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Linus Torvalds dba3ec9f2a Updates for the interrupt core subsystem:
- Prevent a interrupt migration related live lock in handle_edge_irq()
 
     If the interrupt affinity is moved to a new target CPU and the
     interrupt is currently handled on the previous target CPU for edge type
     interrupts the handler might get stuck on the previous target for a
     long time, which causes both involved CPUs to waste cycles and
     eventually run into a soft-lockup situation.
 
     Solve this by checking whether the interrupt is redirected to a new
     target CPU and if the interrupt is handled on that new target CPU, busy
     wait for completion instead of masking it and sending the pending but
     which would cause the old CPU to re-run the handler and in the worst
     case repeating this excercise for a long time.
 
     This only works on architectures which use single CPU interrupt
     targets, but that's so far the only ones where this behaviour has been
     observed.
 
   - Add a kunit test for interrupt disable depth counts
 
     The nested interrupt disable depth has been an issue in the past
     especially vs. free_irq(), interrupt shutdown and CPU hotplug and their
     interactions. The test exercises the combinations of these scenarios
     and checks for correctness.
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Merge tag 'irq-core-2025-07-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull irq updates from Thomas Gleixner:

 - Prevent a interrupt migration related live lock in handle_edge_irq()

   If the interrupt affinity is moved to a new target CPU and the
   interrupt is currently handled on the previous target CPU for edge
   type interrupts the handler might get stuck on the previous target
   for a long time, which causes both involved CPUs to waste cycles and
   eventually run into a soft-lockup situation.

   Solve this by checking whether the interrupt is redirected to a new
   target CPU and if the interrupt is handled on that new target CPU,
   busy wait for completion instead of masking it and sending the
   pending but which would cause the old CPU to re-run the handler and
   in the worst case repeating this excercise for a long time.

   This only works on architectures which use single CPU interrupt
   targets, but that's so far the only ones where this behaviour has
   been observed.

 - Add a kunit test for interrupt disable depth counts

   The nested interrupt disable depth has been an issue in the past
   especially vs. free_irq(), interrupt shutdown and CPU hotplug and
   their interactions. The test exercises the combinations of these
   scenarios and checks for correctness.

* tag 'irq-core-2025-07-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq: Prevent migration live lock in handle_edge_irq()
  genirq: Split up irq_pm_check_wakeup()
  genirq: Move irq_wait_for_poll() to call site
  genirq: Remove pointless local variable
  genirq: Add kunit tests for depth counts
2025-07-29 12:55:12 -07:00
arch Driver core changes for 6.17-rc1 2025-07-29 12:15:39 -07:00
block Driver core changes for 6.17-rc1 2025-07-29 12:15:39 -07:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto Crypto library updates for 6.17 2025-07-28 17:58:52 -07:00
Documentation linux_kselftest-kunit-6.17-rc1 2025-07-29 12:43:10 -07:00
drivers A trivial cleanup in the PCI/MSI code to remove a duplicated back and forth 2025-07-29 12:52:06 -07:00
fs Driver core changes for 6.17-rc1 2025-07-29 12:15:39 -07:00
include linux_kselftest-kunit-6.17-rc1 2025-07-29 12:43:10 -07:00
init Char / Misc / IIO / other driver updates for 6.17-rc1 2025-07-29 09:52:01 -07:00
io_uring for-6.17/io_uring-20250728 2025-07-28 16:30:12 -07:00
ipc vfs-6.17-rc1.mmap_prepare 2025-07-28 13:43:25 -07:00
kernel Updates for the interrupt core subsystem: 2025-07-29 12:55:12 -07:00
lib linux_kselftest-kunit-6.17-rc1 2025-07-29 12:43:10 -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 Driver core changes for 6.17-rc1 2025-07-29 12:15:39 -07:00
net Driver core changes for 6.17-rc1 2025-07-29 12:15:39 -07:00
rust Driver core changes for 6.17-rc1 2025-07-29 12:15:39 -07:00
samples Driver core changes for 6.17-rc1 2025-07-29 12:15:39 -07:00
scripts Driver core changes for 6.17-rc1 2025-07-29 12:15:39 -07:00
security Landlock update for v6.17-rc1 2025-07-28 19:21:32 -07:00
sound ASoC: Updates for v6.17 2025-07-24 14:47:49 +02:00
tools linux_kselftest-next-6.17-rc1 2025-07-29 12:48:53 -07:00
usr usr/include: openrisc: don't HDRTEST bpf_perf_event.h 2025-05-12 15:03:17 +09:00
virt KVM: Allow CPU to reschedule while setting per-page memory attributes 2025-06-24 12:20:17 -07:00
.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: ignore Python compiled bytecode 2025-04-24 10:12:46 -06:00
.mailmap 11 hotfixes. 9 are cc:stable and the remainder address post-6.15 issues 2025-07-24 19:13:30 -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 mm: update MAINTAINERS entry for HMM 2025-07-19 19:26:16 -07:00
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 Driver core changes for 6.17-rc1 2025-07-29 12:15:39 -07:00
Makefile hardening updates for v6.17-rc1 2025-07-28 17:16:12 -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.