mirror of https://github.com/torvalds/linux.git
6c8ad3ab45
raw_spin_locks can be traced by lockdep or tracing itself. Atomic64
operations can be used in the tracing infrastructure. When an architecture
does not have true atomic64 operations it can use the generic version that
disables interrupts and uses spin_locks.
The tracing ring buffer code uses atomic64 operations for the time
keeping. But because some architectures use the default operations, the
locking inside the atomic operations can cause an infinite recursion.
As atomic64 implementation is architecture specific, it should not be
using raw_spin_locks() but instead arch_spin_locks as that is the purpose
of arch_spin_locks. To be used in architecture specific implementations of
generic infrastructure like atomic64 operations.
Note, by switching from raw_spin_locks to arch_spin_locks, the locks taken
to emulate the atomic64 operations will not have lockdep, mmio, or any
kind of checks done on them. They will not even disable preemption,
although the code will disable interrupts preventing the tasks that hold
the locks from being preempted. As the locks held are done so for very
short periods of time, and the logic is only done to emulate atomic64, not
having them be instrumented should not be an issue.
Cc: stable@vger.kernel.org
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andreas Larsson <andreas@gaisler.com>
Link: https://lore.kernel.org/20250122144311.64392baf@gandalf.local.home
Fixes:
|
||
|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| 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 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.