Create two documents explaining various aspects around regression handling and tracking; one is aimed at users, the other targets developers. The texts among others describes the first rule of Linux kernel development and what it means in practice. They also explain what a regression actually is and how to report one properly. Both texts additionally provide a brief introduction to the bot the kernel's regression tracker uses to facilitate the work, but mention the use is optional. To sum things up, provide a few quotes from Linus in the document for developers to show how serious we take regressions. Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info> Link: https://lore.kernel.org/r/34e56d3588f22d7e0b4d635ef9c9c3b33ca4ac04.1644994117.git.linux@leemhuis.info Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Document the FAN_FS_ERROR event for user administrators and user space developers. Link: https://lore.kernel.org/r/20211025192746.66445-32-krisman@collabora.com Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jan Kara <jack@suse.cz>
Remove the WIP and two FIXME notes in the text to make it official, as it's now considered fully ready for consumption. To make sure this step is okay for people the intent of this change and the latest version of the text were posted to ksummit-discuss; nobody complained, thus lets move ahead. Add a footer to point out people can contact Thorsten directly in case they find something to improve in the text. Dear reporting-bugs.rst, I'm sorry to tell you, but that makes you fully obsolete and we thus have to let you go now. Thank you very much for your service, you in one form or another have been around for a long time. I'm sure over the years you got read a lot and helped quite a few people. But it's time to retire now. Rest in peace. Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> CC: Harry Wei <harryxiyou@gmail.com> CC: Alex Shi <alex.shi@linux.alibaba.com> CC: Federico Vaga <federico.vaga@vaga.pv.it> CC: Greg KH <gregkh@linuxfoundation.org> Link: https://lore.kernel.org/r/49c674c2d304d87e6259063580fda05267e8c348.1617113469.git.linux@leemhuis.info Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Pull networking updates from Jakub Kicinski:
"Core:
- support "prefer busy polling" NAPI operation mode, where we defer
softirq for some time expecting applications to periodically busy
poll
- AF_XDP: improve efficiency by more batching and hindering the
adjacency cache prefetcher
- af_packet: make packet_fanout.arr size configurable up to 64K
- tcp: optimize TCP zero copy receive in presence of partial or
unaligned reads making zero copy a performance win for much smaller
messages
- XDP: add bulk APIs for returning / freeing frames
- sched: support fragmenting IP packets as they come out of conntrack
- net: allow virtual netdevs to forward UDP L4 and fraglist GSO skbs
BPF:
- BPF switch from crude rlimit-based to memcg-based memory accounting
- BPF type format information for kernel modules and related tracing
enhancements
- BPF implement task local storage for BPF LSM
- allow the FENTRY/FEXIT/RAW_TP tracing programs to use
bpf_sk_storage
Protocols:
- mptcp: improve multiple xmit streams support, memory accounting and
many smaller improvements
- TLS: support CHACHA20-POLY1305 cipher
- seg6: add support for SRv6 End.DT4/DT6 behavior
- sctp: Implement RFC 6951: UDP Encapsulation of SCTP
- ppp_generic: add ability to bridge channels directly
- bridge: Connectivity Fault Management (CFM) support as is defined
in IEEE 802.1Q section 12.14.
