kernel/linux
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ synced 2026-10-24 19:10:26 +00:00
Code Issues Releases Packages Activity
No description
1,223,301 commits 117 branches 5,803 tags 5.7 GiB
  • C 96.8%
  • Assembly 0.9%
  • Rust 0.7%
  • Shell 0.6%
  • Python 0.5%
  • Other 0.3%
Find a file
Oleg Nesterov c626db7151 selftests/timers/posix_timers: Reimplement check_timer_distribution() 
[ Upstream commit 6d029c25b7 ]

check_timer_distribution() runs ten threads in a busy loop and tries to
test that the kernel distributes a process posix CPU timer signal to every
thread over time.

There is not guarantee that this is true even after commit bcb7ee7902
("posix-timers: Prefer delivery of signals to the current thread") because
that commit only avoids waking up the sleeping process leader thread, but
that has nothing to do with the actual signal delivery.

As the signal is process wide the first thread which observes sigpending
and wins the race to lock sighand will deliver the signal. Testing shows
that this hangs on a regular base because some threads never win the race.

The comment "This primarily tests that the kernel does not favour any one."
is wrong. The kernel does favour a thread which hits the timer interrupt
when CLOCK_PROCESS_CPUTIME_ID expires.

Rewrite the test so it only checks that the group leader sleeping in join()
never receives SIGALRM and the thread which burns CPU cycles receives all
signals.

In older kernels which do not have commit bcb7ee7902 ("posix-timers:
Prefer delivery of signals to the current thread") the test-case fails
immediately, the very 1st tick wakes the leader up. Otherwise it quickly
succeeds after 100 ticks.

CI testing wants to use newer selftest versions on stable kernels. In this
case the test is guaranteed to fail.

So check in the failure case whether the kernel version is less than v6.3
and skip the test result in that case.

[ tglx: Massaged change log, renamed the version check helper ]

Fixes: e797203fb3 ("selftests/timers/posix_timers: Test delivery of signals across threads")
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240409133802.GD29396@redhat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2024-04-27 17:11:29 +02:00
arch x86/bugs: Replace CONFIG_SPECTRE_BHI_{ON,OFF} with CONFIG_MITIGATION_SPECTRE_BHI 2024-04-17 11:19:37 +02:00
block block: fix q->blkg_list corruption during disk rebind 2024-04-17 11:19:28 +02:00
certs certs: Reference revocation list for all keyrings 2023-08-17 20:12:41 +00:00
crypto crypto: jitter - fix CRYPTO_JITTERENTROPY help text 2024-03-26 18:19:52 -04:00
Documentation x86/bugs: Remove CONFIG_BHI_MITIGATION_AUTO and spectre_bhi=auto 2024-04-17 11:19:37 +02:00
drivers drm/i915: Disable live M/N updates when using bigjoiner 2024-04-27 17:11:29 +02:00
fs smb: client: refresh referral without acquiring refpath_lock 2024-04-27 17:11:28 +02:00
include irqflags: Explicitly ignore lockdep_hrtimer_exit() argument 2024-04-17 11:19:36 +02:00
init init: open /initrd.image with O_LARGEFILE 2024-04-03 15:28:53 +02:00
io_uring io_uring/net: restore msg_control on sendzc retry 2024-04-17 11:19:33 +02:00
ipc Add x86 shadow stack support 2023-08-31 12:20:12 -07:00
kernel x86/cpu: Actually turn off mitigations by default for SPECULATION_MITIGATIONS=n 2024-04-17 11:19:36 +02:00
lib pci_iounmap(): Fix MMIO mapping leak 2024-04-03 15:28:17 +02:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm x86/mm/pat: fix VM_PAT handling in COW mappings 2024-04-10 16:36:03 +02:00
net af_unix: Fix garbage collector racing against connect() 2024-04-17 11:19:32 +02:00
rust rust: upgrade to Rust 1.73.0 2024-02-16 19:10:43 +01:00
samples work around gcc bugs with 'asm goto' with outputs 2024-02-23 09:24:47 +01:00
scripts gcc-plugins/stackleak: Avoid .head.text section 2024-04-13 13:07:40 +02:00
security selinux: avoid dereference of garbage after mount failure 2024-04-10 16:35:48 +02:00
sound ALSA: hda/realtek: Add quirks for some Clevo laptops 2024-04-13 13:07:40 +02:00
tools selftests/timers/posix_timers: Reimplement check_timer_distribution() 2024-04-27 17:11:29 +02:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt KVM: Always flush async #PF workqueue when vCPU is being destroyed 2024-04-03 15:28:18 +02:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.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 MAINTAINERS: add Catherine as xfs maintainer for 6.6.y 2024-02-16 19:10:43 +01:00
Makefile Linux 6.6.28 2024-04-17 11:19:38 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.