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Thomas Gleixner abc850e761 rseq: Provide and use rseq_update_user_cs()
Provide a straight forward implementation to check for and eventually
clear/fixup critical sections in user space.

The non-debug version does only the minimal sanity checks and aims for
efficiency.

There are two attack vectors, which are checked for:

  1) An abort IP which is in the kernel address space. That would cause at
     least x86 to return to kernel space via IRET.

  2) A rogue critical section descriptor with an abort IP pointing to some
     arbitrary address, which is not preceded by the RSEQ signature.

If the section descriptors are invalid then the resulting misbehaviour of
the user space application is not the kernels problem.

The kernel provides a run-time switchable debug slow path, which implements
the full zoo of checks including termination of the task when one of the
gazillion conditions is not met.

Replace the zoo in rseq.c with it and invoke it from the TIF_NOTIFY_RESUME
handler. Move the remainders into the CONFIG_DEBUG_RSEQ section, which will
be replaced and removed in a subsequent step.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20251027084307.151465632@linutronix.de
2025-11-04 08:32:57 +01:00
arch entry: Remove syscall_enter_from_user_mode_prepare() 2025-11-04 08:31:37 +01:00
block block-6.18-20251031 2025-10-31 12:57:19 -07:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto This push contains the following changes: 2025-10-10 08:56:16 -07:00
Documentation rseq: Provide static branch for runtime debugging 2025-11-04 08:32:49 +01:00
drivers rseq, virt: Retrigger RSEQ after vcpu_run() 2025-11-04 08:30:23 +01:00
fs rseq: Simplify the event notification 2025-11-04 08:30:09 +01:00
include rseq: Provide and use rseq_update_user_cs() 2025-11-04 08:32:57 +01:00
init rseq: Provide static branch for runtime debugging 2025-11-04 08:32:49 +01:00
io_uring io_uring: fix buffer auto-commit for multishot uring_cmd 2025-10-23 19:41:31 -06:00
ipc namespace-6.18-rc1 2025-09-29 11:20:29 -07:00
kernel rseq: Provide and use rseq_update_user_cs() 2025-11-04 08:32:57 +01:00
lib Second round of Kbuild fixes for 6.19 2025-11-01 10:00:53 -07:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
mm slab fixes for 6.18-rc3 2025-10-24 12:40:51 -07:00
net bpf-fixes 2025-10-31 18:22:26 -07:00
rust Driver core fixes for 6.18-rc3 2025-10-25 11:03:46 -07:00
samples Char/Misc/IIO/Binder changes for 6.18-rc1 2025-10-04 16:26:32 -07:00
scripts kconfig/nconf: Initialize the default locale at startup 2025-11-01 00:23:22 -04:00
security integrity-v6.18 2025-10-05 10:48:33 -07:00
sound ASoC: Fixes for v6.18 2025-10-30 13:08:08 +01:00
tools objtool: Fix skip_alt_group() for non-alternative STAC/CLAC 2025-11-01 07:43:20 +01:00
usr gen_init_cpio: Ignore fsync() returning EINVAL on pipes 2025-10-07 09:53:05 -07:00
virt rseq, virt: Retrigger RSEQ after vcpu_run() 2025-11-04 08:30:23 +01:00
.clang-format memblock: drop for_each_free_mem_pfn_range_in_zone_from() 2025-09-14 08:49:03 +03:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: remove Alyssa Rosenzweig 2025-09-18 21:17:31 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore .gitignore: ignore compile_commands.json globally 2025-08-12 15:53:55 -07:00
.mailmap linux_kselftest-kunit-fixes-6.18-rc4 2025-10-30 19:11:27 -07:00
.pylintrc tools: docs: parse-headers.py: move it from sphinx dir 2025-08-29 15:54:42 -06:00
.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 MAINTAINERS: mark ISDN subsystem as orphan 2025-10-27 17:49:45 -07:00
Kbuild sched: Make migrate_{en,dis}able() inline 2025-09-25 09:57:16 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS Second round of Kbuild fixes for 6.19 2025-11-01 10:00:53 -07:00
Makefile Linux 6.18-rc4 2025-11-02 11:28:02 -08:00
README README: Fix spelling 2024-03-18 03:36:32 -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 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.