kernel/linux.git/Documentation/admin-guide/sysctl/kernel.rst, branch v6.6.131

Merge tag 'io_uring-6.6-2023-09-08' of git://git.kernel.dk/linux

2023-09-09T04:32:28+00:00

Pull io_uring fixes from Jens Axboe: "A few fixes that should go into the 6.6-rc merge window: - Fix for a regression this merge window caused by the SQPOLL affinity patch, where we can race with SQPOLL thread shutdown and cause an oops when trying to set affinity (Gabriel) - Fix for a regression this merge window where fdinfo reading with for a ring setup with IORING_SETUP_NO_SQARRAY will attempt to deference the non-existing SQ ring array (me) - Add the patch that allows more finegrained control over who can use io_uring (Matteo) - Locking fix for a regression added this merge window for IOPOLL overflow (Pavel) - IOPOLL fix for stable, breaking our loop if helper threads are exiting (Pavel) Also had a fix for unreaped iopoll requests from io-wq from Ming, but we found an issue with that and hence it got reverted. Will get this sorted for a future rc" * tag 'io_uring-6.6-2023-09-08' of git://git.kernel.dk/linux: Revert "io_uring: fix IO hang in io_wq_put_and_exit from do_exit()" io_uring: fix unprotected iopoll overflow io_uring: break out of iowq iopoll on teardown io_uring: add a sysctl to disable io_uring system-wide io_uring/fdinfo: only print ->sq_array[] if it's there io_uring: fix IO hang in io_wq_put_and_exit from do_exit() io_uring: Don't set affinity on a dying sqpoll thread

io_uring: add a sysctl to disable io_uring system-wide

2023-09-05T14:34:07+00:00

Introduce a new sysctl (io_uring_disabled) which can be either 0, 1, or 2. When 0 (the default), all processes are allowed to create io_uring instances, which is the current behavior. When 1, io_uring creation is disabled (io_uring_setup() will fail with -EPERM) for unprivileged processes not in the kernel.io_uring_group group. When 2, calls to io_uring_setup() fail with -EPERM regardless of privilege. Signed-off-by: Matteo Rizzo [JEM: modified to add io_uring_group] Signed-off-by: Jeff Moyer Link: https://lore.kernel.org/r/x49y1i42j1z.fsf@segfault.boston.devel.redhat.com Signed-off-by: Jens Axboe

Documentation: admin-guide: Add riscv sysctl_perf_user_access

2023-08-16T14:28:21+00:00

riscv now uses this sysctl so document its usage for this architecture. Signed-off-by: Alexandre Ghiti

docs: arm64: Move arm64 documentation under Documentation/arch/

2023-06-21T14:51:51+00:00

Architecture-specific documentation is being moved into Documentation/arch/ as a way of cleaning up the top-level documentation directory and making the docs hierarchy more closely match the source hierarchy. Move Documentation/arm64 into arch/ (along with the Chinese equvalent translations) and fix up documentation references. Cc: Will Deacon Cc: Alex Shi Cc: Hu Haowen Cc: Paolo Bonzini Acked-by: Catalin Marinas Reviewed-by: Yantengsi Signed-off-by: Jonathan Corbet

docs: move x86 documentation into Documentation/arch/

2023-03-30T18:58:51+00:00

Move the x86 documentation under Documentation/arch/ as a way of cleaning up the top-level directory and making the structure of our docs more closely match the structure of the source directories it describes. All in-kernel references to the old paths have been updated. Acked-by: Dave Hansen Cc: linux-arch@vger.kernel.org Cc: x86@kernel.org Cc: Borislav Petkov Cc: Thomas Gleixner Link: https://lore.kernel.org/lkml/20230315211523.108836-1-corbet@lwn.net/ Signed-off-by: Jonathan Corbet

kexec: introduce sysctl parameters kexec_load_limit_*

2023-02-03T06:50:05+00:00

kexec allows replacing the current kernel with a different one. This is usually a source of concerns for sysadmins that want to harden a system. Linux already provides a way to disable loading new kexec kernel via kexec_load_disabled, but that control is very coard, it is all or nothing and does not make distinction between a panic kexec and a normal kexec. This patch introduces new sysctl parameters, with finer tuning to specify how many times a kexec kernel can be loaded. The sysadmin can set different limits for kexec panic and kexec reboot kernels. The value can be modified at runtime via sysctl, but only with a stricter value. With these new parameters on place, a system with loadpin and verity enabled, using the following kernel parameters: sysctl.kexec_load_limit_reboot=0 sysct.kexec_load_limit_panic=1 can have a good warranty that if initrd tries to load a panic kernel, a malitious user will have small chances to replace that kernel with a different one, even if they can trigger timeouts on the disk where the panic kernel lives. Link: https://lkml.kernel.org/r/20221114-disable-kexec-reset-v6-3-6a8531a09b9a@chromium.org Signed-off-by: Ricardo Ribalda Reviewed-by: Steven Rostedt (Google) Acked-by: Baoquan He Cc: Bagas Sanjaya Cc: "Eric W. Biederman" Cc: Guilherme G. Piccoli # Steam Deck Cc: Joel Fernandes (Google) Cc: Jonathan Corbet Cc: Philipp Rudo Cc: Ross Zwisler Cc: Sergey Senozhatsky Signed-off-by: Andrew Morton

