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The linux-next integration testing tree
7f8ca0edfe
PRIO_PGRP needs the tasklist_lock mainly to serialize vs setpgid(2), to protect against any concurrent change_pid(PIDTYPE_PGID) that can move the task from one hlist to another while iterating. However, the remaining can only rely only on RCU: PRIO_PROCESS only does the task lookup and never iterates over tasklist and we already have an rcu-aware stable pointer. PRIO_USER is already racy vs setuid(2) so with creds being rcu protected, we can end up seeing stale data. When removing the tasklist_lock there can be a race with (i) fork but this is benign as the child's nice is inherited and the new task is not observable by the user yet either, hence the return semantics do not differ. And (ii) a race with exit, which is a small window and can cause us to miss a task which was removed from the list and it had the highest nice. Similarly change the buggy do_each_thread/while_each_thread combo in PRIO_USER for the rcu-safe for_each_process_thread flavor, which doesn't make use of next_thread/p->thread_group. [akpm@linux-foundation.org: coding style fixes] Link: https://lkml.kernel.org/r/20211210182250.43734-1-dave@stgolabs.net Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| 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 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.