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Tejun Heo 0dc644018d blk-iocost: fix operation ordering in iocg_wake_fn()
commit 5ab189cf3abbc9994bae3be524c5b88589ed56e2 upstream.

iocg_wake_fn() open-codes wait_queue_entry removal and wakeup because it
wants the wq_entry to be always removed whether it ended up waking the
task or not. finish_wait() tests whether wq_entry needs removal without
grabbing the wait_queue lock and expects the waker to use
list_del_init_careful() after all waking operations are complete, which
iocg_wake_fn() didn't do. The operation order was wrong and the regular
list_del_init() was used.

The result is that if a waiter wakes up racing the waker, it can free pop
the wq_entry off stack before the waker is still looking at it, which can
lead to a backtrace like the following.

  [7312084.588951] general protection fault, probably for non-canonical address 0x586bf4005b2b88: 0000 [#1] SMP
  ...
  [7312084.647079] RIP: 0010:queued_spin_lock_slowpath+0x171/0x1b0
  ...
  [7312084.858314] Call Trace:
  [7312084.863548]  _raw_spin_lock_irqsave+0x22/0x30
  [7312084.872605]  try_to_wake_up+0x4c/0x4f0
  [7312084.880444]  iocg_wake_fn+0x71/0x80
  [7312084.887763]  __wake_up_common+0x71/0x140
  [7312084.895951]  iocg_kick_waitq+0xe8/0x2b0
  [7312084.903964]  ioc_rqos_throttle+0x275/0x650
  [7312084.922423]  __rq_qos_throttle+0x20/0x30
  [7312084.930608]  blk_mq_make_request+0x120/0x650
  [7312084.939490]  generic_make_request+0xca/0x310
  [7312084.957600]  submit_bio+0x173/0x200
  [7312084.981806]  swap_readpage+0x15c/0x240
  [7312084.989646]  read_swap_cache_async+0x58/0x60
  [7312084.998527]  swap_cluster_readahead+0x201/0x320
  [7312085.023432]  swapin_readahead+0x2df/0x450
  [7312085.040672]  do_swap_page+0x52f/0x820
  [7312085.058259]  handle_mm_fault+0xa16/0x1420
  [7312085.066620]  do_page_fault+0x2c6/0x5c0
  [7312085.074459]  page_fault+0x2f/0x40

Fix it by switching to list_del_init_careful() and putting it at the end.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Rik van Riel <riel@surriel.com>
Fixes: 7caa47151a ("blkcg: implement blk-iocost")
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-07-05 18:03:16 +02:00
arch alpha: register early reserved memory in memblock 2024-07-05 18:03:15 +02:00
block blk-iocost: fix operation ordering in iocg_wake_fn() 2024-07-05 18:03:16 +02:00
certs certs: add 'x509_revocation_list' to gitignore 2021-07-20 16:05:35 +02:00
crypto init: add dsm gpl source 2024-07-05 18:00:04 +02:00
Documentation init: add dsm gpl source 2024-07-05 18:00:04 +02:00
drivers drm/amdgpu: Fix resource leak on probe error path 2024-07-05 18:03:16 +02:00
fs ocfs2: issue zeroout to EOF blocks 2024-07-05 18:03:15 +02:00
include init: add dsm gpl source 2024-07-05 18:00:04 +02:00
init init: add dsm gpl source 2024-07-05 18:00:04 +02:00
ipc ipc/mqueue, msg, sem: avoid relying on a stack reference past its expiry 2021-05-26 12:06:54 +02:00
kernel init: add dsm gpl source 2024-07-05 18:00:04 +02:00
lib init: add dsm gpl source 2024-07-05 18:00:04 +02:00
LICENSES LICENSES/deprecated: add Zlib license text 2020-09-16 14:33:49 +02:00
mm init: add dsm gpl source 2024-07-05 18:00:04 +02:00
net can: raw: raw_setsockopt(): fix raw_rcv panic for sock UAF 2024-07-05 18:03:15 +02:00
samples samples/bpf: Fix the error return code of xdp_redirect's main() 2021-07-14 16:56:23 +02:00
scripts init: add dsm gpl source 2024-07-05 18:00:04 +02:00
security init: add dsm gpl source 2024-07-05 18:00:04 +02:00
sound ALSA: pcm: Fix mmap capability check 2021-07-28 14:35:43 +02:00
SynoBuildConf init: add dsm gpl source 2024-07-05 18:00:04 +02:00
synology init: add dsm gpl source 2024-07-05 18:00:04 +02:00
tools init: add dsm gpl source 2024-07-05 18:00:04 +02:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt KVM: add missing compat KVM_CLEAR_DIRTY_LOG 2024-07-05 18:03:15 +02:00
.clang-format init: add dsm gpl source 2024-07-05 18:00:04 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.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 kbuild: generate Module.symvers only when vmlinux exists 2021-05-19 10:12:59 +02:00
.mailmap mailmap: add two more addresses of Uwe Kleine-König 2020-12-06 10:19:07 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Jason Cooper to CREDITS 2020-11-30 10:20:34 +01:00
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 init: add dsm gpl source 2024-07-05 18:00:04 +02:00
Makefile init: add dsm gpl source 2024-07-05 18:00:04 +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.