<feed xmlns='http://www.w3.org/2005/Atom'>
<title>BMC/Intel-BMC/linux.git/mm, branch dev-5.14-intel</title>
<subtitle>Intel OpenBMC Linux kernel source tree (mirror)</subtitle>
<id>https://git.radix-linux.su/BMC/Intel-BMC/linux.git/atom?h=dev-5.14-intel</id>
<link rel='self' href='https://git.radix-linux.su/BMC/Intel-BMC/linux.git/atom?h=dev-5.14-intel'/>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/BMC/Intel-BMC/linux.git/'/>
<updated>2021-10-07T05:53:19+00:00</updated>
<entry>
<title>mm: don't allow oversized kvmalloc() calls</title>
<updated>2021-10-07T05:53:19+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-07-14T16:45:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/BMC/Intel-BMC/linux.git/commit/?id=24f3fc95b56b9df7cad82d8553b7fc86f9461fd1'/>
<id>urn:sha1:24f3fc95b56b9df7cad82d8553b7fc86f9461fd1</id>
<content type='text'>
commit 7661809d493b426e979f39ab512e3adf41fbcc69 upstream.

'kvmalloc()' is a convenience function for people who want to do a
kmalloc() but fall back on vmalloc() if there aren't enough physically
contiguous pages, or if the allocation is larger than what kmalloc()
supports.

However, let's make sure it doesn't get _too_ easy to do crazy things
with it.  In particular, don't allow big allocations that could be due
to integer overflow or underflow.  So make sure the allocation size fits
in an 'int', to protect against trivial integer conversion issues.

Acked-by: Willy Tarreau &lt;w@1wt.eu&gt;
Cc: Kees Cook &lt;keescook@chromium.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>mm: fix uninitialized use in overcommit_policy_handler</title>
<updated>2021-09-30T08:12:52+00:00</updated>
<author>
<name>Chen Jun</name>
<email>chenjun102@huawei.com</email>
</author>
<published>2021-09-24T22:44:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/BMC/Intel-BMC/linux.git/commit/?id=9c93c402c467db1cd2a219e182a19e345f46be6a'/>
<id>urn:sha1:9c93c402c467db1cd2a219e182a19e345f46be6a</id>
<content type='text'>
commit bcbda81020c3ee77e2c098cadf3e84f99ca3de17 upstream.

We get an unexpected value of /proc/sys/vm/overcommit_memory after
running the following program:

  int main()
  {
      int fd = open("/proc/sys/vm/overcommit_memory", O_RDWR);
      write(fd, "1", 1);
      write(fd, "2", 1);
      close(fd);
  }

write(fd, "2", 1) will pass *ppos = 1 to proc_dointvec_minmax.
proc_dointvec_minmax will return 0 without setting new_policy.

  t.data = &amp;new_policy;
  ret = proc_dointvec_minmax(&amp;t, write, buffer, lenp, ppos)
      --&gt;do_proc_dointvec
         --&gt;__do_proc_dointvec
              if (write) {
                if (proc_first_pos_non_zero_ignore(ppos, table))
                  goto out;

  sysctl_overcommit_memory = new_policy;

so sysctl_overcommit_memory will be set to an uninitialized value.

Check whether new_policy has been changed by proc_dointvec_minmax.

Link: https://lkml.kernel.org/r/20210923020524.13289-1-chenjun102@huawei.com
Fixes: 56f3547bfa4d ("mm: adjust vm_committed_as_batch according to vm overcommit policy")
Signed-off-by: Chen Jun &lt;chenjun102@huawei.com&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Reviewed-by: Feng Tang &lt;feng.tang@intel.com&gt;
Reviewed-by: Kefeng Wang &lt;wangkefeng.wang@huawei.com&gt;
Cc: Rui Xiang &lt;rui.xiang@huawei.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>mm/debug: sync up MR_CONTIG_RANGE and MR_LONGTERM_PIN</title>
<updated>2021-09-30T08:12:52+00:00</updated>
<author>
<name>Weizhao Ouyang</name>
<email>o451686892@gmail.com</email>
</author>
<published>2021-09-24T22:43:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/BMC/Intel-BMC/linux.git/commit/?id=a7032c95c6e8ddedebbe307a8011d61cc832f01c'/>
<id>urn:sha1:a7032c95c6e8ddedebbe307a8011d61cc832f01c</id>
<content type='text'>
commit a4ce73910427e960b2c7f4d83229153c327d0ee7 upstream.

Sync up MR_CONTIG_RANGE and MR_LONGTERM_PIN to migrate_reason_names.

