linux/Documentation/admin-guide/sysctl/kernel.rst, branch v5.12

docs: Update documentation to reflect what TAINT_CPU_OUT_OF_SPEC means

2020-12-08T17:53:58Z

Here's a patch updating the meaning of TAINT_CPU_OUT_OF_SPEC after Borislav introduced changes in a7e1f67ed29f and upcoming patches in tip. TAINT_CPU_OUT_OF_SPEC now means a bit more what it implies as the flag isn't set just because of a CPU misconfiguration or mismatch. Historically it was for SMP kernel oops on an officially SMP incapable processor but now it also covers CPUs whose MSRs have been incorrectly poked at from userspace, drivers being used on non supported architectures, broken firmware, mismatched CPUs, ... Update documentation and script to reflect that. Signed-off-by: Mathieu Chouquet-Stringer Link: https://lore.kernel.org/r/20201202153244.709752-1-me@mathieu.digital Signed-off-by: Jonathan Corbet

Documentation: fix multiple typos found in the admin-guide subdirectory

2020-12-08T17:27:56Z

Fix thirty five typos in dm-integrity.rst, dm-raid.rst, dm-zoned.rst, verity.rst, writecache.rst, tsx_async_abort.rst, md.rst, bttv.rst, dvb_references.rst, frontend-cardlist.rst, gspca-cardlist.rst, ipu3.rst, remote-controller.rst, mm/index.rst, numaperf.rst, userfaultfd.rst, module-signing.rst, imx-ddr.rst, intel-speed-select.rst, intel_pstate.rst, ramoops.rst, abi.rst, kernel.rst, vm.rst Signed-off-by: Andrew Klychkov Link: https://lore.kernel.org/r/20201204072848.GA49895@spblnx124.lan Signed-off-by: Jonathan Corbet

docs: clean up sysctl/kernel: titles, version

2020-12-08T17:22:21Z

This cleans up a few titles with extra colons, and removes the reference to kernel 2.2. The docs don't yet cover *all* of 5.10 or 5.11, but I think they're close enough. Most entries are documented, and have been checked against current kernels. Signed-off-by: Stephen Kitt Link: https://lore.kernel.org/r/20201208074922.30359-1-steve@sk2.org Signed-off-by: Jonathan Corbet

coredump: add %f for executable filename

2020-08-12T17:58:01Z

The document reads "%e" should be "executable filename" while actually it could be changed by things like pr_ctl PR_SET_NAME. People who uses "%e" in core_pattern get surprised when they find out they get thread name instead of executable filename. This is either a bug of document or a bug of code. Since the behavior of "%e" is there for long time, it could bring another surprise for users if we "fix" the code. So we just "fix" the document. And more, for users who really need the "executable filename" in core_pattern, we introduce a new "%f" for the real executable filename. We already have "%E" for executable path in kernel, so just reuse most of its code for the new added "%f" format. Signed-off-by: Lepton Wu Signed-off-by: Andrew Morton Link: http://lkml.kernel.org/r/20200701031432.2978761-1-ytht.net@gmail.com Signed-off-by: Linus Torvalds

Merge tag 'docs-5.9' of git://git.lwn.net/linux

2020-08-05T05:47:54Z

Pull documentation updates from Jonathan Corbet: "It's been a busy cycle for documentation - hopefully the busiest for a while to come. Changes include: - Some new Chinese translations - Progress on the battle against double words words and non-HTTPS URLs - Some block-mq documentation - More RST conversions from Mauro. At this point, that task is essentially complete, so we shouldn't see this kind of churn again for a while. Unless we decide to switch to asciidoc or something...:) - Lots of typo fixes, warning fixes, and more" * tag 'docs-5.9' of git://git.lwn.net/linux: (195 commits) scripts/kernel-doc: optionally treat warnings as errors docs: ia64: correct typo mailmap: add entry for doc/zh_CN: add cpu-load Chinese version Documentation/admin-guide: tainted-kernels: fix spelling mistake MAINTAINERS: adjust kprobes.rst entry to new location devices.txt: document rfkill allocation PCI: correct flag name docs: filesystems: vfs: correct flag name docs: filesystems: vfs: correct sync_mode flag names docs: path-lookup: markup fixes for emphasis docs: path-lookup: more markup fixes docs: path-lookup: fix HTML entity mojibake CREDITS: Replace HTTP links with HTTPS ones docs: process: Add an example for creating a fixes tag doc/zh_CN: add Chinese translation prefer section doc/zh_CN: add clearing-warn-once Chinese version doc/zh_CN: add admin-guide index doc:it_IT: process: coding-style.rst: Correct __maybe_unused compiler label futex: MAINTAINERS: Re-add selftests directory ...

