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Alexei Starovoitov a033907e7b Merge branch 'Enable RCU semantics for task kptrs' 
David Vernet says:

====================

In commit 22df776a9a ("tasks: Extract rcu_users out of union"), the
'refcount_t rcu_users' field was extracted out of a union with the
'struct rcu_head rcu' field. This allows us to use the field for
refcounting struct task_struct with RCU protection, as the RCU callback
no longer flips rcu_users to be nonzero after the callback is scheduled.

This patch set leverages this to do a few things:

1. Marks struct task_struct as RCU safe in the verifier, allowing
   referenced kptr tasks stored in maps to be accessed in an RCU
   read region without acquiring a reference (with just a NULL check).
2. Makes bpf_task_acquire() a KF_ACQUIRE | KF_RCU | KF_RET_NULL kfunc.
3. Removes bpf_task_kptr_get() and bpf_task_acquire_not_zero(), as
   they're now redundant with the above two changes.
4. Updates selftests and documentation accordingly.
---
Changelog:
v1: https://lore.kernel.org/all/20230331005733.406202-1-void@manifault.com/
v1 -> v2:
- Remove testcases validating nested trust inheritance. The first
  version used 'struct task_struct __rcu *parent', but because that
  field has the __rcu tag it functions differently on gcc and llvm and
  causes gcc selftests to fail. Alexei is reworking nested trust,
  anyways so let's leave it off for now (Alexei).
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-04-01 09:07:21 -07:00
arch bpf-next-for-netdev 2023-03-06 20:36:39 -08:00
block Driver core changes for 6.3-rc1 2023-02-24 12:58:55 -08:00
certs Kbuild updates for v6.3 2023-02-26 11:53:25 -08:00
crypto Networking changes for 6.3. 2023-02-21 18:24:12 -08:00
Documentation bpf,docs: Update documentation to reflect new task kfuncs 2023-04-01 09:07:20 -07:00
drivers bpf: Remove now-unnecessary NULL checks for KF_RELEASE kfuncs 2023-03-25 16:56:22 -07:00
fs ARM: SoC drivers for 6.3 2023-02-27 10:04:49 -08:00
include bpf: Use bpf_mem_cache_alloc/free for bpf_local_storage 2023-03-25 19:52:52 -07:00
init Kbuild updates for v6.3 2023-02-26 11:53:25 -08:00
io_uring net: reclaim skb->scm_io_uring bit 2023-03-08 13:21:47 +00:00
ipc Merge branch 'work.namespace' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2023-02-24 19:20:07 -08:00
kernel bpf: Remove now-defunct task kfuncs 2023-04-01 09:07:20 -07:00
lib Kernel concurrency sanitizer (KCSAN) updates for v6.3 2023-02-25 13:02:20 -08:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm memblock: small optimizations 2023-02-27 09:34:53 -08:00
net bpf: allow a TCP CC to write app_limited 2023-03-29 13:10:56 -07:00
rust Kbuild updates for v6.3 2023-02-26 11:53:25 -08:00
samples bpf: use canonical ftrace path 2023-03-13 21:51:30 -07:00
scripts Kbuild updates for v6.3 2023-02-26 11:53:25 -08:00
security powerpc updates for 6.3 2023-02-25 11:00:06 -08:00
sound ARM: SoC drivers for 6.3 2023-02-27 10:04:49 -08:00
tools bpf: Remove now-defunct task kfuncs 2023-04-01 09:07:20 -07:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt KVM/riscv changes for 6.3 2023-02-15 12:33:28 -05:00
.clang-format media: subdev: Add for_each_active_route() macro 2023-01-22 09:35:57 +01:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for *.dtso files 2023-02-26 15:28:23 +09:00
.gitignore .gitignore: ignore *.cover and *.mbx 2023-02-05 18:51:22 +09:00
.mailmap 12 hotfixes, mostly against mm/. Five of these fixes are cc:stable. 2023-02-13 14:09:20 -08:00
.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 There is no particular theme here - mainly quick hits all over the tree. 2023-02-23 17:55:40 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS ARM: SoC fixes for 6.3, part 1 2023-02-27 10:09:40 -08:00
Makefile Kbuild updates for v6.3 2023-02-26 11:53:25 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.