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Miaohe Lin 198932a14a mm/mempolicy: fix mpol_new leak in shared_policy_replace
commit 4ad099559b upstream.

If mpol_new is allocated but not used in restart loop, mpol_new will be
freed via mpol_put before returning to the caller.  But refcnt is not
initialized yet, so mpol_put could not do the right things and might
leak the unused mpol_new.  This would happen if mempolicy was updated on
the shared shmem file while the sp->lock has been dropped during the
memory allocation.

This issue could be triggered easily with the below code snippet if
there are many processes doing the below work at the same time:

  shmid = shmget((key_t)5566, 1024 * PAGE_SIZE, 0666|IPC_CREAT);
  shm = shmat(shmid, 0, 0);
  loop many times {
    mbind(shm, 1024 * PAGE_SIZE, MPOL_LOCAL, mask, maxnode, 0);
    mbind(shm + 128 * PAGE_SIZE, 128 * PAGE_SIZE, MPOL_DEFAULT, mask,
          maxnode, 0);
  }

Link: https://lkml.kernel.org/r/20220329111416.27954-1-linmiaohe@huawei.com
Fixes: 42288fe366 ("mm: mempolicy: Convert shared_policy mutex to spinlock")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: <stable@vger.kernel.org>	[3.8]
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>
2022-04-13 20:59:22 +02:00
arch arm64: Add part number for Arm Cortex-A78AE 2022-04-13 20:59:20 +02:00
block block: Fix the maximum minor value is blk_alloc_ext_minor() 2022-04-08 14:24:11 +02:00
certs certs: Add support for using elliptic curve keys for signing modules 2021-08-23 19:55:42 +03:00
crypto crypto: xts - Add softdep on ecb 2022-04-08 14:23:55 +02:00
Documentation docs: sysctl/kernel: add missing bit to panic_print 2022-04-08 14:24:16 +02:00
drivers mmc: core: Fixup support for writeback-cache for eMMC and SD 2022-04-13 20:59:21 +02:00
fs io_uring: don't touch scm_fp_list after queueing skb 2022-04-13 20:59:20 +02:00
include rtc: mc146818-lib: fix RTC presence check 2022-04-13 20:59:14 +02:00
init init/main.c: return 1 from handled __setup() functions 2022-04-13 20:59:10 +02:00
ipc ipc/sem: do not sleep with a spin lock held 2022-02-08 18:34:03 +01:00
kernel swiotlb: Support aligned swiotlb buffers 2022-04-08 14:24:17 +02:00
lib lz4: fix LZ4_decompress_safe_partial read out of bound 2022-04-13 20:59:21 +02:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm mm/mempolicy: fix mpol_new leak in shared_policy_replace 2022-04-13 20:59:22 +02:00
net SUNRPC: svc_tcp_sendmsg() should handle errors from xdr_alloc_bvec() 2022-04-13 20:59:20 +02:00
samples samples/bpf, xdpsock: Fix race when running for fix duration of time 2022-04-08 14:23:40 +02:00
scripts modpost: restore the warning message for missing symbol versions 2022-04-08 14:24:10 +02:00
security Fix incorrect type in assignment of ipv6 port for audit 2022-04-08 14:23:55 +02:00
sound ASoC: topology: Allow TLV control to be either read or write 2022-04-08 14:24:15 +02:00
tools perf session: Remap buf if there is no space for event 2022-04-13 20:59:20 +02:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:27:15 +01:00
virt KVM: Prevent module exit until all VMs are freed 2022-04-08 14:24:07 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.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 COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: adjust file entry for of_net.c after movement 2022-03-08 19:12:53 +01:00
Makefile Linux 5.15.33 2022-04-08 14:24:18 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.