can be also observed when an invalid node
behind a valid node.  To fix this, never allocate any typical hugepage
when an invalid parameter is received.

Link: https://lkml.kernel.org/r/20220413032915.251254-3-liupeng256@huawei.com
Fixes: b5389086 ("hugetlbfs: extend the definition of hugepages parameter to support node allocation")
Signed-off-by: Peng Liu <liupeng256@huawei.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Liu Yuntao <liuyuntao10@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Zhenguo Yao <yaozhenguo1@gmail.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

f87442f4

hugetlb: fix wrong use of nr_online_nodes · 0a7a0f6f

Peng Liu authored Apr 29, 2022

Patch series "hugetlb: Fix some incorrect behavior", v3.

This series fix three bugs of hugetlb:
1) Invalid use of nr_online_nodes;
2) Inconsistency between 1G hugepage and 2M hugepage;
3) Useless information in dmesg.


This patch (of 4):

Certain systems are designed to have sparse/discontiguous nodes.  In this
case, nr_online_nodes can not be used to walk through numa node.  Also, a
valid node may be greater than nr_online_nodes.

However, in hugetlb, it is assumed that nodes are contiguous.

For sparse/discontiguous nodes, the current code may treat a valid node
as invalid, and will fail to allocate all hugepages on a valid node that
"nid >= nr_online_nodes".

As David suggested:

	if (tmp >= nr_online_nodes)
		goto invalid;

Just imagine node 0 and node 2 are online, and node 1 is offline. 
Assuming that "node < 2" is valid is wrong.  

Recheck all the places that use nr_online_nodes, and repair them one by
one.

[liupeng256@huawei.com: v4]
  Link: https://lkml.kernel.org/r/20220416103526.3287348-1-liupeng256@huawei.com
Link: https://lkml.kernel.org/r/20220413032915.251254-1-liupeng256@huawei.com
Link: https://lkml.kernel.org/r/20220413032915.251254-2-liupeng256@huawei.com
Fixes: 4178158e ("hugetlbfs: fix issue of preallocation of gigantic pages can't work")
Fixes: b5389086 ("hugetlbfs: extend the definition of hugepages parameter to support node allocation")
Fixes: e79ce983 ("hugetlbfs: fix a truncation issue in hugepages parameter")
Fixes: f9317f77 ("hugetlb: clean up potential spectre issue warnings")
Signed-off-by: Peng Liu <liupeng256@huawei.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Zhenguo Yao <yaozhenguo1@gmail.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Liu Yuntao <liuyuntao10@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

0a7a0f6f

drivers/base/memory: fix an unlikely reference counting issue in __add_memory_block() · f47f758c

Christophe JAILLET authored Apr 28, 2022

__add_memory_block() calls both put_device() and device_unregister() when
storing the memory block into the xarray.  This is incorrect because
xarray doesn't take an additional reference and device_unregister()
already calls put_device().

Triggering the issue looks really unlikely and its only effect should be
to log a spurious warning about a ref counted issue.

Link: https://lkml.kernel.org/r/d44c63d78affe844f020dc02ad6af29abc448fc4.1650611702.git.christophe.jaillet@wanadoo.fr
Fixes: 4fb6eabf ("drivers/base/memory.c: cache memory blocks in xarray to accelerate lookup")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Scott Cheloha <cheloha@linux.vnet.ibm.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>