Documentation: sysctl: correct kexec_load_disabled

2023-02-03T06:50:04+00:00

Patch series "kexec: Add new parameter to limit the access to kexec", v6. Add two parameter to specify how many times a kexec kernel can be loaded. These parameter allow hardening the system. While we are at it, fix a documentation issue and refactor some code. This patch (of 3): kexec_load_disabled affects both ``kexec_load`` and ``kexec_file_load`` syscalls. Make it explicit. Link: https://lkml.kernel.org/r/20221114-disable-kexec-reset-v6-0-6a8531a09b9a@chromium.org Link: https://lkml.kernel.org/r/20221114-disable-kexec-reset-v6-1-6a8531a09b9a@chromium.org Signed-off-by: Ricardo Ribalda Reviewed-by: Steven Rostedt (Google) Acked-by: Baoquan He Cc: Bagas Sanjaya Cc: "Eric W. Biederman" Cc: Guilherme G. Piccoli Cc: Joel Fernandes (Google) Cc: Jonathan Corbet Cc: Philipp Rudo Cc: Ross Zwisler Cc: Sergey Senozhatsky Signed-off-by: Andrew Morton

Merge tag 'loongarch-6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson

2022-12-19T14:23:27+00:00

Pull LoongArch updates from Huacai Chen: - Switch to relative exception tables - Add unaligned access support - Add alternative runtime patching mechanism - Add FDT booting support from efi system table - Add suspend/hibernation (ACPI S3/S4) support - Add basic STACKPROTECTOR support - Add ftrace (function tracer) support - Update the default config file * tag 'loongarch-6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson: (24 commits) LoongArch: Update Loongson-3 default config file LoongArch: modules/ftrace: Initialize PLT at load time LoongArch/ftrace: Add HAVE_FUNCTION_GRAPH_RET_ADDR_PTR support LoongArch/ftrace: Add HAVE_DYNAMIC_FTRACE_WITH_ARGS support LoongArch/ftrace: Add HAVE_DYNAMIC_FTRACE_WITH_REGS support LoongArch/ftrace: Add dynamic function graph tracer support LoongArch/ftrace: Add dynamic function tracer support LoongArch/ftrace: Add recordmcount support LoongArch/ftrace: Add basic support LoongArch: module: Use got/plt section indices for relocations LoongArch: Add basic STACKPROTECTOR support LoongArch: Add hibernation (ACPI S4) support LoongArch: Add suspend (ACPI S3) support LoongArch: Add processing ISA Node in DeviceTree LoongArch: Add FDT booting support from efi system table LoongArch: Use alternative to optimize libraries LoongArch: Add alternative runtime patching mechanism LoongArch: Add unaligned access support LoongArch: BPF: Add BPF exception tables LoongArch: Remove the .fixup section usage ...

Merge tag 'hardening-v6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

2022-12-14T20:20:00+00:00

Pull kernel hardening updates from Kees Cook: - Convert flexible array members, fix -Wstringop-overflow warnings, and fix KCFI function type mismatches that went ignored by maintainers (Gustavo A. R. Silva, Nathan Chancellor, Kees Cook) - Remove the remaining side-effect users of ksize() by converting dma-buf, btrfs, and coredump to using kmalloc_size_roundup(), add more __alloc_size attributes, and introduce full testing of all allocator functions. Finally remove the ksize() side-effect so that each allocation-aware checker can finally behave without exceptions - Introduce oops_limit (default 10,000) and warn_limit (default off) to provide greater granularity of control for panic_on_oops and panic_on_warn (Jann Horn, Kees Cook) - Introduce overflows_type() and castable_to_type() helpers for cleaner overflow checking - Improve code generation for strscpy() and update str*() kern-doc - Convert strscpy and sigphash tests to KUnit, and expand memcpy tests - Always use a non-NULL argument for prepare_kernel_cred() - Disable structleak plugin in FORTIFY KUnit test (Anders Roxell) - Adjust orphan linker section checking to respect CONFIG_WERROR (Xin Li) - Make sure siginfo is cleared for forced SIGKILL (haifeng.xu) - Fix um vs FORTIFY warnings for always-NULL arguments * tag 'hardening-v6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (31 commits) ksmbd: replace one-element arrays with flexible-array members hpet: Replace one-element array with flexible-array member um: virt-pci: Avoid GCC non-NULL warning signal: Initialize the info in ksignal lib: fortify_kunit: build without structleak plugin panic: Expose "warn_count" to sysfs panic: Introduce warn_limit panic: Consolidate open-coded panic_on_warn checks exit: Allow oops_limit to be disabled exit: Expose "oops_count" to sysfs exit: Put an upper limit on how often we can oops panic: Separate sysctl logic from CONFIG_SMP mm/pgtable: Fix multiple -Wstringop-overflow warnings mm: Make ksize() a reporting-only function kunit/fortify: Validate __alloc_size attribute results drm/sti: Fix return type of sti_{dvo,hda,hdmi}_connector_mode_valid() drm/fsl-dcu: Fix return type of fsl_dcu_drm_connector_mode_valid() driver core: Add __alloc_size hint to devm allocators overflow: Introduce overflows_type() and castable_to_type() coredump: Proactively round up to kmalloc bucket size ...

LoongArch: Add unaligned access support

2022-12-14T00:36:11+00:00

Loongson-2 series (Loongson-2K500, Loongson-2K1000) don't support unaligned access in hardware, while Loongson-3 series (Loongson-3A5000, Loongson-3C5000) are configurable whether support unaligned access in hardware. This patch add unaligned access emulation for those LoongArch processors without hardware support. Signed-off-by: Huacai Chen