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Qais Yousef 37481ad72d sched/uclamp: Fix locking around cpu_util_update_eff()
[ Upstream commit 93b73858701fd01de26a4a874eb95f9b7156fd4b ]

cpu_cgroup_css_online() calls cpu_util_update_eff() without holding the
uclamp_mutex or rcu_read_lock() like other call sites, which is
a mistake.

The uclamp_mutex is required to protect against concurrent reads and
writes that could update the cgroup hierarchy.

The rcu_read_lock() is required to traverse the cgroup data structures
in cpu_util_update_eff().

Surround the caller with the required locks and add some asserts to
better document the dependency in cpu_util_update_eff().

Fixes: 7226017ad3 ("sched/uclamp: Fix a bug in propagating uclamp value in new cgroups")
Reported-by: Quentin Perret <qperret@google.com>
Signed-off-by: Qais Yousef <qais.yousef@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210510145032.1934078-3-qais.yousef@arm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14 16:56:03 +02:00
arch ia64: mca_drv: fix incorrect array size calculation 2021-07-14 16:56:02 +02:00
block block: fix discard request merge 2021-07-14 16:56:02 +02:00
certs certs: Add ability to preload revocation certs 2021-06-30 08:47:30 -04:00
crypto crypto: shash - avoid comparing pointers to exported functions under CFI 2021-07-14 16:55:54 +02:00
Documentation clocksource: Retry clock read if long delays detected 2021-07-14 16:56:01 +02:00
drivers media: I2C: change 'RST' to "RSET" to fix multiple build errors 2021-07-14 16:56:03 +02:00
fs writeback, cgroup: increment isw_nr_in_flight before grabbing an inode 2021-07-14 16:56:02 +02:00
include clocksource: Check per-CPU clock synchronization when marked unstable 2021-07-14 16:56:01 +02:00
init sched/core: Initialize the idle task with preemption disabled 2021-07-14 16:55:50 +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 sched/uclamp: Fix locking around cpu_util_update_eff() 2021-07-14 16:56:03 +02:00
lib lib: vsprintf: Fix handling of number field widths in vsscanf 2021-07-14 16:55:57 +02:00
LICENSES LICENSES/deprecated: add Zlib license text 2020-09-16 14:33:49 +02:00
mm mm/gup: fix try_grab_compound_head() race with split_huge_page() 2021-07-14 16:55:42 +02:00
net SUNRPC: Should wake up the privileged task firstly. 2021-07-14 16:55:42 +02:00
samples samples: vfio-mdev: fix error handing in mdpy_fb_probe() 2021-06-10 13:39:15 +02:00
scripts Makefile: fix GDB warning with CONFIG_RELR 2021-07-14 16:55:53 +02:00
security evm: Refuse EVM_ALLOW_METADATA_WRITES only if an HMAC key is loaded 2021-07-14 16:55:46 +02:00
sound ALSA: hda/realtek: fix mute/micmute LEDs for HP EliteBook 830 G8 Notebook PC 2021-07-14 16:55:37 +02:00
tools selftests/lkdtm: Avoid needing explicit sub-shell 2021-07-14 16:55:38 +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: do not allow mapping valid but non-reference-counted pages 2021-06-30 08:47:25 -04:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
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.gitignore kbuild: generate Module.symvers only when vmlinux exists 2021-05-19 10:12:59 +02:00
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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 f2fs: move ioctl interface definitions to separated file 2021-05-19 10:13:00 +02:00
Makefile Makefile: fix GDB warning with CONFIG_RELR 2021-07-14 16:55:53 +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.