Drivers:
- mlx5: make use of the new auxiliary bus to organize the driver
internals
- mlx5: more accurate port TX timestamping support
- mlxsw:
- improve the efficiency of offloaded next hop updates by using
the new nexthop object API
- support blackhole nexthops
- support IEEE 802.1ad (Q-in-Q) bridging
- rtw88: major bluetooth co-existance improvements
- iwlwifi: support new 6 GHz frequency band
- ath11k: Fast Initial Link Setup (FILS)
- mt7915: dual band concurrent (DBDC) support
- net: ipa: add basic support for IPA v4.5
Refactor:
- a few pieces of in_interrupt() cleanup work from Sebastian Andrzej
Siewior
- phy: add support for shared interrupts; get rid of multiple driver
APIs and have the drivers write a full IRQ handler, slight growth
of driver code should be compensated by the simpler API which also
allows shared IRQs
- add common code for handling netdev per-cpu counters
- move TX packet re-allocation from Ethernet switch tag drivers to a
central place
- improve efficiency and rename nla_strlcpy
- number of W=1 warning cleanups as we now catch those in a patchwork
build bot
Old code removal:
- wan: delete the DLCI / SDLA drivers
- wimax: move to staging
- wifi: remove old WDS wifi bridging support"
* tag 'net-next-5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1922 commits)
net: hns3: fix expression that is currently always true
net: fix proc_fs init handling in af_packet and tls
nfc: pn533: convert comma to semicolon
af_vsock: Assign the vsock transport considering the vsock address flags
af_vsock: Set VMADDR_FLAG_TO_HOST flag on the receive path
vsock_addr: Check for supported flag values
vm_sockets: Add VMADDR_FLAG_TO_HOST vsock flag
vm_sockets: Add flags field in the vsock address data structure
net: Disable NETIF_F_HW_TLS_TX when HW_CSUM is disabled
tcp: Add logic to check for SYN w/ data in tcp_simple_retransmit
net: mscc: ocelot: install MAC addresses in .ndo_set_rx_mode from process context
nfc: s3fwrn5: Release the nfc firmware
net: vxget: clean up sparse warnings
mlxsw: spectrum_router: Use eXtended mezzanine to offload IPv4 router
mlxsw: spectrum: Set KVH XLT cache mode for Spectrum2/3
mlxsw: spectrum_router_xm: Introduce basic XM cache flushing
mlxsw: reg: Add Router LPM Cache Enable Register
mlxsw: reg: Add Router LPM Cache ML Delete Register
mlxsw: spectrum_router_xm: Implement L-value tracking for M-index
mlxsw: reg: Add XM Router M Table Register
...
Pull core entry/exit updates from Thomas Gleixner:
"A set of updates for entry/exit handling:
- More generalization of entry/exit functionality
- The consolidation work to reclaim TIF flags on x86 and also for
non-x86 specific TIF flags which are solely relevant for syscall
related work and have been moved into their own storage space. The
x86 specific part had to be merged in to avoid a major conflict.
- The TIF_NOTIFY_SIGNAL work which replaces the inefficient signal
delivery mode of task work and results in an impressive performance
improvement for io_uring. The non-x86 consolidation of this is
going to come seperate via Jens.
- The selective syscall redirection facility which provides a clean
and efficient way to support the non-Linux syscalls of WINE by
catching them at syscall entry and redirecting them to the user
space emulation. This can be utilized for other purposes as well
and has been designed carefully to avoid overhead for the regular
fastpath. This includes the core changes and the x86 support code.
- Simplification of the context tracking entry/exit handling for the
users of the generic entry code which guarantee the proper ordering
and protection.
- Preparatory changes to make the generic entry code accomodate S390
specific requirements which are mostly related to their syscall
restart mechanism"
* tag 'core-entry-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (36 commits)
entry: Add syscall_exit_to_user_mode_work()
entry: Add exit_to_user_mode() wrapper
entry_Add_enter_from_user_mode_wrapper
entry: Rename exit_to_user_mode()
entry: Rename enter_from_user_mode()
docs: Document Syscall User Dispatch
selftests: Add benchmark for syscall user dispatch
selftests: Add kselftest for syscall user dispatch
entry: Support Syscall User Dispatch on common syscall entry
kernel: Implement selective syscall userspace redirection
signal: Expose SYS_USER_DISPATCH si_code type
x86: vdso: Expose sigreturn address on vdso to the kernel
MAINTAINERS: Add entry for common entry code
entry: Fix boot for !CONFIG_GENERIC_ENTRY
x86: Support HAVE_CONTEXT_TRACKING_OFFSTACK
context_tracking: Only define schedule_user() on !HAVE_CONTEXT_TRACKING_OFFSTACK archs
sched: Detect call to schedule from critical entry code
context_tracking: Don't implement exception_enter/exit() on CONFIG_HAVE_CONTEXT_TRACKING_OFFSTACK
context_tracking: Introduce HAVE_CONTEXT_TRACKING_OFFSTACK
x86: Reclaim unused x86 TI flags
...
