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Filename Latest commit message Latest commit date
Juergen Gross b56d305274 mm, page_alloc: fix build_zonerefs_node()
commit e553f62f10d93551eb883eca227ac54d1a4fad84 upstream.

Since commit 6aa303defb ("mm, vmscan: only allocate and reclaim from
zones with pages managed by the buddy allocator") only zones with free
memory are included in a built zonelist.  This is problematic when e.g.
all memory of a zone has been ballooned out when zonelists are being
rebuilt.

The decision whether to rebuild the zonelists when onlining new memory
is done based on populated_zone() returning 0 for the zone the memory
will be added to.  The new zone is added to the zonelists only, if it
has free memory pages (managed_zone() returns a non-zero value) after
the memory has been onlined.  This implies, that onlining memory will
always free the added pages to the allocator immediately, but this is
not true in all cases: when e.g. running as a Xen guest the onlined new
memory will be added only to the ballooned memory list, it will be freed
only when the guest is being ballooned up afterwards.

Another problem with using managed_zone() for the decision whether a
zone is being added to the zonelists is, that a zone with all memory
used will in fact be removed from all zonelists in case the zonelists
happen to be rebuilt.

Use populated_zone() when building a zonelist as it has been done before
that commit.

There was a report that QubesOS (based on Xen) is hitting this problem.
Xen has switched to use the zone device functionality in kernel 5.9 and
QubesOS wants to use memory hotplugging for guests in order to be able
to start a guest with minimal memory and expand it as needed.  This was
the report leading to the patch.

Link: https://lkml.kernel.org/r/20220407120637.9035-1-jgross@suse.com
Fixes: 6aa303defb ("mm, vmscan: only allocate and reclaim from zones with pages managed by the buddy allocator")
Signed-off-by: Juergen Gross <jgross@suse.com>
Reported-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-04-20 09:19:38 +02:00
arch powerpc: Fix virt_addr_valid() for 64-bit Book3E & 32-bit 2022-04-20 09:19:37 +02:00
block Revert "Revert "block, bfq: honor already-setup queue merges"" 2022-04-15 14:18:23 +02:00
certs
crypto crypto: authenc - Fix sleep in atomic context in decrypt_tail 2022-04-15 14:18:04 +02:00
Documentation dt-bindings: spi: mxic: The interrupt property is not mandatory 2022-04-15 14:18:30 +02:00
drivers perf/imx_ddr: Fix undefined behavior due to shift overflowing the constant 2022-04-20 09:19:38 +02:00
fs cifs: potential buffer overflow in handling symlinks 2022-04-20 09:19:36 +02:00
include tlb: hugetlb: Add more sizes to tlb_remove_huge_tlb_entry 2022-04-20 09:19:37 +02:00
init init/main.c: return 1 from handled __setup() functions 2022-04-15 14:18:35 +02:00
ipc shm: extend forced shm destroy to support objects from several IPC nses 2021-12-01 09:23:35 +01:00
kernel cgroup: Use open-time cgroup namespace for process migration perm checks 2022-04-15 14:18:41 +02:00
lib lz4: fix LZ4_decompress_safe_partial read out of bound 2022-04-15 14:18:39 +02:00
LICENSES
mm mm, page_alloc: fix build_zonerefs_node() 2022-04-20 09:19:38 +02:00
net nfc: nci: add flush_workqueue to prevent uaf 2022-04-20 09:19:35 +02:00
samples samples/kretprobes: Fix return value if register_kretprobe() failed 2021-11-17 09:48:39 +01:00
scripts gcc-plugins/stackleak: Exactly match strings instead of prefixes 2022-04-15 14:18:22 +02:00
security Fix incorrect type in assignment of ipv6 port for audit 2022-04-15 14:18:22 +02:00
sound ASoC: topology: Allow TLV control to be either read or write 2022-04-15 14:18:30 +02:00
tools testing/selftests/mqueue: Fix mq_perf_tests to free the allocated cpu set 2022-04-20 09:19:35 +02:00
usr
virt KVM: Prevent module exit until all VMs are freed 2022-04-15 14:18:27 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
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Kconfig
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Makefile Linux 5.4.189 2022-04-15 14:18:42 +02:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.