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Andrey Ryabinin 6b2cdcc8f5 mm: mempolicy: fix THP allocations escaping mempolicy restrictions commit `3386353406` upstream. alloc_pages_vma() may try to allocate THP page on the local NUMA node first: page = __alloc_pages_node(hpage_node, gfp \| __GFP_THISNODE \| __GFP_NORETRY, order); And if the allocation fails it retries allowing remote memory: if (!page && (gfp & __GFP_DIRECT_RECLAIM)) page = __alloc_pages_node(hpage_node, gfp, order); However, this retry allocation completely ignores memory policy nodemask allowing allocation to escape restrictions. The first appearance of this bug seems to be the commit `ac5b2c1891` ("mm: thp: relax __GFP_THISNODE for MADV_HUGEPAGE mappings"). The bug disappeared later in the commit `89c83fb539` ("mm, thp: consolidate THP gfp handling into alloc_hugepage_direct_gfpmask") and reappeared again in slightly different form in the commit `76e654cc91` ("mm, page_alloc: allow hugepage fallback to remote nodes when madvised") Fix this by passing correct nodemask to the __alloc_pages() call. The demonstration/reproducer of the problem: $ mount -oremount,size=4G,huge=always /dev/shm/ $ echo always > /sys/kernel/mm/transparent_hugepage/defrag $ cat mbind_thp.c #include <unistd.h> #include <sys/mman.h> #include <sys/stat.h> #include <fcntl.h> #include <assert.h> #include <stdlib.h> #include <stdio.h> #include <numaif.h> #define SIZE 2ULL << 30 int main(int argc, char *argv) { int fd; unsigned long long i; char addr; pid_t pid; char buf[100]; unsigned long nodemask = 1; fd = open("/dev/shm/test", O_RDWR\|O_CREAT); assert(fd > 0); assert(ftruncate(fd, SIZE) == 0); addr = mmap(NULL, SIZE, PROT_READ\|PROT_WRITE, MAP_SHARED, fd, 0); assert(mbind(addr, SIZE, MPOL_BIND, &nodemask, 2, MPOL_MF_STRICT\|MPOL_MF_MOVE)==0); for (i = 0; i < SIZE; i+=4096) { addr[i] = 1; } pid = getpid(); snprintf(buf, sizeof(buf), "grep shm /proc/%d/numa_maps", pid); system(buf); sleep(10000); return 0; } $ gcc mbind_thp.c -o mbind_thp -lnuma $ numactl -H available: 2 nodes (0-1) node 0 cpus: 0 2 node 0 size: 1918 MB node 0 free: 1595 MB node 1 cpus: 1 3 node 1 size: 2014 MB node 1 free: 1731 MB node distances: node 0 1 0: 10 20 1: 20 10 $ rm -f /dev/shm/test; taskset -c 0 ./mbind_thp 7fd970a00000 bind:0 file=/dev/shm/test dirty=524288 active=0 N0=396800 N1=127488 kernelpagesize_kB=4 Link: https://lkml.kernel.org/r/20211208165343.22349-1-arbn@yandex-team.com Fixes: `ac5b2c1891` ("mm: thp: relax __GFP_THISNODE for MADV_HUGEPAGE mappings") Signed-off-by: Andrey Ryabinin <arbn@yandex-team.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: David Rientjes <rientjes@google.com> Cc: Andrea Arcangeli <aarcange@redhat.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>		2021-12-29 12:28:58 +01:00
arch	ARM: 9169/1: entry: fix Thumb2 bug in iWMMXt exception handling	2021-12-29 12:28:57 +01:00
block	iocost: Fix divide-by-zero on donation from low hweight cgroup	2021-12-22 09:32:48 +01:00
certs	certs: Add support for using elliptic curve keys for signing modules	2021-08-23 19:55:42 +03:00
crypto	crypto: pcrypt - Delay write to padata->info	2021-11-18 19:16:44 +01:00
Documentation	ALSA: hda/realtek: Add new alc285-hp-amp-init model	2021-12-29 12:28:51 +01:00
drivers	mmc: mmci: stm32: clear DLYB_CR after sending tuning command	2021-12-29 12:28:57 +01:00
fs	ksmbd: disable SMB2_GLOBAL_CAP_ENCRYPTION for SMB 3.1.1	2021-12-29 12:28:57 +01:00
include	tee: handle lookup of shm with reference count 0	2021-12-29 12:28:54 +01:00
init	init: make unknown command line param message clearer	2021-11-18 19:17:11 +01:00
ipc	shm: extend forced shm destroy to support objects from several IPC nses	2021-11-25 09:48:42 +01:00
kernel	kernel/crash_core: suppress unknown crashkernel parameter warning	2021-12-29 12:28:49 +01:00
lib	siphash: use _unaligned version by default	2021-12-08 09:04:47 +01:00
LICENSES	LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes"	2021-07-15 06:31:24 -06:00
mm	mm: mempolicy: fix THP allocations escaping mempolicy restrictions	2021-12-29 12:28:58 +01:00
net	mac80211: fix locking in ieee80211_start_ap error path	2021-12-29 12:28:58 +01:00
samples	samples/bpf: Fix incorrect use of strlen in xdp_redirect_cpu	2021-11-25 09:48:33 +01:00
scripts	recordmcount.pl: look for jgnop instruction as well as bcrl on s390	2021-12-22 09:32:36 +01:00
security	selinux: fix sleeping function called from invalid context	2021-12-22 09:32:47 +01:00
sound	ASoC: tegra: Restore headphones jack name on Nyan Big	2021-12-29 12:28:52 +01:00
tools	selftests: KVM: Fix non-x86 compiling	2021-12-29 12:28:37 +01:00
usr	.gitignore: prefix local generated files with a slash	2021-05-02 00:43:35 +09:00
virt	KVM: downgrade two BUG_ONs to WARN_ON_ONCE	2021-12-22 09:32:34 +01:00
.clang-format	clang-format: Update with the latest for_each macro list	2021-05-12 23:32:39 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore	.gitignore: ignore only top-level modules.builtin	2021-05-02 00:43:35 +09:00
.mailmap	mailmap: add Andrej Shadura	2021-10-18 20:22:03 -10:00
COPYING
CREDITS	MAINTAINERS: Move Daniel Drake to credits	2021-09-21 08:34:58 +03:00
Kbuild
Kconfig	kbuild: ensure full rebuild when the compiler is updated	2020-05-12 13:28:33 +09:00
MAINTAINERS	drm fixes for 5.15 final	2021-10-28 12:17:01 -07:00
Makefile	Linux 5.15.11	2021-12-22 09:32:52 +01:00
README

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.