Link: https://lkml.kernel.org/r/20210921064553.293905-2-o451686892@gmail.com
Fixes: 310253514bbf ("mm/migrate: rename migration reason MR_CMA to MR_CONTIG_RANGE")
Fixes: d1e153fea2a8 ("mm/gup: migrate pinned pages out of movable zone")
Signed-off-by: Weizhao Ouyang &lt;o451686892@gmail.com&gt;
Reviewed-by: "Huang, Ying" &lt;ying.huang@intel.com&gt;
Reviewed-by: John Hubbard &lt;jhubbard@nvidia.com&gt;
Cc: Anshuman Khandual &lt;khandual@linux.vnet.ibm.com&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Pavel Tatashin &lt;pasha.tatashin@soleen.com&gt;
Cc: Yang Shi &lt;yang.shi@linux.alibaba.com&gt;
Cc: Zi Yan &lt;ziy@nvidia.com&gt;
Cc: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Cc: Minchan Kim &lt;minchan@kernel.org&gt;
Cc: Mina Almasry &lt;almasrymina@google.com&gt;
Cc: "Matthew Wilcox (Oracle)" &lt;willy@infradead.org&gt;
Cc: Oscar Salvador &lt;osalvador@suse.de&gt;
Cc: Wei Xu &lt;weixugc@google.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>mm, hwpoison: add is_free_buddy_page() in HWPoisonHandlable()</title>
<updated>2021-09-30T08:12:52+00:00</updated>
<author>
<name>Naoya Horiguchi</name>
<email>naoya.horiguchi@nec.com</email>
</author>
<published>2021-09-24T22:43:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/BMC/Intel-BMC/linux.git/commit/?id=0414a521d1eaf00eacfc20ae9a47797d11faae1b'/>
<id>urn:sha1:0414a521d1eaf00eacfc20ae9a47797d11faae1b</id>
<content type='text'>
commit acfa299a4a63a58e5e81a87cb16798f20d35f7d7 upstream.

Commit fcc00621d88b ("mm/hwpoison: retry with shake_page() for
unhandlable pages") changed the return value of __get_hwpoison_page() to
retry for transiently unhandlable cases.  However, __get_hwpoison_page()
currently fails to properly judge buddy pages as handlable, so hard/soft
offline for buddy pages always fail as "unhandlable page".  This is
totally regrettable.

So let's add is_free_buddy_page() in HWPoisonHandlable(), so that
__get_hwpoison_page() returns different return values between buddy
pages and unhandlable pages as intended.

Link: https://lkml.kernel.org/r/20210909004131.163221-1-naoya.horiguchi@linux.dev
Fixes: fcc00621d88b ("mm/hwpoison: retry with shake_page() for unhandlable pages")
Signed-off-by: Naoya Horiguchi &lt;naoya.horiguchi@nec.com&gt;
Acked-by: David Hildenbrand &lt;david@redhat.com&gt;
Reviewed-by: Yang Shi &lt;shy828301@gmail.com&gt;
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Cc: Oscar Salvador &lt;osalvador@suse.de&gt;
Cc: Mike Kravetz &lt;mike.kravetz@oracle.com&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>mm/mempolicy: fix a race between offset_il_node and mpol_rebind_task</title>
<updated>2021-09-18T11:44:02+00:00</updated>
<author>
<name>yanghui</name>
<email>yanghui.def@bytedance.com</email>
</author>
<published>2021-09-09T01:10:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/BMC/Intel-BMC/linux.git/commit/?id=02cd61fa3e5921bf26da29a74cc9e1ec9de0d286'/>
<id>urn:sha1:02cd61fa3e5921bf26da29a74cc9e1ec9de0d286</id>
<content type='text'>
commit 276aeee1c5fc00df700f0782060beae126600472 upstream.

Servers happened below panic:

  Kernel version:5.4.56
  BUG: unable to handle page fault for address: 0000000000002c48
  RIP: 0010:__next_zones_zonelist+0x1d/0x40
  Call Trace:
    __alloc_pages_nodemask+0x277/0x310
    alloc_page_interleave+0x13/0x70
    handle_mm_fault+0xf99/0x1390
    __do_page_fault+0x288/0x500
    do_page_fault+0x30/0x110
    page_fault+0x3e/0x50

The reason for the panic is that MAX_NUMNODES is passed in the third
parameter in __alloc_pages_nodemask(preferred_nid).  So access to
zonelist-&gt;zoneref-&gt;zone_idx in __next_zones_zonelist will cause a panic.

In offset_il_node(), first_node() returns nid from pol-&gt;v.nodes, after
this other threads may chang pol-&gt;v.nodes before next_node().  This race
condition will let next_node return MAX_NUMNODES.  So put pol-&gt;nodes in
a local variable.

