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Filename Latest commit message Latest commit date
Gang Li 6264d0fef9 shmem: fix a race between shmem_unused_huge_shrink and shmem_evict_inode
commit 62c9827cbb996c2c04f615ecd783ce28bcea894b upstream.

Fix a data race in commit 779750d20b ("shmem: split huge pages beyond
i_size under memory pressure").

Here are call traces causing race:

   Call Trace 1:
     shmem_unused_huge_shrink+0x3ae/0x410
     ? __list_lru_walk_one.isra.5+0x33/0x160
     super_cache_scan+0x17c/0x190
     shrink_slab.part.55+0x1ef/0x3f0
     shrink_node+0x10e/0x330
     kswapd+0x380/0x740
     kthread+0xfc/0x130
     ? mem_cgroup_shrink_node+0x170/0x170
     ? kthread_create_on_node+0x70/0x70
     ret_from_fork+0x1f/0x30

   Call Trace 2:
     shmem_evict_inode+0xd8/0x190
     evict+0xbe/0x1c0
     do_unlinkat+0x137/0x330
     do_syscall_64+0x76/0x120
     entry_SYSCALL_64_after_hwframe+0x3d/0xa2

A simple explanation:

Image there are 3 items in the local list (@list).  In the first
traversal, A is not deleted from @list.

  1)    A->B->C
        ^
        |
        pos (leave)

In the second traversal, B is deleted from @list.  Concurrently, A is
deleted from @list through shmem_evict_inode() since last reference
counter of inode is dropped by other thread.  Then the @list is corrupted.

  2)    A->B->C
        ^  ^
        |  |
     evict pos (drop)

We should make sure the inode is either on the global list or deleted from
any local list before iput().

Fixed by moving inodes back to global list before we put them.

[akpm@linux-foundation.org: coding style fixes]

Link: https://lkml.kernel.org/r/20211125064502.99983-1-ligang.bdlg@bytedance.com
Fixes: 779750d20b ("shmem: split huge pages beyond i_size under memory pressure")
Signed-off-by: Gang Li <ligang.bdlg@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Hugh Dickins <hughd@google.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>
2022-01-27 09:19:29 +01:00
arch x86/gpu: Reserve stolen memory for first integrated Intel GPU 2022-01-27 09:19:26 +01:00
block block: fix ioprio_get(IOPRIO_WHO_PGRP) vs setuid(2) 2021-12-14 14:49:02 +01:00
certs certs: Trigger creation of RSA module signing key if it's not an RSA key 2021-09-15 09:47:29 +02:00
crypto crypto: pcrypt - Delay write to padata->info 2021-11-17 09:48:40 +01:00
Documentation Input: i8042 - add deferred probe support 2022-01-05 12:37:43 +01:00
drivers PCI: Add function 1 DMA alias quirk for Marvell 88SE9125 SATA controller 2022-01-27 09:19:28 +01:00
fs f2fs: fix to do sanity check in is_alive() 2022-01-27 09:19:26 +01:00
include mm_zone: add function to check if managed dma zone exists 2022-01-27 09:19:28 +01:00
init
ipc shm: extend forced shm destroy to support objects from several IPC nses 2021-12-01 09:23:35 +01:00
kernel perf: Protect perf_guest_cbs with RCU 2022-01-20 09:19:18 +01:00
lib siphash: use _unaligned version by default 2021-12-08 09:01:12 +01:00
LICENSES
mm shmem: fix a race between shmem_unused_huge_shrink and shmem_evict_inode 2022-01-27 09:19:29 +01:00
net nfc: llcp: fix NULL error pointer dereference on sendmsg() after failed bind() 2022-01-27 09:19:26 +01:00
samples samples/kretprobes: Fix return value if register_kretprobe() failed 2021-11-17 09:48:39 +01:00
scripts recordmcount.pl: fix typo in s390 mcount regex 2022-01-05 12:37:44 +01:00
security selinux: initialize proto variable in selinux_ip_postroute_compat() 2022-01-05 12:37:44 +01:00
sound ALSA: hda/realtek - Fix silent output on Gigabyte X570 Aorus Master after reboot from Windows 2022-01-20 09:19:18 +01:00
tools tools/nolibc: fix incorrect truncation of exit code 2022-01-27 09:19:27 +01:00
usr
virt KVM: do not shrink halt_poll_ns below grow_start 2021-10-09 14:39:50 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Linux 5.4.173 2022-01-20 09:19:19 +01:00
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.