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Paul Gortmaker 96c1fa04f0 tick/rcu: Fix false positive "softirq work is pending" messages 
In commit 0345691b24 ("tick/rcu: Stop allowing RCU_SOFTIRQ in idle") the
new function report_idle_softirq() was created by breaking code out of the
existing can_stop_idle_tick() for kernels v5.18 and newer.

In doing so, the code essentially went from a one conditional:

	if (a && b && c)
		warn();

to a three conditional:

	if (!a)
		return;
	if (!b)
		return;
	if (!c)
		return;
	warn();

But that conversion got the condition for the RT specific
local_bh_blocked() wrong. The original condition was:

   	!local_bh_blocked()

but the conversion failed to negate it so it ended up as:

        if (!local_bh_blocked())
		return false;

This issue lay dormant until another fixup for the same commit was added
in commit a7e282c777 ("tick/rcu: Fix bogus ratelimit condition").
This commit realized the ratelimit was essentially set to zero instead
of ten, and hence *no* softirq pending messages would ever be issued.

Once this commit was backported via linux-stable, both the v6.1 and v6.4
preempt-rt kernels started printing out 10 instances of this at boot:

  NOHZ tick-stop error: local softirq work is pending, handler #80!!!

Remove the negation and return when local_bh_blocked() evaluates to true to
bring the correct behaviour back.

Fixes: 0345691b24 ("tick/rcu: Stop allowing RCU_SOFTIRQ in idle")
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Reviewed-by: Wen Yang <wenyang.linux@foxmail.com>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20230818200757.1808398-1-paul.gortmaker@windriver.com
2023-08-30 12:20:28 +02:00
arch Fix an FPU invalidation bug on exec(), and fix a performance 2023-08-26 10:57:29 -07:00
block block-6.5-2023-08-19 2023-08-19 17:31:46 +02:00
certs KEYS: Add missing function documentation 2023-04-24 16:15:52 +03:00
crypto crypto: fix uninit-value in af_alg_free_resources 2023-08-18 18:30:09 +08:00
Documentation Networking fixes for 6.5-rc8, including fixes from wifi, can 2023-08-24 08:23:13 -07:00
drivers SCSI fixes on 20230827 2023-08-27 07:33:54 -07:00
fs 18 hotfixes. 13 are cc:stable and the remainder pertain to post-6.4 issues 2023-08-25 11:44:43 -07:00
include SCSI fixes on 20230827 2023-08-27 07:33:54 -07:00
init Kbuild updates for v6.5 2023-07-01 09:24:31 -07:00
io_uring io_uring/parisc: Adjust pgoff in io_uring mmap() for parisc 2023-08-08 12:37:01 -06:00
ipc Merge branch 'work.namespace' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2023-02-24 19:20:07 -08:00
kernel tick/rcu: Fix false positive "softirq work is pending" messages 2023-08-30 12:20:28 +02:00
lib lib/clz_ctz.c: Fix __clzdi2() and __ctzdi2() for 32-bit kernels 2023-08-25 13:22:10 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm 18 hotfixes. 13 are cc:stable and the remainder pertain to post-6.4 issues 2023-08-25 11:44:43 -07:00
net Networking fixes for 6.5-rc8, including fixes from wifi, can 2023-08-24 08:23:13 -07:00
rust rust: macros: vtable: fix HAS_* redefinition (gen_const_name) 2023-08-09 21:15:07 +02:00
samples samples: ftrace: Replace bti assembly with hint for older compiler 2023-08-21 22:03:58 -04:00
scripts Kbuild fixes for v6.5 (2nd) 2023-08-13 08:56:24 -07:00
security selinux/stable-6.5 PR 20230821 2023-08-22 10:38:29 -07:00
sound ASoC: Quirk for v6.5 2023-08-25 09:43:49 +02:00
tools 18 hotfixes. 13 are cc:stable and the remainder pertain to post-6.4 issues 2023-08-25 11:44:43 -07:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt KVM: Grab a reference to KVM for VM and vCPU stats file descriptors 2023-07-29 11:05:28 -04:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore Revert ".gitignore: ignore *.cover and *.mbx" 2023-07-04 15:05:12 -07:00
.mailmap mailmap: add entries for Simon Horman 2023-08-16 09:53:10 +01:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING
CREDITS - Address -Wmissing-prototype warnings 2023-06-26 16:43:54 -07:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig
MAINTAINERS sound fixes for 6.5 2023-08-25 08:48:14 -07:00
Makefile Linux 6.5 2023-08-27 14:49:51 -07:00
README

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.