The race condition is between offset_il_node and cpuset_change_task_nodemask:

  CPU0:                                     CPU1:
  alloc_pages_vma()
    interleave_nid(pol,)
      offset_il_node(pol,)
        first_node(pol-&gt;v.nodes)            cpuset_change_task_nodemask
                        //nodes==0xc          mpol_rebind_task
                                                mpol_rebind_policy
                                                  mpol_rebind_nodemask(pol,nodes)
                        //nodes==0x3
        next_node(nid, pol-&gt;v.nodes)//return MAX_NUMNODES

Link: https://lkml.kernel.org/r/20210906034658.48721-1-yanghui.def@bytedance.com
Signed-off-by: yanghui &lt;yanghui.def@bytedance.com&gt;
Reviewed-by: Muchun Song &lt;songmuchun@bytedance.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>mm/page_alloc.c: avoid accessing uninitialized pcp page migratetype</title>
<updated>2021-09-18T11:44:02+00:00</updated>
<author>
<name>Miaohe Lin</name>
<email>linmiaohe@huawei.com</email>
</author>
<published>2021-09-09T01:10:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/BMC/Intel-BMC/linux.git/commit/?id=40298f33aa3197316e8bce40b5c34882bc01e718'/>
<id>urn:sha1:40298f33aa3197316e8bce40b5c34882bc01e718</id>
<content type='text'>
commit 053cfda102306a3394012f9fe2594811c34925e4 upstream.

If it's not prepared to free unref page, the pcp page migratetype is
unset.  Thus we will get rubbish from get_pcppage_migratetype() and
might list_del(&amp;page-&gt;lru) again after it's already deleted from the list
leading to grumble about data corruption.

Link: https://lkml.kernel.org/r/20210902115447.57050-1-linmiaohe@huawei.com
Fixes: df1acc856923 ("mm/page_alloc: avoid conflating IRQs disabled with zone-&gt;lock")
Signed-off-by: Miaohe Lin &lt;linmiaohe@huawei.com&gt;
Acked-by: Mel Gorman &lt;mgorman@techsingularity.net&gt;
Acked-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Reviewed-by: David Hildenbrand &lt;david@redhat.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>mm,vmscan: fix divide by zero in get_scan_count</title>
<updated>2021-09-18T11:44:02+00:00</updated>
<author>
<name>Rik van Riel</name>
<email>riel@surriel.com</email>
</author>
<published>2021-09-09T01:10:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/BMC/Intel-BMC/linux.git/commit/?id=d8f8f8c8f3692e7529c0386ab7741c17a57e83cd'/>
<id>urn:sha1:d8f8f8c8f3692e7529c0386ab7741c17a57e83cd</id>
<content type='text'>
commit 32d4f4b782bb8f0ceb78c6b5dc46eb577ae25bf7 upstream.

Commit f56ce412a59d ("mm: memcontrol: fix occasional OOMs due to
proportional memory.low reclaim") introduced a divide by zero corner
case when oomd is being used in combination with cgroup memory.low
protection.

When oomd decides to kill a cgroup, it will force the cgroup memory to
be reclaimed after killing the tasks, by writing to the memory.max file
for that cgroup, forcing the remaining page cache and reclaimable slab
to be reclaimed down to zero.

Previously, on cgroups with some memory.low protection that would result
in the memory being reclaimed down to the memory.low limit, or likely
not at all, having the page cache reclaimed asynchronously later.

With f56ce412a59d the oomd write to memory.max tries to reclaim all the
way down to zero, which may race with another reclaimer, to the point of
ending up with the divide by zero below.

This patch implements the obvious fix.

Link: https://lkml.kernel.org/r/20210826220149.058089c6@imladris.surriel.com
Fixes: f56ce412a59d ("mm: memcontrol: fix occasional OOMs due to proportional memory.low reclaim")
Signed-off-by: Rik van Riel &lt;riel@surriel.com&gt;
Acked-by: Roman Gushchin &lt;guro@fb.com&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Acked-by: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Acked-by: Chris Down &lt;chris@chrisdown.name&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>mm/hmm: bypass devmap pte when all pfn requested flags are fulfilled</title>
<updated>2021-09-18T11:44:02+00:00</updated>
<author>
<name>Li Zhijian</name>
<email>lizhijian@cn.fujitsu.com</email>
</author>
<published>2021-09-09T01:10:02+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/BMC/Intel-BMC/linux.git/commit/?id=9f8a2ed8875fe7b60bf18eaf11a78191d8659d54'/>
<id>urn:sha1:9f8a2ed8875fe7b60bf18eaf11a78191d8659d54</id>
<content type='text'>
commit 4b42fb213678d2b6a9eeea92a9be200f23e49583 upstream.