Make various places which point to Documentation/admin-guide/reporting-bugs.rst point to Documentation/admin-guide/reporting-issues.rst instead. That document is brand new and as of now is not completely finished. But even at this stage it's a lot more helpful and accurate than reporting-bugs.rst. Hence also add a note to reporting-bugs.rst, telling people they're better off reading reporting-issues.rst instead. reporting-bugs.rst is scheduled for removal once reporting-issues.rst is considered ready. Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info> Link: https://lore.kernel.org/r/3df7c2d16de112b47bb6e6158138608e78562bf5.1607063223.git.linux@leemhuis.info Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Add a mostly finished document describing how to report issues with the Linux kernel to its developers. It is designed to be a lot more straight forward and easier to follow than the current text about this (Documentation/admin-guide/reporting-bugs.rst); at the same time the new text should be more helpful for people unfamiliar with the topic, as it provides a lot more details, too. The main work on the text is done, but some polishing is still needed. The text also needs to be reviewed by more people and a few issues still might need some discussion. To make these tasks easier, it was decided ([1]) to add this document to the kernel sources in parallel to the existing text; the latter will be removed once this text is considered good enough(tm). This document is quite long and provides a lot of details, but was carefully crafted to make sure it's can also serve people that are in a hurry. That's mainly achieved by having a TDLR and a step-by-step guide, which should be good enough for quite a lot of people. Everybody that wants or need more explanations can find them in a reference section, which describes all the needed steps in detail. Thanks to this structure the text can work for kernel developers that just need to look something up, experienced FLOSS contributors that are unfamiliar with the kernel's bug reporting workflow, and users reporting something upstream for the first time. The text is thus a bit like the kernel itself, which works well for embedded machines, a typical desktop PC, cloud servers, and HPC. The document was written in the hope it will improve the quality of the bug reports, especially those that come from people unfamiliar with how Linux kernel development works. Sadly quite a few reports from this group are currently of poor quality and/or get submitted to the wrong place. Part of the problem is the old reporting-bugs document, as it makes its essence hard to grasp; it's and also inaccurate and slightly outdated in a few spots. Due to this quite a few valid reports are ignored in the end, which is annoying for those that compiled them and bad for the kernel's quality. The document near the top points out that it's still unfinished, but nevertheless ready for consumption. Those few areas in the text that might need some further discussion contain a note pointing this out. Besides lack of review from core developers there is only one major issue left: the section 'Decode failure message' is known to be outdated: it's waiting for someone familiar with the topic to write something up or give at least provide some hints and pointers what to write there. The new document is dual-licensed under GPL-2.0+ or CC-BY-4.0. The latter is way more liberal and makes it attractive to use this text as a base when writing about this topic on websites or in books. This hopefully increases the chances that such texts are accurate and stick to official way of doing things. [1] https://lkml.kernel.org/r/20201118172958.5b014a44@lwn.net Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info> CC: Thomas Gleixner <tglx@linutronix.de> CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org> CC: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/e2db808f954744b79f10937a923d9c99bdca1fca.1607063223.git.linux@leemhuis.info Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Add a feature list matrix at the admin-guide. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/f6c1e366fbc7ce1c9c94c7dc6c7852c6377cc0be.1606748711.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Explain the interface, provide some background and security notes. [ tglx: Add note about non-visibility, add it to the index and fix the kerneldoc warning ] Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Andy Lutomirski <luto@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20201127193238.821364-8-krisman@collabora.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>