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Andrii Nakryiko bc308d011a libbpf: call dup2() syscall directly
We've ran into issues with using dup2() API in production setting, where
libbpf is linked into large production environment and ends up calling
unintended custom implementations of dup2(). These custom implementations
don't provide atomic FD replacement guarantees of dup2() syscall,
leading to subtle and hard to debug issues.

To prevent this in the future and guarantee that no libc implementation
will do their own custom non-atomic dup2() implementation, call dup2()
syscall directly with syscall(SYS_dup2).

Note that some architectures don't seem to provide dup2 and have dup3
instead. Try to detect and pick best syscall.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Song Liu <song@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20240119210201.1295511-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-01-23 15:13:47 -08:00
arch bpf, arm64: Enable the inline of bpf_kptr_xchg() 2024-01-23 15:11:23 -08:00
block for-6.8/block-2024-01-08 2024-01-11 13:58:04 -08:00
certs This update includes the following changes: 2023-11-02 16:15:30 -10:00
crypto crypto: scomp - fix req->dst buffer overflow 2023-12-29 11:25:56 +08:00
Documentation bpf, docs: Clarify that MOVSX is only for BPF_X not BPF_K 2024-01-23 15:10:08 -08:00
drivers Including fixes from bpf and netfilter. 2024-01-18 17:33:50 -08:00
fs More eventfs fixes and a seq_buf fix for 6.8: 2024-01-18 14:45:33 -08:00
include bpf: Define struct bpf_tcp_req_attrs when CONFIG_SYN_COOKIES=n. 2024-01-23 15:08:03 -08:00
init Driver core changes for 6.8-rc1 2024-01-18 09:48:40 -08:00
io_uring Generic: 2024-01-17 13:03:37 -08:00
ipc shm: Slim down dependencies 2023-12-20 19:26:31 -05:00
kernel bpf: Refactor ptr alu checking rules to allow alu explicitly 2024-01-23 15:01:39 -08:00
lib cxl for v6.8 2024-01-18 16:22:43 -08:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm memblock: code readability improvement 2024-01-18 16:46:18 -08:00
net bpf: tcp: Support arbitrary SYN Cookie. 2024-01-23 14:40:24 -08:00
rust Rust changes for v6.8 2024-01-11 13:05:41 -08:00
samples tracing updates for 6.8: 2024-01-18 14:35:29 -08:00
scripts Char/Misc and other Driver changes for 6.8-rc1 2024-01-17 16:47:17 -08:00
security misc cleanups (the part that hadn't been picked by individual fs trees) 2024-01-11 20:23:50 -08:00
sound This cycle, I2C removes the currently unused CLASS_DDC support 2024-01-18 17:29:01 -08:00
tools libbpf: call dup2() syscall directly 2024-01-23 15:13:47 -08:00
usr usr/Kconfig: fix typos of "its" 2023-12-20 15:02:58 -08:00
virt Generic: 2024-01-17 13:03:37 -08:00
.clang-format clang-format: Update with v6.7-rc4's for_each macro list 2023-12-08 23:54:38 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: rpm-pkg: generate kernel.spec in rpmbuild/SPECS/ 2023-10-03 20:49:09 +09:00
.mailmap Char/Misc and other Driver changes for 6.8-rc1 2024-01-17 16:47:17 -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 Including fixes from bpf and netfilter. 2024-01-18 17:33:50 -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 Including fixes from bpf and netfilter. 2024-01-18 17:33:50 -08:00
Makefile Quite a lot of kexec work this time around. Many singleton patches in 2024-01-09 11:46:20 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.