Previously, we noticed the one rpma example was failed[1] since commit
36f30e486dce ("IB/core: Improve ODP to use hmm_range_fault()"), where it
will use ODP feature to do RDMA WRITE between fsdax files.

After digging into the code, we found hmm_vma_handle_pte() will still
return EFAULT even though all the its requesting flags has been
fulfilled.  That's because a DAX page will be marked as (_PAGE_SPECIAL |
PAGE_DEVMAP) by pte_mkdevmap().

Link: https://github.com/pmem/rpma/issues/1142 [1]
Link: https://lkml.kernel.org/r/20210830094232.203029-1-lizhijian@cn.fujitsu.com
Fixes: 405506274922 ("mm/hmm: add missing call to hmm_pte_need_fault in HMM_PFN_SPECIAL handling")
Signed-off-by: Li Zhijian &lt;lizhijian@cn.fujitsu.com&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Jason Gunthorpe &lt;jgg@nvidia.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>mm/memory_hotplug: use "unsigned long" for PFN in zone_for_pfn_range()</title>
<updated>2021-09-18T11:44:02+00:00</updated>
<author>
<name>David Hildenbrand</name>
<email>david@redhat.com</email>
</author>
<published>2021-09-08T02:54:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/BMC/Intel-BMC/linux.git/commit/?id=65c7cdc921b8eb13300b8c722f8c4096cced68ef'/>
<id>urn:sha1:65c7cdc921b8eb13300b8c722f8c4096cced68ef</id>
<content type='text'>
commit 7cf209ba8a86410939a24cb1aeb279479a7e0ca6 upstream.

Patch series "mm/memory_hotplug: preparatory patches for new online policy and memory"

These are all cleanups and one fix previously sent as part of [1]:
[PATCH v1 00/12] mm/memory_hotplug: "auto-movable" online policy and memory
groups.

These patches make sense even without the other series, therefore I pulled
them out to make the other series easier to digest.

[1] https://lkml.kernel.org/r/20210607195430.48228-1-david@redhat.com

This patch (of 4):

Checkpatch complained on a follow-up patch that we are using "unsigned"
here, which defaults to "unsigned int" and checkpatch is correct.

As we will search for a fitting zone using the wrong pfn, we might end
up onlining memory to one of the special kernel zones, such as ZONE_DMA,
which can end badly as the onlined memory does not satisfy properties of
these zones.

Use "unsigned long" instead, just as we do in other places when handling
PFNs.  This can bite us once we have physical addresses in the range of
multiple TB.

