OpenE2K
/
linux
6
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity
874,630 Commits 4 Branches 0 Tags 2 GiB
C 97.7%
Assembly 1.3%
Makefile 0.4%
Shell 0.3%
Python 0.1%
Other 0.1%
Go to file
Yang Shi 366b5dce6d mm: move_pages: return valid node id in status if the page is already on the target node 
commit e0153fc2c7 upstream.

Felix Abecassis reports move_pages() would return random status if the
pages are already on the target node by the below test program:

  int main(void)
  {
	const long node_id = 1;
	const long page_size = sysconf(_SC_PAGESIZE);
	const int64_t num_pages = 8;

	unsigned long nodemask =  1 << node_id;
	long ret = set_mempolicy(MPOL_BIND, &nodemask, sizeof(nodemask));
	if (ret < 0)
		return (EXIT_FAILURE);

	void **pages = malloc(sizeof(void*) * num_pages);
	for (int i = 0; i < num_pages; ++i) {
		pages[i] = mmap(NULL, page_size, PROT_WRITE | PROT_READ,
				MAP_PRIVATE | MAP_POPULATE | MAP_ANONYMOUS,
				-1, 0);
		if (pages[i] == MAP_FAILED)
			return (EXIT_FAILURE);
	}

	ret = set_mempolicy(MPOL_DEFAULT, NULL, 0);
	if (ret < 0)
		return (EXIT_FAILURE);

	int *nodes = malloc(sizeof(int) * num_pages);
	int *status = malloc(sizeof(int) * num_pages);
	for (int i = 0; i < num_pages; ++i) {
		nodes[i] = node_id;
		status[i] = 0xd0; /* simulate garbage values */
	}

	ret = move_pages(0, num_pages, pages, nodes, status, MPOL_MF_MOVE);
	printf("move_pages: %ld\n", ret);
	for (int i = 0; i < num_pages; ++i)
		printf("status[%d] = %d\n", i, status[i]);
  }

Then running the program would return nonsense status values:

  $ ./move_pages_bug
  move_pages: 0
  status[0] = 208
  status[1] = 208
  status[2] = 208
  status[3] = 208
  status[4] = 208
  status[5] = 208
  status[6] = 208
  status[7] = 208

This is because the status is not set if the page is already on the
target node, but move_pages() should return valid status as long as it
succeeds.  The valid status may be errno or node id.

We can't simply initialize status array to zero since the pages may be
not on node 0.  Fix it by updating status with node id which the page is
already on.

Link: http://lkml.kernel.org/r/1575584353-125392-1-git-send-email-yang.shi@linux.alibaba.com
Fixes: a49bd4d716 ("mm, numa: rework do_pages_move")
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Reported-by: Felix Abecassis <fabecassis@nvidia.com>
Tested-by: Felix Abecassis <fabecassis@nvidia.com>
Suggested-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org>	[4.17+]
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>
 		2020-01-09 10:19:57 +01:00
Documentation dt-bindings: Improve validation build error handling 2020-01-04 19:18:11 +01:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
arch mm/memory_hotplug: shrink zones when offlining memory 2020-01-09 10:19:56 +01:00
block block: add bio_truncate to fix guard_bio_eod 2020-01-09 10:19:54 +01:00
certs PKCS#7: Refactor verify_pkcs7_signature() 2019-08-05 18:40:18 -04:00
crypto KEYS: asymmetric: return ENOMEM if akcipher_request_alloc() fails 2019-12-31 16:46:07 +01:00
drivers media: cec: check 'transmit_in_progress', not 'transmitting' 2020-01-09 10:19:56 +01:00
fs block: add bio_truncate to fix guard_bio_eod 2020-01-09 10:19:54 +01:00
include mm/memory_hotplug: shrink zones when offlining memory 2020-01-09 10:19:56 +01:00
init Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-09-28 08:14:15 -07:00
ipc ipc/sem.c: convert to use built-in RCU list checking 2019-09-25 17:51:41 -07:00
kernel memcg: account security cred as well to kmemcg 2020-01-09 10:19:57 +01:00
lib ubsan, x86: Annotate and allow __ubsan_handle_shift_out_of_bounds() in uaccess regions 2019-12-31 16:44:25 +01:00
mm mm: move_pages: return valid node id in status if the page is already on the target node 2020-01-09 10:19:57 +01:00
net netfilter: nft_tproxy: Fix port selector on Big Endian 2020-01-09 10:19:54 +01:00
samples samples: pktgen: fix proc_cmd command result check logic 2019-12-31 16:43:45 +01:00
scripts scripts/kallsyms: fix definitely-lost memory leak 2020-01-04 19:18:23 +01:00
security tomoyo: Don't use nifty names on sockets. 2020-01-04 19:18:42 +01:00
sound ALSA: hda/realtek - Add headset Mic no shutup for ALC283 2020-01-09 10:19:55 +01:00
tools selftests: vm: add fragment CONFIG_TEST_VMALLOC 2020-01-04 19:18:31 +01:00
usr kbuild: update compile-test header list for v5.4-rc2 2019-10-05 15:29:49 +09:00
virt KVM: arm/arm64: Properly handle faulting of device mappings 2019-12-31 16:46:24 +01:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig
…
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap ARM: SoC fixes 2019-11-10 13:41:59 -08:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
Kbuild kbuild: do not descend to ./Kbuild when cleaning 2019-08-21 21:03:58 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-11-22 14:28:14 -08:00
Makefile Linux 5.4.8 2020-01-04 19:19:19 +01:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.