Documentation/sysctl: Document uclamp sysctl knobs

2020-07-29T11:51:48Z

Uclamp exposes 3 sysctl knobs: * sched_util_clamp_min * sched_util_clamp_max * sched_util_clamp_min_rt_default Document them in sysctl/kernel.rst. Signed-off-by: Qais Yousef Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20200716110347.19553-3-qais.yousef@arm.com

Documentation/admin-guide: sysctl/kernel: drop doubled word

2020-07-05T20:01:49Z

Drop the doubled word "set". Signed-off-by: Randy Dunlap Cc: Jonathan Corbet Cc: linux-doc@vger.kernel.org Link: https://lore.kernel.org/r/20200704032020.21923-12-rdunlap@infradead.org Signed-off-by: Jonathan Corbet

docs: sysctl/kernel: document random

2020-06-26T17:25:14Z

This documents the random directory, based on the behaviour seen in drivers/char/random.c. Signed-off-by: Stephen Kitt Link: https://lore.kernel.org/r/20200623112514.10650-1-steve@sk2.org Signed-off-by: Jonathan Corbet

Documentation: fix sysctl/kernel.rst heading format warnings

2020-06-19T19:24:57Z

Fix heading format warnings in admin-guide/sysctl/kernel.rst: Documentation/admin-guide/sysctl/kernel.rst:339: WARNING: Title underline too short. hung_task_all_cpu_backtrace: ================ Documentation/admin-guide/sysctl/kernel.rst:650: WARNING: Title underline too short. oops_all_cpu_backtrace: ================ Fixes: 0ec9dc9bcba0 ("kernel/hung_task.c: introduce sysctl to print all traces when a hung task is detected") Fixes: 60c958d8df9c ("panic: add sysctl to dump all CPUs backtraces on oops event") Signed-off-by: Randy Dunlap Reviewed-by: Mauro Carvalho Chehab Link: https://lore.kernel.org/r/8af1cb77-4b5a-64b9-da5d-f6a95e537f99@infradead.org Signed-off-by: Jonathan Corbet

panic: add sysctl to dump all CPUs backtraces on oops event

2020-06-08T18:05:56Z

Usually when the kernel reaches an oops condition, it's a point of no return; in case not enough debug information is available in the kernel splat, one of the last resorts would be to collect a kernel crash dump and analyze it. The problem with this approach is that in order to collect the dump, a panic is required (to kexec-load the crash kernel). When in an environment of multiple virtual machines, users may prefer to try living with the oops, at least until being able to properly shutdown their VMs / finish their important tasks. This patch implements a way to collect a bit more debug details when an oops event is reached, by printing all the CPUs backtraces through the usage of NMIs (on architectures that support that). The sysctl added (and documented) here was called "oops_all_cpu_backtrace", and when set will (as the name suggests) dump all CPUs backtraces. Far from ideal, this may be the last option though for users that for some reason cannot panic on oops. Most of times oopses are clear enough to indicate the kernel portion that must be investigated, but in virtual environments it's possible to observe hypervisor/KVM issues that could lead to oopses shown in other guests CPUs (like virtual APIC crashes). This patch hence aims to help debug such complex issues without resorting to kdump. Signed-off-by: Guilherme G. Piccoli Signed-off-by: Andrew Morton Reviewed-by: Kees Cook Cc: Luis Chamberlain Cc: Iurii Zaikin Cc: Thomas Gleixner Cc: Vlastimil Babka Cc: Randy Dunlap Cc: Matthew Wilcox Link: http://lkml.kernel.org/r/20200327224116.21030-1-gpiccoli@canonical.com Signed-off-by: Linus Torvalds