Link: https://lkml.kernel.org/r/20210712124052.26491-2-david@redhat.com
Fixes: e5e689302633 ("mm, memory_hotplug: display allowed zones in the preferred ordering")
Signed-off-by: David Hildenbrand &lt;david@redhat.com&gt;
Reviewed-by: Pankaj Gupta &lt;pankaj.gupta@ionos.com&gt;
Reviewed-by: Muchun Song &lt;songmuchun@bytedance.com&gt;
Reviewed-by: Oscar Salvador &lt;osalvador@suse.de&gt;
Cc: David Hildenbrand &lt;david@redhat.com&gt;
Cc: Vitaly Kuznetsov &lt;vkuznets@redhat.com&gt;
Cc: "Michael S. Tsirkin" &lt;mst@redhat.com&gt;
Cc: Jason Wang &lt;jasowang@redhat.com&gt;
Cc: Pankaj Gupta &lt;pankaj.gupta.linux@gmail.com&gt;
Cc: Wei Yang &lt;richard.weiyang@linux.alibaba.com&gt;
Cc: Michal Hocko &lt;mhocko@kernel.org&gt;
Cc: Dan Williams &lt;dan.j.williams@intel.com&gt;
Cc: Anshuman Khandual &lt;anshuman.khandual@arm.com&gt;
Cc: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Cc: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: Mike Rapoport &lt;rppt@kernel.org&gt;
Cc: "Rafael J. Wysocki" &lt;rjw@rjwysocki.net&gt;
Cc: Len Brown &lt;lenb@kernel.org&gt;
Cc: Pavel Tatashin &lt;pasha.tatashin@soleen.com&gt;
Cc: Heiko Carstens &lt;hca@linux.ibm.com&gt;
Cc: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: virtualization@lists.linux-foundation.org
Cc: Andy Lutomirski &lt;luto@kernel.org&gt;
Cc: "Aneesh Kumar K.V" &lt;aneesh.kumar@linux.ibm.com&gt;
Cc: Anton Blanchard &lt;anton@ozlabs.org&gt;
Cc: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Cc: Baoquan He &lt;bhe@redhat.com&gt;
Cc: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Cc: Borislav Petkov &lt;bp@alien8.de&gt;
Cc: Christian Borntraeger &lt;borntraeger@de.ibm.com&gt;
Cc: Christophe Leroy &lt;christophe.leroy@c-s.fr&gt;
Cc: Dave Jiang &lt;dave.jiang@intel.com&gt;
Cc: "H. Peter Anvin" &lt;hpa@zytor.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Jia He &lt;justin.he@arm.com&gt;
Cc: Joe Perches &lt;joe@perches.com&gt;
Cc: Kefeng Wang &lt;wangkefeng.wang@huawei.com&gt;
Cc: Laurent Dufour &lt;ldufour@linux.ibm.com&gt;
Cc: Michel Lespinasse &lt;michel@lespinasse.org&gt;
Cc: Nathan Lynch &lt;nathanl@linux.ibm.com&gt;
Cc: Nicholas Piggin &lt;npiggin@gmail.com&gt;
Cc: Paul Mackerras &lt;paulus@samba.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Pierre Morel &lt;pmorel@linux.ibm.com&gt;
Cc: "Rafael J. Wysocki" &lt;rafael.j.wysocki@intel.com&gt;
Cc: Rich Felker &lt;dalias@libc.org&gt;
Cc: Scott Cheloha &lt;cheloha@linux.ibm.com&gt;
Cc: Sergei Trofimovich &lt;slyfox@gentoo.org&gt;
Cc: Thiago Jung Bauermann &lt;bauerman@linux.ibm.com&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
Cc: Vishal Verma &lt;vishal.l.verma@intel.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Cc: Yoshinori Sato &lt;ysato@users.sourceforge.jp&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>hugetlb: fix hugetlb cgroup refcounting during vma split</title>
<updated>2021-09-18T11:44:02+00:00</updated>
<author>
<name>Mike Kravetz</name>
<email>mike.kravetz@oracle.com</email>
</author>
<published>2021-09-02T21:58:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/BMC/Intel-BMC/linux.git/commit/?id=e25b227e947498c6d51d1ed08470752a8a1a7783'/>
<id>urn:sha1:e25b227e947498c6d51d1ed08470752a8a1a7783</id>
<content type='text'>
commit 09a26e832705fdb7a9484495b71a05e0bbc65207 upstream.

Guillaume Morin reported hitting the following WARNING followed by GPF or
NULL pointer deference either in cgroups_destroy or in the kill_css path.:

    percpu ref (css_release) &lt;= 0 (-1) after switching to atomic
    WARNING: CPU: 23 PID: 130 at lib/percpu-refcount.c:196 percpu_ref_switch_to_atomic_rcu+0x127/0x130
    CPU: 23 PID: 130 Comm: ksoftirqd/23 Kdump: loaded Tainted: G           O      5.10.60 #1
    RIP: 0010:percpu_ref_switch_to_atomic_rcu+0x127/0x130
    Call Trace:
       rcu_core+0x30f/0x530
       rcu_core_si+0xe/0x10
       __do_softirq+0x103/0x2a2
       run_ksoftirqd+0x2b/0x40
       smpboot_thread_fn+0x11a/0x170
       kthread+0x10a/0x140
       ret_from_fork+0x22/0x30

Upon further examination, it was discovered that the css structure was
associated with hugetlb reservations.

For private hugetlb mappings the vma points to a reserve map that
contains a pointer to the css.  At mmap time, reservations are set up
and a reference to the css is taken.  This reference is dropped in the
vma close operation; hugetlb_vm_op_close.  However, if a vma is split no
additional reference to the css is taken yet hugetlb_vm_op_close will be
called twice for the split vma resulting in an underflow.

Fix by taking another reference in hugetlb_vm_op_open.  Note that the
reference is only taken for the owner of the reserve map.  In the more
common fork case, the pointer to the reserve map is cleared for
non-owning vmas.

Link: https://lkml.kernel.org/r/20210830215015.155224-1-mike.kravetz@oracle.com
Fixes: e9fe92ae0cd2 ("hugetlb_cgroup: add reservation accounting for private mappings")
Signed-off-by: Mike Kravetz &lt;mike.kravetz@oracle.com&gt;
Reported-by: Guillaume Morin &lt;guillaume@morinfr.org&gt;
Suggested-by: Guillaume Morin &lt;guillaume@morinfr.org&gt;
Tested-by: Guillaume Morin &lt;guillaume@morinfr.org&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
</feed>
