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Tejun Heo 3868314882 cgroup: statically initialize init_css_set->dfl_cgrp
Like other csets, init_css_set's dfl_cgrp is initialized when the cset
gets linked.  init_css_set gets linked in cgroup_init().  This has
been fine till now but the recently added basic CPU usage accounting
may end up accessing dfl_cgrp of init before cgroup_init() leading to
the following oops.

  SELinux:  Initializing.
  BUG: unable to handle kernel NULL pointer dereference at 00000000000000b0
  IP: account_system_index_time+0x60/0x90
  PGD 0 P4D 0
  Oops: 0000 [#1] SMP
  Modules linked in:
  CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.14.0-rc2-00003-g041cd64 #10
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
  +1.9.3-20161025_171302-gandalf 04/01/2014
  task: ffffffff81e10480 task.stack: ffffffff81e00000
  RIP: 0010:account_system_index_time+0x60/0x90
  RSP: 0000:ffff880011e03cb8 EFLAGS: 00010002
  RAX: ffffffff81ef8800 RBX: ffffffff81e10480 RCX: 0000000000000003
  RDX: 0000000000000000 RSI: 00000000000f4240 RDI: 0000000000000000
  RBP: ffff880011e03cc0 R08: 0000000000010000 R09: 0000000000000000
  R10: 0000000000000020 R11: 0000003b9aca0000 R12: 000000000001c100
  R13: 0000000000000000 R14: ffffffff81e10480 R15: ffffffff81e03cd8
  FS:  0000000000000000(0000) GS:ffff880011e00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00000000000000b0 CR3: 0000000001e09000 CR4: 00000000000006b0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  Call Trace:
   <IRQ>
   account_system_time+0x45/0x60
   account_process_tick+0x5a/0x140
   update_process_times+0x22/0x60
   tick_periodic+0x2b/0x90
   tick_handle_periodic+0x25/0x70
   timer_interrupt+0x15/0x20
   __handle_irq_event_percpu+0x7e/0x1b0
   handle_irq_event_percpu+0x23/0x60
   handle_irq_event+0x42/0x70
   handle_level_irq+0x83/0x100
   handle_irq+0x6f/0x110
   do_IRQ+0x46/0xd0
   common_interrupt+0x9d/0x9d

Fix it by statically initializing init_css_set.dfl_cgrp so that init's
default cgroup is accessible from the get-go.

Fixes: 041cd640b2 ("cgroup: Implement cgroup2 basic CPU usage accounting")
Reported-by: “kbuild-all@01.org” <kbuild-all@01.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
2017-09-25 14:02:53 -07:00
arch Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-09-24 12:33:58 -07:00
block block: directly insert blk-mq request from blk_insert_cloned_request() 2017-09-11 16:43:57 -06:00
certs modsign: add markers to endif-statements in certs/Makefile 2017-07-14 11:01:37 +10:00
crypto crypto: af_alg - update correct dst SGL entry 2017-09-20 17:42:42 +08:00
Documentation cgroup: Implement cgroup2 basic CPU usage accounting 2017-09-25 08:12:05 -07:00
drivers Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-09-24 12:28:55 -07:00
firmware firmware: Restore support for built-in firmware 2017-09-16 10:58:48 -07:00
fs Various SMB3 fixes for stable and security improvements from the recently completed SMB3/Samba test events 2017-09-22 16:11:48 -10:00
include cgroup: Implement cgroup2 basic CPU usage accounting 2017-09-25 08:12:05 -07:00
init Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-09-14 18:54:01 -07:00
ipc ipc/shm: Fix order of parameters when calling copy_compat_shmid_to_user 2017-09-20 23:27:48 -04:00
kernel cgroup: statically initialize init_css_set->dfl_cgrp 2017-09-25 14:02:53 -07:00
lib Merge branch 'parisc-4.14-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux 2017-09-23 06:14:06 -10:00
mm Merge branch 'work.read_write' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-09-14 19:29:55 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-09-23 05:41:27 -10:00
samples media updates for v4.14-rc1 2017-09-07 12:53:14 -07:00
scripts DeviceTree fixes for 4.14: 2017-09-24 16:04:12 -07:00
security Merge branch 'next-general' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2017-09-24 11:40:41 -07:00
sound vfs: constify path argument to kernel_read_file_from_path 2017-09-14 20:18:45 -07:00
tools Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-09-24 12:33:58 -07:00
usr ramfs: clarify help text that compression applies to ramfs as well as legacy ramdisk. 2017-07-06 16:24:30 -07:00
virt Revert "KVM: Don't accept obviously wrong gsi values via KVM_IRQFD" 2017-09-19 08:37:17 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap power supply and reset changes for the v4.12 series (part 2) 2017-05-12 12:02:21 -07:00
COPYING
CREDITS selinux/stable-4.14 PR 20170831 2017-09-12 13:21:00 -07:00
Kbuild kbuild: Consolidate header generation from ASM offset information 2017-04-13 05:43:37 +09:00
Kconfig
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-09-23 05:41:27 -10:00
Makefile Linux 4.14-rc2 2017-09-24 16:38:56 -07:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

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

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

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.