4eeb6535cd
Register/unregister 'mddev->thread' are both under 'reconfig_mutex', however, some context didn't hold the mutex to access mddev->thread, which can cause null-ptr-deference: 1) md_bitmap_daemon_work() can be called from md_check_recovery() where 'reconfig_mutex' is not held, deference 'mddev->thread' might cause null-ptr-deference, because md_unregister_thread() reset the pointer before stopping the thread. 2) timeout_store() access 'mddev->thread' multiple times, null-ptr-deference can be triggered if 'mddev->thread' is reset in the middle. This patch factor out a helper to set timeout, the new helper always check if 'mddev->thread' is null first, so that problem 1 can be fixed. Now that this helper only access 'mddev->thread' once, but it's possible that 'mddev->thread' can be freed while this helper is still in progress, hence the problem is not fixed yet. Follow up patches will fix this by protecting md_thread with rcu. Signed-off-by: Yu Kuai <yukuai3@huawei.com> Signed-off-by: Song Liu <song@kernel.org> Link: https://lore.kernel.org/r/20230523021017.3048783-5-yukuai1@huaweicloud.com |
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| 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 | ||
| .cocciconfig | ||
| .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 Restructured Text 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.