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Kumar Kartikeya Dwivedi 15cf39221e selftests/bpf: Add stress test for rqspinlock in NMI
Introduce a kernel module that will exercise lock acquisition in the NMI
path, and bias toward creating contention such that NMI waiters end up
being non-head waiters. Prior to the rqspinlock fix made in the commit
0d80e7f951 ("rqspinlock: Choose trylock fallback for NMI waiters"), it
was possible for the queueing path of non-head waiters to get stuck in
NMI, which this stress test reproduces fairly easily with just 3 CPUs.

Both AA and ABBA flavors are supported, and it will serve as a test case
for future fixes that address this corner case. More information about
the problem in question is available in the commit cited above. When the
fix is reverted, this stress test will lock up the system.

To enable this test automatically through the test_progs infrastructure,
add a load_module_params API to exercise both AA and ABBA cases when
running the test.

Note that the test runs for at most 5 seconds, and becomes a noop after
that, in order to allow the system to make forward progress. In
addition, CPU 0 is always kept untouched by the created threads and
NMIs. The test will automatically scale to the number of available
online CPUs.

Note that at least 3 CPUs are necessary to run this test, hence skip the
selftest in case the environment has less than 3 CPUs available.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20250927205304.199760-1-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-09-28 03:18:40 -07:00
arch riscv: bpf: Fix uninitialized symbol 'retval_off' 2025-09-23 12:29:03 -07:00
block vfs-6.17-rc6.fixes 2025-09-08 07:53:01 -07:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto bpf: Implement signature verification for BPF programs 2025-09-22 18:58:03 -07:00
Documentation bpf: disable and remove registers chain based liveness 2025-09-19 09:27:23 -07:00
drivers Power management fixes for 6.17-rc6 2025-09-11 08:11:16 -07:00
fs for-6.17-rc5-tag 2025-09-11 08:01:18 -07:00
include bpf: Enforce expected_attach_type for tailcall compatibility 2025-09-27 06:24:27 -07:00
init 20 hotfixes. 15 are cc:stable and the remainder address post-6.16 issues 2025-09-10 21:19:34 -07:00
io_uring vfs-6.17-rc6.fixes 2025-09-08 07:53:01 -07:00
ipc vfs-6.17-rc1.mmap_prepare 2025-07-28 13:43:25 -07:00
kernel bpf: Enforce expected_attach_type for tailcall compatibility 2025-09-27 06:24:27 -07:00
lib hardening fixes for v6.17-rc4 2025-08-31 08:56:45 -07:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
mm 20 hotfixes. 15 are cc:stable and the remainder address post-6.16 issues 2025-09-10 21:19:34 -07:00
net bpf: Emit struct bpf_xdp_sock type in vmlinux BTF 2025-09-25 14:29:46 -07:00
rust Rust fixes for v6.17 (2nd) 2025-09-06 12:33:09 -07:00
samples ftrace/samples: Fix function size computation 2025-09-05 18:39:12 -04:00
scripts Rust fixes for v6.17 (2nd) 2025-09-06 12:33:09 -07:00
security + Features 2025-08-04 08:17:28 -07:00
sound ALSA: hda/hdmi: Add pin fix for another HP EliteDesk 800 G4 model 2025-09-01 13:51:57 +02:00
tools selftests/bpf: Add stress test for rqspinlock in NMI 2025-09-28 03:18:40 -07:00
usr usr/include: openrisc: don't HDRTEST bpf_perf_event.h 2025-05-12 15:03:17 +09:00
virt Merge tag 'kvm-x86-no_assignment-6.17' of https://github.com/kvm-x86/linux into HEAD 2025-07-29 08:36:42 -04:00
.clang-format Linux 6.15-rc5 2025-05-06 16:39:25 +10:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +02:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: Retire Ralf Baechle 2024-11-12 15:48:59 +01:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore gitignore: allow .pylintrc to be tracked 2025-07-02 17:10:04 -06:00
.mailmap MAINTAINERS: Update Nobuhiro Iwamatsu's email address 2025-09-01 10:36:10 +02:00
.pylintrc docs: add a .pylintrc file with sys path for docs scripts 2025-04-09 12:10:33 -06:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING
CREDITS MAINTAINERS: Delete inactive maintainers from AF_XDP 2025-09-25 13:18:22 +02:00
Kbuild drm: ensure drm headers are self-contained and pass kernel-doc 2025-02-12 10:44:43 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS MAINTAINERS: Delete inactive maintainers from AF_XDP 2025-09-25 13:18:22 +02:00
Makefile Linux 6.17-rc5 2025-09-07 14:22:57 -07:00
README README: Fix spelling 2024-03-18 03:36:32 -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 reStructuredText 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.