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Thomas Gleixner a23607579f timekeeping: Split jiffies seqlock
[ Upstream commit e5d4d1756b ]

seqlock consists of a sequence counter and a spinlock_t which is used to
serialize the writers. spinlock_t is substituted by a "sleeping" spinlock
on PREEMPT_RT enabled kernels which breaks the usage in the timekeeping
code as the writers are executed in hard interrupt and therefore
non-preemptible context even on PREEMPT_RT.

The spinlock in seqlock cannot be unconditionally replaced by a
raw_spinlock_t as many seqlock users have nesting spinlock sections or
other code which is not suitable to run in truly atomic context on RT.

Instead of providing a raw_seqlock API for a single use case, open code the
seqlock for the jiffies use case and implement it with a raw_spinlock_t and
a sequence counter.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200321113242.120587764@linutronix.de
Stable-dep-of: e9523a0d81 ("tick/common: Align tick period with the HZ tick.")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-05-17 11:35:39 +02:00
arch arm64: kgdb: Set PSTATE.SS to 1 to re-enable single-step 2023-05-17 11:35:39 +02:00
block blk-iocost: fix divide by 0 error in calc_lcoefs() 2023-03-11 16:43:54 +01:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:11:22 +02:00
crypto asymmetric_keys: log on fatal failures in PE/pkcs7 2023-04-20 12:07:36 +02:00
Documentation media: uapi: add MEDIA_BUS_FMT_METADATA_FIXED media bus format. 2023-05-17 11:35:36 +02:00
drivers regulator: stm32-pwr: fix of_iomap leak 2023-05-17 11:35:38 +02:00
fs erofs: fix potential overflow calculating xattr_isize 2023-05-17 11:35:35 +02:00
include media: uapi: add MEDIA_BUS_FMT_METADATA_FIXED media bus format. 2023-05-17 11:35:36 +02:00
init init/Kconfig: fix CC_HAS_ASM_GOTO_TIED_OUTPUT test with dash 2022-12-08 11:22:59 +01:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:23:06 +01:00
kernel timekeeping: Split jiffies seqlock 2023-05-17 11:35:39 +02:00
lib debugobject: Prevent init race with static objects 2023-05-17 11:35:39 +02:00
LICENSES
mm mm/swap: fix swap_info_struct race between swapoff and get_swap_pages() 2023-04-20 12:07:35 +02:00
net bluetooth: Perform careful capability checks in hci_sock_ioctl() 2023-05-17 11:35:31 +02:00
samples samples: vfio-mdev: Fix missing pci_disable_device() in mdpy_fb_probe() 2023-01-18 11:41:26 +01:00
scripts ASN.1: Fix check for strdup() success 2023-04-26 11:24:06 +02:00
security selinux: ensure av_permissions.h is built when needed 2023-05-17 11:35:34 +02:00
sound ASoC: Intel: bytcr_rt5640: Add quirk for the Acer Iconia One 7 B1-750 2023-05-17 11:35:31 +02:00
tools perf sched: Cast PTHREAD_STACK_MIN to int as it may turn into sysconf(__SC_THREAD_STACK_MIN_VALUE) 2023-05-17 11:35:32 +02:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt KVM: Destroy target device if coalesced MMIO unregistration fails 2023-03-11 16:44:01 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS net/phy/mdio-i2c: Move header file to include/linux/mdio 2023-02-06 07:52:46 +01:00
Makefile Linux 5.4.242 2023-04-26 11:24:06 +02:00
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.