mirror of
https://github.com/torvalds/linux.git
synced 2024-11-22 20:22:09 +00:00
A mirror of the official Linux kernel repository just in case
2f87d0916c
- Fix ref counter of buffers assigned at boot up A tracing instance can be created from the kernel command line. If it maps to memory, it is considered permanent and should not be deleted, or bad things can happen. If it is not mapped to memory, then the user is fine to delete it via rmdir from the instances directory. But the ref counts assumed 0 was free to remove and greater than zero was not. But this was not the case. When an instance is created, it should have the reference of 1, and if it should not be removed, it must be greater than 1. The boot up code set normal instances with a ref count of 0, which could get removed if something accessed it and then released it. And memory mapped instances had a ref count of 1 which meant it could be deleted, and bad things happen. Keep normal instances ref count as 1, and set memory mapped instances ref count to 2. - Protect sub buffer size (order) updates from other modifications When a ring buffer is changing the size of its sub-buffers, no other operations should be performed on the ring buffer. That includes reading it. But the locking only grabbed the buffer->mutex that keeps some operations from touching the ring buffer. It also must hold the cpu_buffer->reader_lock as well when updates happen as other paths use that to do some operations on the ring buffer. -----BEGIN PGP SIGNATURE----- iIoEABYIADIWIQRRSw7ePDh/lE+zeZMp5XQQmuv6qgUCZw6LSRQccm9zdGVkdEBn b29kbWlzLm9yZwAKCRAp5XQQmuv6qr8NAP4ggN51IEEDLINUctXvTnJAbRdRiZcC Z/q/5hfPS2+uAgEArSfVRCMdCCiVMZv+R9i6YPzn1Ux2OTGbcOHz56lZKgY= =GwKu -----END PGP SIGNATURE----- Merge tag 'trace-ringbuffer-v6.12-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull ring-buffer fixes from Steven Rostedt: - Fix ref counter of buffers assigned at boot up A tracing instance can be created from the kernel command line. If it maps to memory, it is considered permanent and should not be deleted, or bad things can happen. If it is not mapped to memory, then the user is fine to delete it via rmdir from the instances directory. But the ref counts assumed 0 was free to remove and greater than zero was not. But this was not the case. When an instance is created, it should have the reference of 1, and if it should not be removed, it must be greater than 1. The boot up code set normal instances with a ref count of 0, which could get removed if something accessed it and then released it. And memory mapped instances had a ref count of 1 which meant it could be deleted, and bad things happen. Keep normal instances ref count as 1, and set memory mapped instances ref count to 2. - Protect sub buffer size (order) updates from other modifications When a ring buffer is changing the size of its sub-buffers, no other operations should be performed on the ring buffer. That includes reading it. But the locking only grabbed the buffer->mutex that keeps some operations from touching the ring buffer. It also must hold the cpu_buffer->reader_lock as well when updates happen as other paths use that to do some operations on the ring buffer. * tag 'trace-ringbuffer-v6.12-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: ring-buffer: Fix reader locking when changing the sub buffer order ring-buffer: Fix refcount setting of boot mapped buffers |
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| 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.