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Andrea Righi ddf7233fca sched/ext: Fix invalid task state transitions on class switch
When enabling a sched_ext scheduler, we may trigger invalid task state
transitions, resulting in warnings like the following (which can be
easily reproduced by running the hotplug selftest in a loop):

 sched_ext: Invalid task state transition 0 -> 3 for fish[770]
 WARNING: CPU: 18 PID: 787 at kernel/sched/ext.c:3862 scx_set_task_state+0x7c/0xc0
 ...
 RIP: 0010:scx_set_task_state+0x7c/0xc0
 ...
 Call Trace:
  <TASK>
  scx_enable_task+0x11f/0x2e0
  switching_to_scx+0x24/0x110
  scx_enable.isra.0+0xd14/0x13d0
  bpf_struct_ops_link_create+0x136/0x1a0
  __sys_bpf+0x1edd/0x2c30
  __x64_sys_bpf+0x21/0x30
  do_syscall_64+0xbb/0x370
  entry_SYSCALL_64_after_hwframe+0x77/0x7f

This happens because we skip initialization for tasks that are already
dead (with their usage counter set to zero), but we don't exclude them
during the scheduling class transition phase.

Fix this by also skipping dead tasks during class swiching, preventing
invalid task state transitions.

Fixes: a8532fac7b ("sched_ext: TASK_DEAD tasks must be switched into SCX on ops_enable")
Cc: stable@vger.kernel.org # v6.12+
Signed-off-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-08-11 06:56:37 -10:00
arch - Fix an interrupt vector setup race which leads to a non-functioning device 2025-08-10 08:15:32 +03:00
block block-6.17-20250808 2025-08-09 08:47:28 +03:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto Significant patch series in this pull request: 2025-08-03 16:23:09 -07:00
Documentation EFI updates for v6.17 2025-08-09 18:10:01 +03:00
drivers - Fix a wrong ioremap size in mvebu-gicp 2025-08-10 08:46:47 +03:00
fs NFS client updates for Linux 6.17 2025-08-09 07:20:44 +03:00
include TTY revert fix for 6.16-rc1 2025-08-09 18:12:23 +03:00
init Significant patch series in this pull request: 2025-08-03 16:23:09 -07:00
io_uring io_uring/memmap: cast nr_pages to size_t before shifting 2025-08-08 06:35:14 -06:00
ipc vfs-6.17-rc1.mmap_prepare 2025-07-28 13:43:25 -07:00
kernel sched/ext: Fix invalid task state transitions on class switch 2025-08-11 06:56:37 -10:00
lib block-6.17-20250808 2025-08-09 08:47:28 +03:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
mm Significant patch series in this pull request: 2025-08-05 16:02:07 +03:00
net NFS client updates for Linux 6.17 2025-08-09 07:20:44 +03:00
rust Rust changes for v6.17 2025-08-03 13:49:10 -07:00
samples Significant patch series in this pull request: 2025-08-03 16:23:09 -07:00
scripts Kbuild updates for v6.17 2025-08-06 07:32:52 +03:00
security + Features 2025-08-04 08:17:28 -07:00
sound gpio updates for v6.17-rc1 2025-08-09 08:15:43 +03:00
tools tools/power turbostat: version 2025.09.09 2025-08-10 09:02:36 +03:00
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 scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.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 Significant patch series in this pull request: 2025-08-03 16:23:09 -07:00
.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 COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS Kbuild updates for v6.17 2025-08-06 07:32:52 +03:00
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 spi: Fixes for v6.17 2025-08-09 08:43:24 +03:00
Makefile Linux 6.17-rc1 2025-08-10 19:41:16 +03:00
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.