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Peter Zijlstra 08beb0d436 x86: Fix CPUIDLE_FLAG_IRQ_ENABLE leaking timer reprogram
[ Upstream commit edc8fc01f6 ]

intel_idle_irq() re-enables IRQs very early. As a result, an interrupt
may fire before mwait() is eventually called. If such an interrupt queues
a timer, it may go unnoticed until mwait returns and the idle loop
handles the tick re-evaluation. And monitoring TIF_NEED_RESCHED doesn't
help because a local timer enqueue doesn't set that flag.

The issue is mitigated by the fact that this idle handler is only invoked
for shallow C-states when, presumably, the next tick is supposed to be
close enough. There may still be rare cases though when the next tick
is far away and the selected C-state is shallow, resulting in a timer
getting ignored for a while.

Fix this with using sti_mwait() whose IRQ-reenablement only triggers
upon calling mwait(), dealing with the race while keeping the interrupt
latency within acceptable bounds.

Fixes: c227233ad6 (intel_idle: enable interrupts before C1 on Xeons)
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lkml.kernel.org/r/20231115151325.6262-3-frederic@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-01-25 15:35:12 -08:00
arch x86: Fix CPUIDLE_FLAG_IRQ_ENABLE leaking timer reprogram 2024-01-25 15:35:12 -08:00
block blk-mq: don't count completed flush data request as inflight in case of quiesce 2024-01-20 11:51:39 +01:00
certs certs: Reference revocation list for all keyrings 2023-08-17 20:12:41 +00:00
crypto crypto: xts - use 'spawn' for underlying single-block cipher 2024-01-10 17:16:54 +01:00
Documentation dt-bindings: nvmem: mxs-ocotp: Document fsl,ocotp 2024-01-01 12:42:42 +00:00
drivers x86: Fix CPUIDLE_FLAG_IRQ_ENABLE leaking timer reprogram 2024-01-25 15:35:12 -08:00
fs ksmbd: free ppace array on error in parse_dacl 2024-01-20 11:51:48 +01:00
include driver core: Add a guard() definition for the device_lock() 2024-01-20 11:51:44 +01:00
init proc: sysctl: prevent aliased sysctls from getting passed to init 2023-11-28 17:19:57 +00:00
io_uring io_uring: use fget/fput consistently 2024-01-20 11:51:38 +01:00
ipc Add x86 shadow stack support 2023-08-31 12:20:12 -07:00
kernel posix-timers: Get rid of [COMPAT_]SYS_NI() uses 2024-01-20 11:51:46 +01:00
lib ida: Fix crash in ida_free when the bitmap is empty 2024-01-20 11:51:46 +01:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm/memory_hotplug: fix memmap_on_memory sysfs value retrieval 2024-01-20 11:51:49 +01:00
net net: qrtr: ns: Return 0 if server port is not present 2024-01-20 11:51:47 +01:00
rust rust: docs: fix logo replacement 2023-10-19 16:40:00 +02:00
samples vfio/mtty: Overhaul mtty interrupt handling 2024-01-10 17:16:55 +01:00
scripts scripts/decode_stacktrace.sh: optionally use LLVM utilities 2024-01-20 11:51:49 +01:00
security apparmor: Fix move_mount mediation by detecting if source is detached 2024-01-10 17:16:52 +01:00
sound ASoC: SOF: Intel: hda-codec: Delay the codec device registration 2024-01-20 11:51:47 +01:00
tools kselftest: alsa: fixed a print formatting warning 2024-01-20 11:51:45 +01:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt ARM: 2023-09-07 13:52:20 -07:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: rpm-pkg: rename binkernel.spec to kernel.spec 2023-07-25 00:59:33 +09:00
.mailmap 20 hotfixes. 12 are cc:stable and the remainder address post-6.5 issues 2023-10-24 09:52:16 -10:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS USB: Remove Wireless USB and UWB documentation 2023-08-09 14:17:32 +02:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Char/Misc driver fixes for 6.6-final 2023-10-28 07:51:27 -10:00
Makefile Linux 6.6.13 2024-01-20 11:51:49 +01:00
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.